Nutrition And Diet
Understanding Nutrition And Your Diet
Nutrition and diet: From prenatal throughout life, people must have adequate nutrition to prevent malnourishment and minimize the development of illnesses that may be worsened by poor dietary practices.
Food supports growth and development by providing the body with the nutrients needed for the production of energy, repair of damaged tissue, growth of new tissue, and regulation of physiological processes, all of which undergird full participation in the activities that constitute our days, weeks, months, and years of living. But our diets are more than that.
Our food selection reflects personal, familial, and cultural traditions. The preparation and serving of food at regular mealtimes and during holiday gatherings and other special occasions enhances all of the dimensions of health.
For example, taking bread and wine during Communion supports the spiritual dimension of health, sharing popcorn at the movies with your friends enhances the social dimension of health, and learning about the cuisine of another culture develops the intellectual dimension of health.
As you read this chapter, keep in mind this balanced view of food as sustenance and food as a resource for the dimensions of health.
Real Life And Real Choices
Diet and Lifestyle: Finding a Healthy Balance
- Name: Vincent and Angela Martinelli
- Ages: 64 and 61
- Ethnic background: Italian
- Occupation: Restaurant owners
- Physical characteristics: Vincent: 5’9”, 189lb. Angela: 5’2”, 143 lb.
Does anyone really know how many kinds of pasta there are in the world? If you want an expert opinion, the people to ask are Vincent and Angela Martinelli. The owners of a popular market and deli in their city’s lively Italian neighborhood.
Martinelli’s Fine Foods was started by Vincent’s father in the 1920s, and Vincent began helping out when he was five years old. When his father died in the early 1950s, Vincent and Angela took over.
Now in their sixties, they’re beginning to talk about retiring and turning the business over to their daughter and her husband.
A family business like Martinelli’s isn’t a nine-to-five proposition, for more than forty years, Vincent and Angela have routinely worked twelve to fourteen hours a day, six days a week- at the same time raising five children and putting them through college.
Their hectic, stressful schedule has left them little time for leisure, and they’re looking forward to making life easier when they retire.
Both Vincent and Angela enjoy cooking-and eating the delicious they offer for sale in the deli and for catered parties. Their favorite is fettuccine carbonara, which features pasta in cream sauce with bacon.
At a recent checkup, the Martinellis physician found that Vincent’s serum cholesterol level is elevated to the point where heart disease is a concern; and Angela, who has a family history of hypertension, is taking in as much as 3.000 milligrams of sodium per day.
As you study this chapter, think about some steps Vincent and Angela can take to adopt a healthier lifestyle, and prepare yourself to answer the questions in Your Turn at the end of the chapter.
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Types and Sources of Nutrients
Your body relies on seven nutrients to carry out its physiological functions: carbohydrates, fats, protein, vitamins, minerals, dietary fiber, and water.* The first three- carbohydrates, fats, and protein will be discussed together because they provide Calories +.
These calories are either used quickly by our bodies in energy metabolism or are stored in the form of glycogen or adipose tissue for delayed use as energy sources.
The other nutrients-vitamins, minerals, dietary fiber, and water-are not sources of calories for the body. Their functions will be discussed later in the chapter.
Carbohydrates are various combinations of sugar units or saccharides. The body uses carbohydrates primarily for energy. Each gram of carbohydrate contains four calories.
Since the average person requires approximately 2,000 calories per day and about 60 percent of our calories come from carbohydrates, we obtain 1,200 calories per day from carbohydrates1.
Carbohydrates occur in three forms, depending on the number of saccharides (sugar) units that make up the molecule.
Carbohydrates that contain only one saccharide unit are classified as monosaccharides, those with two units are disaccharides, and those with more than two are polysaccharides.
Monosaccharides and disaccharides are more commonly called sugar, whereas polysaccharides are referred to as starches.
Today it is recommended that about 58 percent to 60 percent of our total calorie intake come from carbohydrates, with approximately 50 percent from starches and only 10 percent from sugars.
- *Since most of our water intake comes from beverages rather than from food, some nutritionists do not consider water a nutrient, even though it is essential for life.
- +The tern calorie is used here to refer to kilocalorie (1,000 calories), which is the accepted scientific expression of the energy value of a food.
The shared preparation and serving of nourishing meals enhance your overall well-being.
Monosaccharides are the simplest sugar units. Four forms of monosaccharides exist glucose, fructose, galactose, and an infrequently found form, mannose. Of these, glucose is the most important monosaccharide; it makes up the blood sugar used as the body’s primary source of energy.
It is almost the sole source of energy for the brain and nervous system. Glucose, also known as dextrose, is found in vegetables, honey, molasses, fruits, and syrup.
Fructose, also called levulose, is another monosaccharide that provides a source of simple sugar. This simple sugar is most often derived from fruits and berries.
Disaccharides are sugars composed of two monosaccharides, one of which is always a glucose unit. Sucrose is perhaps the most widely recognized disaccharide source; it is better known as table sugar.
Sucrose is a combination of glucose and a fructose molecule. Other disaccharides include maltose, derived from germinating cereals, and lactose, the carbohydrate found in human and animal milk.
The average adult American now ingests approximately 125 pounds of source each year- usually in colas, candies, and pastries, which offer few additional nutritional benefits2.
For years excess sugar concerns, including obesity, micronutrient deficiencies, behavioral disorders, dental caries, diabetes mellitus, and cardiovascular disease.
With the exception of dental caries, current scientific data fail to confirm that sugar per se directly causes any of these health problems.
However, the inability of some people to digest milk sugar (lactose) is well documented. Lactose-intolerant people lack an enzyme used in the digestion of this simple sugar.
The brisk sales of enzyme supplements now available near dairy cases in supermarkets may suggest, however, that the problem is more widespread than experts believe.
Regardless, today it is recommended that no more than 10 percent of our total calories come from sucrose and other sweeteners.
Much of the sugar we consume is hidden; that is, sugar is a principal product we may overlook in a large number of food items.
Foods such as ketchup, salad dressings, cured meat products, and canned vegetables and fruits frequently contain much-hidden sugar. Corn syrup, frequently found in these items, is a very concentrated sucrose solution.
Polysaccharides are complex carbohydrates that are composed of long chains of glucose units. These long chains are better known as starches. they are among the most important sources of dietary carbohydrates.
Starches are found primarily in vegetables, fruits, and grains. Consumption of starches helps people receive many overall nutritional benefits since most starch sources also contain significant portions of vitamins, minerals, protein, and water.
Dietary fiber is also a polysaccharide. Starches are nutritional “good guys”.
Fats (lipids, fatty acids) are an important nutrient in our diets. Fats provide a concentrated form of energy (mine calories per gram consumed versus four for carbohydrates and protein) and help give our foods high satiety value.
Fats food help to give our food its pleasing taste, or palatability. Fats also serve as carriers of fat-soluble vitamins A, D, E, and K. Without fat, these vitamins would quickly pass through the body. Fat insulates the body and helps it retain heat.
Dietary sources of fat are often difficult to identify. The visible fats in our diet, such as butter, salad oils, and the layer of fat on some cuts of meat, represent only about 40 percent of the fat we consume.
Most of the fat we eat is “hidden” in food because it is incorporated into the food during preparation or used to fry the food, or it is in food that we have not learned to recognize as being high in fat, such as a candy bar.
When shopping, we often notice that the fat content of some foods is reported by its percentage of the product’s weight. In selecting the type of milk ranges from skim milk (0% fat) to ultra low-fat milk (0.5%) through low-fat milk (1% to 2%) to whole milk ( 3% to 4%).
(The lists the fat and calories in various kinds of milk). Most consumers do not know, however, how much of the product’s calories are derived from fat.
Today, it is recommended that no more than 25 percent to 30 percent of our calories come from fat. Complete the Personal Assessment to see whether you eat too many fatty foods. If so, the Health Action Guide offers tips for reducing the amount of fat in your diet.
It is important for parents of infants and toddlers to know that current medical opinion advises strongly against any limiting of fats in the diets of children younger than two of ages 3.
This recommendation is, of course, based on the demands for energy and the nutritional requirements that accompany the rapid growth that occurs during this formative stage of life.
Every type of dietary fat is made up of a combination of three forms of fat (saturated, monounsaturated, and polyunsaturated), based on chemical composition.
Today, consumers need to pay attention to the amount of each type of fat in dietary fat because of the role that each form plays in heart disease.
Saturated fats, including those found in animal sources and in vegetable oils to which hydrogen has been added (hydrogenated), becoming trans-fatty acids, need to be carefully limited on a modern healthy diet.
The presence of trans-fatty acids ( an altered form of normal vegetable oil molecule) is associated with changes in the cell membrane, including those cells lining the artery wall.
This possibly prevents these vessel wall cells from freeing cholesterol from their surfaces4. The amount of trans-fatty acids in the diet can be reduced by using liquefied margarine rather than the solid stick forms.
Fortunately, the replacement of saturated fats with monounsaturated and polyunsaturated fats and oils appears to lower blood cholesterol levels and reduce the risk of heart disease 5. Vegetable oils tend to be low in saturated fats, with the exception of the tropical oils (coconut, palm, and palm kernel oils).
Monounsaturated fats are found in high quantities in olive oil, peanut oil, and sesame oil. Polyunsaturated fats are especially prevalent in safflower oil, sunflower oil, and corn oil.
In recent years, interest has ebbed and flowed regarding the role of omega-3 fatty acid, a long-chain polyunsaturated fat (twenty carbon atoms) obtained by eating fatty fish, such as tuna, salmon, and sardines6.
As a member of the essential fatty acids, the body can convert omega-3 into a hormonelike substance that possesses the ability to slow the clotting of blood, thus minimizing clot formation- a particular risk for people with cardiovascular disease.
Unfortunately, when consumed excessively, omega-3 can predispose people to hemorrhagic stroke resulting from the inability of the blood to clot quickly enough6.
In light of this interesting potential to both help and hurt, no major health organization in this country, including the American Heart Association, has felt comfortable recommending supplemental omega03.6 Nevertheless, supplements are available in the form of over-the-counter (OTG) fish-oil capsules.
- Nutrients elements in foods that are required for the growth, repair, and regulation of body processes.
- Calories units of heat (energy); specifically, one calorie (used here to mean kilocalorie) equals the heat required to raise the temperature of one kilogram of water one degree Celsius.
- Carbohydrates chemical compounds comprising sugar (or saccharide) units; the body’s primary source of energy.
- Satiety (Suh tie uh tee) a feeling of no longer being hungry; a diminished desire to eat.
*Skimming Off Fat, Calories, and Cholesterol
Below is a comparison of calories, fat, and cholesterol in I cup of several types of milk:
- Whole. 150 calories, 8 grams of fat, 5 grams of saturated fat, 33 mg of cholesterol
- 2%. 120 calories, 5 grams of fat, 3 grams of saturated fat. 18 mg of cholesterol
- 1%. 100 calories, 2.5 grams of fat, 1.5 grams of saturated fat, 10 mg of cholesterol
- Skim. 80 calories, 0 fat, 0 saturated fat, 4 mg of cholesterol
Although all cooking oils (and fats such as butter, lard, margarine, and shortening) have the same number of calories by weight (nine calories per gram), some oils contain high percentages of saturated fats.
All oils and fats contain varying percentages of saturated, monounsaturated, and polyunsaturated fats.
Saturated fats are known to elevate blood cholesterol levels and increase the chances of developing heart disease. The tropical oils-coconut, palm, and palm kernel-contain much higher percentages of saturated fats than do other cooking oils.
Coconut oil is 92 percent saturated fat(see Figure 5-1). Tropical oils can still be found in some brands of snack foods, crackers, cookies, nondairy creamers, and breakfast cereals, although they have been removed from most national brands. Do you check for tropical oils on the ingredients labels of the foods you select?
Figure 5-1 Comparison of dietary fats. (Fatty acid content normalized to 100%.)
A high level of cholesterol has also been reported to be a risk factor in the development of cardiovascular disease. Cholesterol is a necessary constituent of all animal tissue and is synthesized by our own bodies from carbohydrates and fats.
Considerable evidence suggests that increased intake of saturated fats may increase serum (blood) cholesterol levels7.
- Saturated fats that are difficult for the body to use; these are fats in solid form at room temperature primarily animal fats.
- Cholesterol a primary form of fat found in the blood; li[id material manufactured within the body, as well as derived from dietary sources.
Do You Have Fatty Habits?
Fat has earned a bad reputation because of the health problems to which it contributes when we eat too much of it. The questionnaire below will help you think about the amounts and types of fat that you generally eat.
For each general type of food or food habits, circle the response category that is most typical for you. If you never or almost never eat any items of a particular food type, just skip that type.
|Food type/habit of high fat||High fat||Medium fat||Low fat|
|Chicken||fried with||baked, broiled, or barbecued with the skin||baked, broiled, or barbecued without the skin|
|Fat present on means||Usually, eat||Sometimes eat||Never eat|
|Fat used in cooking||Butter, lard, bacon grease, chicken fat||Margarine, oil||Nonstick cooking spray or no fat used|
|Additions to rice, bread, potatoes, vegetables, etc.||Butter, lard, bacon grease, chicken fat, coconut oil, cream cheese||Margarine, oil, peanut butter||Butter-flavored granules or no fat used|
|Pizza toppings||Sausage, pepperoni, extra cheese, combination||Canadian bacon||Vegetable|
|Sandwich spreads||Mayonnaise or mayonnaise-type dressing||Light mayonnaise, oil, and vinegar||Mustard, fat-free mayonnaise|
|Milk and milk products (e.g., yogurt)||Whole milk and whole-milk products||Low-fat milk and milk products||Skim milk and milk products|
|Sandwich side orders||Chips, potato salad, macaroni salad with creamy dressing||Coleslaw, pasta salad with a clear dressing||Vegetable sticks, pretzels, pickle|
|Salad dressings||Blue cheese, ranch, Thousand Island, another creamy type||oil and vinegar, clear-base dressing||Oil-free dressing, lemon juice, flavored vinegar|
|Typical meat protein is eaten||6-8 ounces or more||4-5 ounces||2-3 ounces|
|Sandwich fillings||beef or pork hot dogs, salami, bologna, pepperoni, cheese, tuna or chicken salad||Turkey hot dogs, 85% fat-free lunch meats, corned beef, peanut butter, hummus (chickpea paste)||95% fat-free lunch meats, roast turkey, roast beef, lean ham|
|Ground meats||Regular ground beef, sausage meat, ground meat, ground pork (about 30% fat)||Lean ground beef, ground chuck, turkey sausage meat (20%-25% fat)||Ground turkey, extra-lean ground beef, ground beef, ground round (about 15% fat)|
|Deep-fried foods (e.g., french fries, onion rings, fish or chicken patties, egg rolls, tempura)||Eat every day||Eat once a week||Eat once a month or never|
|Food Type/Habit||High Fat||Medium Fat||Low Fat|
|Bread for sandwiches||Croissant||Biscuit||Whole wheat, French, tortilla, pita or pocket bread, bagel, sourdough, or English muffin|
|Cheeses||Hard cheeses (e.g., cheddar, Swiss, provolone, jack, American, processed)||Part-skim mozzarella, part-skim ricotta, low-fat cheeses||Nonfat cheeses, nonfat cottage cheese, no cheese|
|Frozen desserts||Premium or regular ice cream||Ice milk or low-fat frozen yogurt||Sherbet, Italian water ice, nonfat frozen yogurt, frozen fruit whip|
|Coffee lighteners||Cream, liquid or powdered creamer||Whole milk||Low-fat or skim milk|
|Snacks||Chips, pies, cheese and crackers, nuts, donuts, microplate, granola bars||Muffins, toaster pastries, unbuttered commercial popcorn||Pretzels, vegetable sticks, fresh or dried fruit, air-popped popcorn, breadsticks, jelly beans, hard candy|
|Cookies||Chocolate coated, coated, chocolate chip, peanut butter, filled sandwich-type||Oatmeal||Ginger snaps, vanilla wafers, graham crackers, animal crackers, fruit newtons|
Scoring: (__* 2) + (__*1) + (__0)=
Once you have completed the questionnaire, count the number of circles in each column and calculate your score as follows: multiply the number of choices in the left-hand (high-fat) column by 2 and multiply the number of choices in the middle by 1. Any number of choices in the right-hand column will equal 0.
- Less than 10= Excellent fat habits
- 10 to 20 = Good fat habits
- 20 to 30 = Need to trim some fat
- Over 30 = very high fat diet
If your score is 20 or above, try to substitute more foods from the middle (medium fat) column or, better still, the right (low fat) column for foods in the left-hand (high fat) column.
However, after an extensive investigation, the relationship between the intake of dietary cholesterol and serum cholesterol levels remains unclear8.
Nevertheless, most doctors still recommended that people restrict their dietary intake of cholesterol to 300 mg or less per day, reduce total fat and saturated fat intake, and exercise regularly.
High-cholesterol foods include whole milk, shellfish, animal fat, and egg yolks. Only foods of animal origin can contain cholesterol.
Thus, labels that appear on foods such as peanut butter and margarine trumpeting “cholesterol-free” are overstating the obvious.
It should be noted, however, that even foods high in cholesterol, such as shellfish, may provide other important nutrients and, therefore, could remain in a healthy diet but on a more modest basis.
Reflecting our growing concern about the role of dietary fats in many health problems has been the explosion of fat-free, low-fat, or reduced-fat food items appearing in stores and restaurants.
As favorable as this trend might be, however, it is important to remember that these food items may still be high in calories and, therefore, should not be consumed in large amounts just because of their lower-fat formulation.
Newly developed fat-free products containing fat substitutes (Simplesse, simple Pleasures, Olestra, and Trailblazer) are available or soon to be available in the marketplace.
At the time of this writing, products containing Olestra (marketed as Olean), such as MAX snacks by Frito-Lay and Fat-Free Pringles, have been well received in test-marketed areas and will be distributed nationwide shortly.
These new products contain no cholesterol and have 80 percent fewer calories than similar products made with fat. Although Olestra-containing items appeared first in snack foods such as those just mentioned, it will soon be much more widely used.
New fat-free products containing Olestra-like substitutes will range from foods such as ice cream, salad dressing, cheese spreads, and yogurt to cakes, pies, and french fries9.
The development of Olestra, as an example, required more than twenty-five years and $200 million on the part of Proctor & Gamble, as an array of new technologies were required.
In general, fat-free substitutes are made through processes called micro articulation, in which several fatty acids are bonded to a sugar molecule to create a triglyceride-like molecule that imparts all of the characteristics of fats but is incapable of being enzymatically broken down by the body as are the triglycerides9.
In spite of the apparent desirability of the fat-free technology, some people have raised concerns regarding the inability of these “nouveau fats” to carry fat-soluble vitamins (vitamins A, D, E, and K).
Additional concern over side effects in some people, such as abdominal cramping, loose stools, anal leakage, and an unpleasant aftertaste, has also been raised.
One consumer group, the Center for Science in the Public Interest, has requested that the FDA rescind its approval of Olestra9.
A member of the FDA’s advisory panel also expressed concern about Olean’s safety 10. At this time only a warning label describing the side effects must appear on products made on with Olean.
The tern protein is derived from a word meaning “first importance.” Proteins are manufactured in every living cell; they are composed of chains of amino acids. Amino acids are the “bricks” from which the body constructs its own protein.
Twenty amino acids are used in various combinations to build the proteins required for physiological processes to continue in a healthy manner.
The human body obtains amino acids from two sources-by breakings down protein from food (as if to take a brick wall apart for its bricks) or by manufacturing its own bricks (amino acids) within its cells.
The latter process is less than fully successful because only eleven of the necessary twenty amino acids can be built by the body are called essential amino acids (indispensable amino acids) because they must be obtained from outside the body through the protein in food.
The eleven amino acids that the body itself can make are called nonessential amino acids (dispensable amino acids) because the body does not have to rely solely on food protein to obtain this bricks6.
In terms of food sources of amino acids, foods can be classified into one of two types, depending on whether they can supply the body with the essential amino acids or not.
Complete protein foods contain all nine essential amino acids within their protein and are of animal origin (milk, meat, cheese, and eggs).
The incomplete protein foods do not contain all of the essential amino acids and are of plant origin (vegetables, grains, and legumes [peas or beans, including chickpeas, butter beans, and tofu]).
For some people, including vegan vegetarians, people with limited access to animal-based food sources, or those who have significantly limited their meat, egg, and dairy product consumption, it is important to understand how essential amino acids can be obtained from incomplete various sources of incomplete protein foods to achieve complete sources.
This requires the careful selection of plant foods in combinations that will provide all of the essential amino acids.
The list below shows many usable combinations that include legumes and grains:
- Sunflower seeds/green peas
- Navy beans/barley
- Green peas/corn
- Red beans/rice
- Sesame seeds/soybeans
- Black-eyed peas/ rice and peanuts
- Green peas/rice
- Corn/pinto beans
When even one essential amino acid is missing from the diet, deficiency can develop.
Protein serves primarily to promote the growth and maintenance of body tissue. However, when calorie intake falls, the protein will be broken down for glucose.
This loss of protein can impede the growth and repair of tissue. From this, it can be seen that adequate carbohydrate intake prevents the protein from serving as an energy source6.
Protein also is a primary component of enzyme and hormone structure; it helps maintain the acid-base balance of our bodies and serves as a source of energy (four calories per gram consumed).
Nutritionists recommend that 15 percent of our caloric intake be from protein. Malnutrition is the world’s underdeveloped countries is often seen in the protein deficiency disease called kwashiorkor. This disease is rarely seen in countries that have an abundant supply of protein.
Vitamins are organic compounds that are required in small amounts for normal growth. reproduction, and maintenance of health.
Best vitamins differ from carbohydrates, fats, and proteins because they do not provide calories or serve as structural elements for our bodies.
Vitamins serve as coenzymes. By facilitating the action of enzymes, vitamins help initiate a wide variety of body responses and the growth of healthy tissue.
Discovered just after the turn of the twentieth century, vitamins can be classified as water-soluble (capable of being dissolved in water) or fat-soluble (capable of being dissolved in fat or lipid tissue).
Water-soluble vitamin C. Most of the excess of these water-soluble vitamins is eliminated from the body during urination.
The fat-soluble vitamins are A, D, E, and K. These vitamins are stored in the body in the adipose tissue or fat with excessive intake. It is, therefore, possible to consume and retain too many of these vitamins, particularly A and D.
Table 5-1 shows that all of the fat-soluble vitamins hold the potential for toxicity if taken in amounts that far exceed recommended dietary allowances (RDAs) (see Table 5-2A, B, and C).
Most toxicity results from the use of supplements by adults or through excessive food intake of particular sources in very small children. When toxicity develops, the condition is referred to as hypervitaminosis.
The extent to which toxicity from water-soluble vitamins can occur is somewhat open to debate.
As seen in Table 5-3, some of the water-soluble vitamins (niacin, B6, and c) have been associated with toxic effects when taken in megadoses. For adults, intake of this level would occur only through the excessive use of supplements.
Because water-soluble vitamins dissolve rather quickly in water, you should be cautious in the preparation of fresh fruits and vegetables are steamed or boiled, the more water-soluble vitamins will be lost.
Even soaking sliced fresh fruit or vegetables can result in the loss of vitamins C and B-complex vitamins. Health experts recommended that people drink (or use in cooking) any water in which fresh vegetable was boiled or steamed.
To ensure an adequate vitamin intake, do not rely on bottled vitamins sold in grocery or health food stores. The best way is really the simplest and least expensive way: Eat a variety of foods.
Unless there are special circumstances, such as pregnancy, infancy, or an existing health problem, virtually everyone in our society who eats a reasonably well-rounded diet consumes appropriate levels of all vitamins.
In spite of the availability of vitamin-rich foods, not all people eat a balanced diet based on a variety of foods.
Also, recent studies suggest that a some-what higher intake of vitamins A, C, and E for adults, and folacin (folic acid) before and during pregnancy, might have a positive effect in reducing the risk of developing cancer, atherosclerosis, birth defects, and depressed levels of HDL cholesterol (see details high protein foods).11,12 In addition, consumption of adequate amounts of folic acid before and during pregnancy has been shown to reduce the incidence of neural tube birth defects.
13 To date, most of these findings have not been translated into specific recommendations, but they are drawing increased interest on the part of both the scientific community and the general public. Clearly, the antioxidation properties of vitamins A, C, and E most keenly interest health experts today.
At the same time that many health experts are reconsidering recommendations concerning additional consumption of vitamins, the Food and Drug Administration (FDA) has implemented strict new requirements on the labeling of food supplements regarding unsubstantiated claims for the cure or prevention of disease14.
Not surprisingly, the manufacturers of these products attempted to curtail this action by strongly suggesting to consumers that the FDA planned to take vitamins off the OTC market and make them available by prescription only. Of course, this has not happened.
Today the sale of supplements (vitamins, minerals, and amino acids) is a huge industry, with 75 million Americans using dietary aids at an annual cost of more than $1.5 billion.
- Protein compounds composed of chains of amino acids; primary components of muscle and connective tissue.
- Amino acids the building blocks of protein; manufactured by the body or obtained from dietary sources.
- Vitamins organic compounds that facilitate the action of enzymes.
- Enzymes organic substances that control the rate of physiological reactions but are not altered in the process.
- Hypervitaminosis excessive accumulation of vitamins within the body; associated with the fat-soluble vitamins.
The Fat-Soluble Vitamins, Their Functions, Deficiency Conditions, and Food Sources
|Vitamin||Major Functions||Deficiency Symptoms||People Most at Risk||Dietary Sources||RDA||Toxicity Symptoms|
|Vitamin A (retinoids) and Provitamin A (carotenoids)||1. Vision, light, and color|
3.Prevents drying of skin and eyes
4.Promotes resistance to bacterial infection
|1.Night blindness 2.Xerophthalmia |
4.Dry skin (keratinization)
|people in poverty, especially preschool children (still very rare)||Vitamin A Liver Fortified milk Provitamin A Sweet potatoes Spinach Greens Carrots Cantaloupe Apricots Broccoli||Women: 800 RE (4000 IU) Men: 1000 RE (5000 IU)||Fetal malformations, hair loss, skin changes, pain in bones|
|Vitamin D (cholecalciferol and ergocalciferol)||1.Facilitates absorption of calcium and phosphorus |
2.Maintains optimum calcification of bone
|Breastfed infants, elderly shut-ins||Vitamin D- fortified milk Fish oils Tuna fish Salmon||5-10 micrograms (200-400 IU)||Growth retardation, kidney damage, calcium deposits in soft tissue|
|Vitamin E (tocopherols, tocotrienols)||1.Antioxidant: prevents the breakdown of vitamin A and unsaturated fatty acids||1.Hemolysis of red blood cells |
|People with poor fat absorption (still very rare)||Vegetable oils Some greens Some fruits||Women: 8 a-tocopherol equivalents Men: 10 a-tocopherol equivalents||Muscle weakness, headaches, fatigue, nausea, inhibition of vitamin K metabolism|
|Vitamin K (phylloquinone and menaquinone)||1.Helps prothrombin and other factors for blood clotting||1.Hemorrhage||People taking antibiotics for months at a time||Green vegetable Liver||60-80 micrograms||Anemia and jaundice|
RE, Retinol equivalents; IU, international units.
Adult Recommended Dietary Allowances,1 Revised 1989
|Lactating||1st 6 Months|
2nd 6 Months
- 1The allowances, expressed as average daily intakes over time, are intended to provide for individual variations among most normal people as they live in the United States under usual environment stresses. Diets should be based on a variety of common foods to provide nutrients for which human requirements have been less well defined. See text for a detailed discussion of allowances and of nutrients not tabulated.
- 2Weights and heights of reference adults are actual medians for the U.S. population of the designated age, as reported by NHANES II. The use of these figures does not imply that the height-to-weight ratios are ideal.
|WATER SOLUBLE VITAMINS||MINERALS|
- 3Retinol equivalents. 1 retinol=1 ug retinol or 6 GB-carotene.
- 4As cholecalciferol. 10 ug cholecalciferol= 400 IU of vitamin D.
- 5a-Tocopherol equivalents. 1 mg d-a tocopherol= 1 a-TE.
- 6 1 NE (niacin equivalent) is equal to 1 mg of niacin or 60 mg of dietary tryptophan.
Estimated Safe and Adequate Daily Dietary Intakes (ESADDIs) of Selected Vitamins and Minerals for Adults*
|Biotin (ug)||Pantothenic acid (mg)||Copper (mg)||Manganese (mg)||Fluoride (mg)||Chromium (mg)||Molybdenum (ug)|
- Because there is less information on which to base allowances, these figures are not given in the main table of RDAs and are provided here in the form of ranges of recommended intakes.
- +Because the toxic levels for many trace elements may be only several times the usual intake, the upper levels for the trace elements given in this table should not be habitually exceeded.
Estimated Minimum Sodium, Chloride, and Potassium Requirements of Healthy people*
|Age||Weight (kg)*||Sodium (mg)*+||Chloride (mg)*+||Potassium (mg)++|
- *No allowance has been included for large, prolonged losses from the skin through sweat.
- +There is no evidence that higher intakes confer any health benefit.
- ++Desirable intakes of potassium considerably exceed these values (~3500 mg for adults).
- $$No allowance included for growth. Values for those below 18 years assume a growth rate at the 50th percentile, reported by the National Center for Health Statistics and averaged for men and women.
The Water-Soluble Vitamins, Their Functions, Deficiency Conditions, and Food Sources
|Vitamin||Major Functions||Deficiency Symptoms||People Most at Risk||Dietary Sources||RDA or ESADDI||Toxicity|
|Thiamin||Coenzyme involved with enzymes in the carbohydrate metabolism; nerve function||Beriberi, nervous tingling, poor coordination, edema, heart changes, weakness||People with alcoholism, people in poverty||Sunflower seeds, pork, whole, and enriched grains, dried beans, peas, brewer’s yeast||1.1-1.5 milligrams||None possible from food|
|Riboflavin||Coenzyme involved in energy metabolism||Inflammation of mouth and tongue, cracks at corners of the mouth, eye disorders||Possibly people on certain medications if no dairy products consumed||Milk, mushrooms, spinach, liver, enriched grains||1.2-1.7 milligrams||None reported|
|Niacin||Coenzyme involved in energy metabolism. fat synthesis, fat breakdown||Pellagra, diarrhea, dermatitis, dementia||People in severe poverty where corn is dominant food, people with alcoholism||Mushrooms, bran, tuna, salmon, chicken, beef, liver, peanuts, enriched grains||15-19 milligrams||Flushing of skin at >100 milligrams|
|Pantothenic acid||Coenzyme involved in energy metabolism, fat synthesis, fat breakdown||Using an antagonist causes tingling in hands, fatigue, headache, nausea||People with alcoholism||Mushrooms, liver, broccoli, eggs; most foods have some||4-7 milligrams||None|
|Biotin||Coenzyme involved in glucose production, fat synthesis||Dermatitis, tongue soreness, anemia, depression||People with alcoholism||Cheese, egg yolks, cauliflower, peanut butter, liver||30-100 micrograms||Unknown|
Nearly 5 percent of the body is composed of inorganic materials, the minerals. Minerals function primarily as structural elements ( in teeth, muscles, hemoglobin, and thyroid hormones.)
They are also critical in the regulation of a number of body processes, including, cell membrane permeability, muscle contraction, heart function, blood clotting, protein synthesis, and red blood cell synthesis.
Approximately twenty-one minerals have been recognized as being essential minerals for human health6.
Macronutrients (major minerals ) are those minerals that are seen in relatively high amounts in our body tissues. Examples of macronutrients are calcium, phosphorus, sulfur, sodium, potassium, and magnesium.
Examples of micronutrients, minerals seen in relatively small amounts in body tissues, include zinc, iron, copper, selenium, and iodine.
Although micronutrients (trace elements) are required only in small quantities, they are still essential for good health. (See Tables 5-4 and 5-5 for listings of minerals and their functions.)
As with vitamins, the safest, most appropriate way to receive a sufficient amount of all necessary minerals is to eat a balanced diet.
Trace elements minerals whose presence in the body occurs in very small amounts; micronutrient elements.
|Vitamin||Major Functions||Deficiency Symptoms||People Most at Risk||Dietary Sources||RDA or ESADDI||Toxicity|
|Vitamin B6, pyridoxine, and other forms||Coenzyme involved in protein metabolism, neurotransmitter synthesis, hemoglobin synthesis many other functions||Headache, anemia, convulsions, nausea, vomiting, flaky skin, sore tongue||Adolescent and adult women, people on certain medications, people with alcoholism||Animal protein foods, spinach, broccoli, bananas, salmon, sunflower seeds||1.8-2 milligrams||Nerve destruction at doses>100 milligrams|
|Folate (folic acid)||Coenzyme involved in DNA synthesis||Megaloblastic anemia, inflammation of tongue diarrhea, poor growth, mental disorders||People with alcoholism, pregnant women, people taking certain medications||Green leafy vegetables, orange juice, organ meats. sprouts, sunflower seeds||180-200 micrograms||None, nonprescription vitamin dosage is controlled by FDA|
|Vitamin B12 (cobalamins)||Coenzyme involved in folate metabolism, nerve function||Macrocytic anemia, poor nerve function||Elderly because of poor absorption, vegans||Animal foods, especially organ meats, oysters, clams (B12 not plant foods)||2 micrograms||None|
|Vitamin C (ascorbic acid)||Collagen synthesis, hormone synthesis, neurotransmitter synthesis||Scurvy: poor wound healing, pinpoint hemorrhages, bleeding gums, edema||People with alcoholism, elderly men living alone||Citrus fruits, strawberries, broccoli, greens||60 milligrams||Doses>1-2 grams cause diarrhea and can alter some diagnostic tests|
Key Trace Minerals
|Mineral||Major Functions||Deficiency Symptoms||People Most at Risk||RDA or ESADDI||Nutrient-Dense Dietary Sources||Results of Toxicity|
|Iron||Part of hemoglobin and other key compounds used in respiration; used for immune function||Low serum iron levels, small, pale red blood cells, low blood hemoglobin values||Infants, preschool children, adolescents, women in childbearing years||Men: 10 milligrams Women: 15 milligrams||Meats, spinach, seafood, broccoli, peas, bran, enriched bread||Toxicity is seen in children who consume 200-400 milligrams in iron pills and in people with hemochromatosis; in this latter case, people over-absorb iron|
|Zinc||Over 200 enzymes need zinc, including enzymes involved in growth, immunity, alcohol metabolism, sexual development, and reproduction||Skin rash, diarrhea, decreased appetite and sense of taste, hair loss, poor growth and development, poor wound healing||Vegetarians, women in general, the elderly||Men: 15 milligrams Women: 12 milligrams||Seafood, meats, greens, whole grains||Reduces iron and copper absorption; can cause diarrhea, cramps, and depressed immune function|
|Selenium||Part of the antioxidant system||Muscle pain, muscle weakness, heart disease||Unknown||55-70 micrograms||Meats, eggs, fish, seafood, whole grains||Nausea, vomiting, hair loss, weakness, liver disease|
|Iodide||Part of thyroid hormone||Goiter, poor growth in infancy when the mother is deficient in pregnancy||None in America, since salt is usually fortified||150 micrograms||Iodized salt, white bread, saltwater fish, dairy products||Inhibition of function of the thyroid gland|
|Copper||Aids in iron metabolism works with many enzymes, such as those involved in protein metabolism and hormone synthesis||Anemia, low white blood cell count, poor growth||Infants recovering from malnutrition, people who use overzealous supplementation of zinc||1.5-3 milligrams||Liver, cocoa, beans, nuts, whole grains, dried fruits||Vomiting, nervous system disorders|
Key Trace Minerals— Continued
|Mineral||Major Functions||Deficiency Symptoms||People Most at Risk||RDA or ESADDI||Nutrient-Dense Dietary Sources||Results of Toxicity|
|Fluoride||Increases resistance of tooth enamel to dental caries||Increased risk of dental caries||The area where water is not fluoridated and dental treatment do not make up for this lack of fluoride||1.5-4 milligrams||Fluoridated water, toothpaste, dental treatments, tea, seaweed||Stomach upset, mottling (staining) of teeth during development|
|Chromium||Enhances blood glucose levels||High blood glucose levels after eating||People on total parenteral nutrition and perhaps elderly people with non-insulin-dependent diabetes mellitus||50-200 micrograms||Eggs yolks, whole grains, pork||Caused by industrial contamination, not dietary excess|
|Manganese||Aids action of some enzymes, such as those involved in carbohydrate metabolism||None in humans||Unknown||2-5 milligrams||Nuts, rice, oats, beans||Unknown in humans|
|Molybdenum||Aids in the action of some enzymes||None in humans||Unknown||75-250 microgram||Beans, grains, nuts||Unknown in humans|
Water and the Major Minerals
|Name||Major Functions||Deficiency Symptoms||People Most at Risk||RDA of Minimum Requirement||Nutrient-Dense Dietary Sources||Results of Toxicity|
|Water||Medium for chemical reactions, removal of waste products, perspiration to cool the body||Thirst, muscle weakness, poor endurance||Infants with a fever, elderly in nursing homes||1 milliliter per calorie burned*||As such and in foods||Probably occurs only in mental disorders: headache, blurred vision, convulsions|
|Sodium||A major ion of the extracellular fluid; nerve impulse transmission||Muscle cramps||People who severely restrict sodium to lower blood pressure (250-500 milligrams/ day)||500 milligrams||Table salt, processed foods||High blood pressure in susceptible individuals|
*An approximation; best to keep urine volume greater than 1 liter (4 cups) per day.
Water and the Major Minerals —Continued
|Name||Major Functions||Deficiency Symptoms||People Most at Risk||RDA or Minimum Requirement||Nutrient-Dense Dietary Sources||Results of Toxicity|
|Potassium||A major ion of intracellular fluid; nerve impulse transmission||Irregular heartbeat, loss of appetite, muscle cramps||People who use potassium-wasting diuretics or have poor diets, as seen in poverty and with alcoholism||2000 milligrams||Spinach, squash, bananas, orange juice, other vegetables and fruits, milk||Slowing of the heartbeat; seen in kidney failure|
|Chloride||A major ion of the extracellular fluid; acid production in the stomach; nerve transmission||Convulsions in infants||No one, probably, when infant formula manufacturers control product quality adequately||700 milligrams||Table salt, some vegetables||High blood pressure in susceptible people when combined with sodium|
|Calcium||Bone and tooth strength; blood clotting; nerve impulse transmission; muscle contractions; cell regulation||Poor increase the risk for osteoporosis||Women in general, especially those who constantly restrict their energy intake and consume few dairy products||800 milligrams (older than 24 years old)||Dairy products, canned fish, leafy vegetables, tofu, fortified orange juice||Very high intakes may cause kidney stones in susceptible people|
|Phosphorus||Bone and tooth strength; part of various metabolic compounds; major ion of intracellular fluid||Probably none, poor bone maintenance possible||Elderly consuming very nutrient-poor diets, possibly vegetarians and those with alcoholism||800 milligrams (older than 24 years)||Dairy products, processed foods, fish, soft drinks||Hampers bone health in people with kidney failure; poor bone mineralization if calcium intakes are low|
|Magnesium||Bone strength; enzyme function, nerve and heart function||Weakness, muscle pain, poor heart function||People on thiazide diuretics, women in general||Men: 350 milligrams Women: 280 milligrams||Wheat bran, green vegetable nuts, chocolate||Causes weakness in people with kidney failure|
|Sulfur||Part of vitamins and amino acids; acid-base balance||None||People who do not meet their protein needs||None||Protein food||None likely|
Water may well be our most essential nutrient since without water most people would die from dehydration effects in less than a week. people could survive for weeks and even years without some of the essential minerals and vitamins. More than half the body’s weight comes from water.
Water provides the medium for nutrient and waste transport and temperature control and plays a key role in nearly all of the body’s biochemical reactions. A common indication of inadequate fluid intake is strained, uncomfortable bowel movements.
Most people seldom think about the importance of an adequate intake of water and fluids. Adults require about six to ten glasses a day, depending on their exercise level and environment.
People who drink beverages that tend to dehydrate the body (tea, coffee, and alcohol) should increase their water consumption.
Of course, people also obtain needed fluids from fruits, vegetables, fruit and vegetable juices, milk, and noncaffeinated soft drinks. The latter are important sources of fluids because of the tendency of Americans to consume more of these beverages than they do water.
Although not considered a nutrient by definition, fiber is an important component of sound nutrition. Fiber consists of plant material that is not digested but rather moves through the digestive tract and out of the body. Cereal, fruits, and vegetables all provide us with dietary fiber.
Fiber can be classified into two large groups on the basis of water solubility. Insoluble fibers are those that can absorb water from the intestinal tract.
By absorbing water, the insoluble fibers give the stool bulk and decrease the time it takes the stool bulk and decrease the time it takes the stool to move through the digestive tract.
In contrast, soluble fiber turns to a “gel” within the intestinal tract and in so doing binds to liver bile, which has cholesterol attached. Thus, soluble fiber is valuable in removing (or lowering) blood cholesterol levels15.
Also, since foods high in soluble fiber are generally low in sugar and saturated fats, fiber may indirectly contribute to keeping blood sugar low and reduce the risk of cancer associated with diets high in saturated fats.
In recent years attention has been directed towered three forms of soluble fiber-oat bran, psyllium (from the forms plantain), and rice bran- for their ability to lower blood cholesterol levels. The sale of products containing oat bran, such as cereals and baked goods, has increased greatly since 1987.
In fact, in 1997 oat fiber was deemed effective enough to alter packaging labels in a manner reflecting its supportive role in the prevention of heart disease 16.
To accomplish a five- to six- point lowering in cholesterol, daily consumption of oat bran equaling a large bowl of oat bran cold cereal or three or more packs of instant oatmeal would be necessary.
Of course, oatmeal can be eaten as a cooked cereal or used in other foods, such as hamburgers, pancakes, or meatloaf. The role of psyllium and rice bran in lowering cholesterol levels is less well established.
Psyllium can be obtained by using laxatives such as Metamucil, Citrucel, Konsyl, Fiberall fiber wafers, Mondame, and Perdiem fiber.
The Absorption of Nutrients
In a very real sense, food ( as nutrients) is not “ in the body” until it is digested and then absorbed into and through the walls of the gastrointestinal (GI) tract, into the bloodstream, and is distributed to the cell sites at which it will be used for energy, growth, repair, and regulation.
Figure 5-2 depicts a highly diagrammatic representation of the GI tract showing specific absorption sites for several important nutrients.
The first 18 inches of the small intestine is the most active site for absorption, surpassing the level of activity in the remainder of the small intestine, the large intestine, and stomach.
It is also important to note that some portion of the alcohol contained in alcoholic drinks enters the body through the stomach wall (more in women than in men), although most are absorbed in the small intestine.
Water and salts are principally regulated by the walls of the large intestine. In light of the importance of the small intestine, any injury or disease in this location could seriously harm nutritional status by impairing the body’s ability to obtain nutrients.
In fact, in extreme cases of obesity (morbid obesity), a portion of the small intestine is resected (cutaway) in an attempt to restrict the movement of nutrients into the body.
This drastic approach to weight loss is, of course, a double-edged sword in that many nutrients needed for overall health must then be supplemented, often for the rest of the person’s life.
The Food Groups
As already mentioned, the most effective way to take in adequate amounts of nutrients is to eat a balanced diet, that is, to eat a diet that includes selections from different food groups ( see Table 5-6). Today, the United States Department of Agriculture (USDA)
Food Guide pyramid outlines five groups for which recommendations have been established and an additional group (fats, oils, and sweets ) for which no specific recommendations exist
(Figure 503). Table 506 summarizes the major nutrients each food group supplies. To determine whether you are eating a healthful diet balanced with choices from each food group, complete the personal Assessment.
- Dehydration abnormal depletion of fluids from the body; severe dehydration can lead to death.
- Fiber cellulose-based plant material that cannot be digested; found in cereal, fruits, and vegetables.
- Balanced diet a diet featuring food selections from each food group.
Figure 5-2 Important sites of nutrient absorption along the gastrointestinal tract. The size of the arrow indicates the relative amounts of absorption at that site. (Note that this drawing depicts the GI tract as being “uncoiled” to simplify the presentation of its absorption sites.)
Two to four daily servings from the fruit group are recommended for an adult. The important function of this group is to provide vitamin A, vitamin C, complex carbohydrates, and fiber in our diets.
The American Cancer Society indicates that this food group may play an important role in the prevention of certain forms of cancer. Included foods are citrus fruits and fruit juices. At least one serving high in vitamin C should be eaten daily.
Two to four servings per day are recommended. One serving is equivalent to one medium apple, banana, or orange; ½ cup of chopped, cooked, or canned fruit; or ¾ cup of fruit juice.
Guide to Daily Food Choices
|Food Group||Serving||Major Contributions||Foods and Serving Size*|
|Milk, yogurt, and cheese||2 (adult+)|
3 (children, teens, young adults, and pregnant or lactating women)
|Calcium Riboflavin Protein Potassium Zinc||1 cup milk|
1 ½ oz cheese
2 oz processed cheese
1 cup yogurt
2 cups of cottage cheese
1 cup custard/pudding
1 ½ cups ice cream
|Meat, poultry, fish, dry beans, eggs, and nuts||2-3||Protein Niacin Iron Vitamin B6|
|2-3 oz cooked meat, poultry, fish|
1 – ½ cups cooked dry beans
4t peanut butter
½ -1 cup nuts
|Fruits||2-4||Vitamin C |
|¼ cup of dried fruit|
½ cup cooked fruit
¾ cup juice
1 whole piece of fruit
1 melon wedge
|½ cup raw or cooked vegetables|
1 cup of raw leafy vegetables
|Bread, cereals, rice, and pasta||6-11||Starch|
Magnesium | |
Fiber | |
Zinc | |
|1 slice of bread|
1 oz ready-to-eat cereal
½ – ¾ cup cooked cereal, rice, or pasta
|Fats, oils, and sweets||Foods from this group should not replace any of the other groups. Amounts consumed should be determined by individual energy needs|
|This is a practical way to turn the RDA into food choices. You can get all the essential nutrients by eating a balanced variety of foods each day from the food groups listed here. Eat a variety of foods in each food s in each food group, and adjust serving sizes appropriately to reach and maintain a desirable weight.|
- *Maybe reduced for children’s servings.
- +>25 years of age.
- ++Only in animal food choices.
- | | Whole grains especially.
- $ If enriched.
Three to five servings from the vegetable group are recommended for an adult. As with the fruit group, the important function of this group is to provide vitamin A, vitamin C, complex carbohydrates, and fiber.
The American Cancer Society suggests that this food group may also be important in the prevention of some cancers. Food included in this group are dark green, yellow, and orange vegetables, canned or cooked vegetables, and tossed salads.
At least one serving of a dark green, yellow, or orange vegetable containing fat-soluble vitamin A should be consumed every other day.
Cruciferous vegetables, such as broccoli, cabbage, brussels sprouts, and cauliflower, may be especially helpful in the prevention of certain forms of cancer17. On the basis of current recommendations, people should include three to five servings per day in their diets.
One serving consists of 1 cup of raw, leafy vegetables, ½ cup of vegetables, cooked or chopped raw, or ¾ cup of vegetable juice.
A recent study of young people from two years of age to eighteen years found only 20 percent meet this recommendation and that 25 percent of all the vegetables consumed was in the form of french fries18.
Figure 5-3 The USDA Food Guide Pyramid.
Milk, Cheese, and Yogurt
The milk, cheese, and yogurt group contribute two primary nutritional benefits: high-quality protein and calcium (required for bone and tooth development). Foods included in this group are whole milk, low-fat milk, yogurt, cheese, and ice cream.
The adult recommendation is two to three cups of milk or two to three equivalent servings from this group each day. For teenagers, the recommendation is four cups of milk each day.
Recently, some physicians have begun recommending that premenopausal women consume three to four servings from this group to provide maximal protection from osteoporosis (see details meat and mixed).
One serving equals 1 cup of milk or yogurt, 1.5 ounces of natural cheese, or 2 ounces of processed cheese. Because of the general concern over saturated fat, cholesterol, and additional calories, low-fat milk products are recommended in place of high-fat milk products.
In November of 1996, the FDA released new, more consumer-friendly labels for some milk products. For example, 2 percent milk must now be labeled reduced-fat milk instead of low-fat milk, while skim milk may also be called fat free, nonfat, no fat, zero fat, without fat, negligible source of fat, or insignificant source of fat 14.
Meat, Poultry, Fish, Eggs, Dry Beans, and Nuts
Our need for daily selections from this protein-rich group is based on our daily need for protein, iron, and B vitamins. Meats include all red meat (beef, pork, and game), fish, and poultry. Meat substitutes include cheese, dried peas and beans (legumes), and peanut butter.
Eggs can also be used as meat substitutes; however, using only the separated eggs whites provides an excellent source of protein without the accompanying fat, including cholesterol.
The current recommendation for an adult is four ounces total meat, poultry, or fish per day, preferably in two to three servings. However, some nutrition specialists suggest one serving per day (or every other day), with the use of legumes as a protein supplement.
One serving from this group consists of two to three ounces of cooked lean meat, poultry, or fish. One-half cup of cooked dry beans or one egg counts as one ounce of lean meat. Two tablespoons of peanut butter or one-third cup of nuts also count as one ounce of meat.
If people select foods that fit into both the meat and the milk categories, they must be careful to include these foods in only one category for that particular day.
Also, it is important that meat and fish are fresh, stored appropriately, and cooked adequately to reduce the likelihood of serious food-borne illnesses. The Health Action Guide on this page lists the USDA guidelines for sale handing of meat.
The fat content of meat varies considerably. Some forms of meat yield only 1 percent fat, whereas others may be as high as 40 percent fat. Poultry and fish are generally significantly lower in overall fat than are red meats.
Interestingly, the higher the grade of red meat, the more fat will be marbled throughout the muscle fiber and the higher will be its fat and caloric content. Indeed, the higher grade steak usually tastes better, but that is because of its higher fat content.
Meats are generally excellent sources of iron. Iron is present in much greater amounts in red meats and organ meats (liver, kidney, and heart) than in poultry and fish. Iron plays a critically important role in hemoglobin synthesis on red blood cells and, thus, is an important contributor to physical fitness and overall cardiovascular health. cruciferous vegetables (crew if er us) vegetables that have flowers with four leaves in the pattern of a cross.
Vegetables provide vitamins, complex carbohydrates, and fiber and may help prevent some types of cancer. Are you eating three to five servings a day?
Seven-Day Diet Study
A primary requirement for good nutrition is a balanced diet. A variety of food selections forms the basis of this diet. For a 7-day period, assign yourself the points indicated when each dietary requirement is met.
Record your points in the appropriate column for each day. Total your daily and weekly points. Negative points for junk food consumption should be subtracted from your daily and weekly totals.
|Milk and milk products|
One cup of milk or equivalent
Second cup of milk
The third cup of milk
One serving of eggs, meat, fish, poultry cheese, dried beans, or peas.
One or two additi0onal serving of eggs, meat fish, poultry, or cheese
|Fruits and vegetables|
One serving of green or yellow vegetables
One serving of citrus fruit, tomato, or cabbage
Two or more serving of other fruits and vegetables, including potatoes
|Bread and cereals|
Four or more serving of whole-grain or enriched cereal or bread
|Junk foods (or negative point value foods) Sweet rolls|
Potato chips, corn chips, or cheese curls
|Weekly point total||600-700 Excellent dietary practices|
|Negative point total||450-599 Adequate dietary practices|
|The adjusted weekly point total||300-449 Marginal dietary practices|
|Below 300 Poor dietary practices|
Bread, Cereals, Rice, and Pasta
The nutritional benefit from the bread, cereals, rice, and pasta group lies in its contribution to B-complex vitamins and energy from its complex carbohydrates.
Some nutritionists believe that the use of foods from this group promotes protein intake since many foods in this group are prepared as complete-protein foods, such as macaroni and cheese, cereal and milk, and bread and meat sandwiches.
Six to eleven servings daily from this group are recommended. That may sound like a lot of food, but official serving sizes are small.
For example, one slice of bread, one ounce of ready-to-eat cereal, or one-half cup of cooked cereal, rice, or pasta counts as a serving, so it’s easy to eat several servings in a single meal. several daily servings of any enriched or whole-grain bread or cereal are recommended.
Milling of cereal grains into flour tends to deplete important nutrients, including fiber, vitamin B6, vitamin E, magnesium, and various trace elements. The process of enrichment returns only four of these nutrients: thiamine, niacin, riboflavin (all B vitamins), and the mineral iron.
Fortunately, whole-grain flour is a healthful alternative for most consumers, since few, if any, nutrients are lost in the milling process. The cereal germ, the fiber, and additional nutrients are not destroyed.
Fats, Oils, and Sweets
Where do such items as beer, butter, candy, colas, cookies, corn chips, and pastries fit into your diet? Today they are included under the label “ fats, oils, and sweets”.
Most of the items mentioned contribute relatively little to healthful nutrition other than providing additional calories (generally from sucrose) and significant amounts of salt and fat.
As you will, people who are salt-sensitive must reduce their salt intake as a step in preventing the development of high blood pressure. It is not surprising that many of these items are referred to collectively as junk foods.
Of course, if particular food items, such as cookies, are made from high-quality flour and contain raisins and nuts, people can receive some nutritional benefit from consuming such goodies (see the discussion of low-calorie chicken).
Understandably, the processed-food industry encourages this empty-calorie approach to eat. Many vending machines are filled with relatively expensive junk foods. Indeed, advertising for nonnutritious foods overwhelmingly exceeds advertising for nutritious foods.
Although it is difficult to recall a television commercial for lettuce, broccoli, or green beans, we can all recite advertising slogans for our favorite soft drink, alcoholic beverage, a breakfast snack, or candy bar.
It takes a lot of willpower to say no to the foods in this group. Although they are of little nutritional value themselves, they can be part of a healthy diet if eaten only sparingly.
Most fast foods have a high fat density. Can you think of alternative foods you could eat on the go if you planned ahead?
Fast foods are convenience foods usually prepared in a walk-in or drive-through restaurant. In contrast to that of junk foods, the nutritional value of fast foods can vary considerably (see details of vegan food).
As can be seen in the calories from the fat (%) column, fat density remains a serious limitation of fast foods. In comparison to the recommended standard (25% to 30% of total calories from fat), depicted in Figure 5-4, 40 percent to 50 percent of the calories in fast foods are obtained from fats.
A conversion some years ago from animal fat to vegetable oil for frying (to reduce cholesterol levels) did not alter the fat-dense nature of these foods items.
In fact, some nutritionists contend that the vegetable oil formula now used by the major fast-food companies is hydrogenated vegetable shortening and not liquid vegetable oil as advertised.
If so, this shortening contributes fat in the form of trans-fatty acids, which are suspected contributors to arterial wall damage.
On the more positive side, fast-food restaurants have broadened their menus to include whole-wheat bread and rolls, salad bars, and low-fat milk products.
Many of the larger fast-food restaurants provide nutritional information for consumers upon request or from well-stocked racks.
Perhaps, however, the most regressive step taken by the fast-food industry has been the aggressive marketing of “combination” meals in which three or four menu items are marketed for one price under a single numerical label……;
I’ll take a number #1 with a diet drink.” Further, these already sizable meals are now being supersized at an “affordable” price for those who want maximum fat, salt, and calories in a single sitting.
Of course, the driving force is profit. Extra cheese and more french fries, plus bacon to change the flavor of a meal, are inexpensive ways to raise profit margins20. Earlier attempts to make fast food more health-enhancing seem to have taken a back seat to corporate earnings.
- Enriched the process of returning to foods some of the nutritional elements (B vitamins and iron ) removed during processing.
- Fat density, the percentage of a food’s total calories that are derived from fat; above 30 percent reflects higher fat density.
Facts about Fast Foods
Will you stop at a fast-food restaurant today? Consider these points before you do: (1) Will this be an extra meal, nor have I planned for it as a part of my food intake for the day? (2) Can fast foods be part of a balanced diet? (3) Do I realize how fat-dense this meal will be? If you answer yes to these questions, then you are practicing responsible, healthful nutrition planning.
Figure 5-4 Where do your calories come from? This figure compares our present sources of calories with the sources that are currently recommended by nutritionists.
In recent years a large group of physically active components thought to be able to deactivate carcinogens or function as antioxidants have been identified in a variety of fruits and vegetables.
Among these are the carotenoids (from green vegetables), polyphenols (from onions and garlic ), indoles (from cruciferous vegetables), and the allyl sulfides (from garlic, chives, and onions ).
These phytochemicals may play an important role in reducing the risk of cancer in people who consume a large number of foods (vegetarian or semivegetarian diets) from these two food groups21.
So important are these several distinct classes of chemicals that they have been called “as essential as vitamins.”22 Whether the recommended minimum number of servings from the fruit and vegetable groups will be increased based on this new information remains to be seen.
The nostalgia some people have for the “good old days” certainly extends to our current food supply. Today many people believe that the food they consume is unhealthy because of the 2,800 generally recognized as safe (GRAS) food additives that can be put into food during production, processing, and preparation23. But should these additives be banned?
The presence of additives in the food supply is not a totally modern occurrence. Salt, spices, and the chemicals imparted during the smoke curing of meats have an altered food supply since the dawn of recorded history.
In addition, naturally occurring biological toxins and the foreign materials once added to food by processors made yesterday’s food far less than pure and natural.
Even with the state and federal inspection that exists today, thousands of substances could be incidentally introduced during production or preparation, some of which might pose a significant health threat.
However, if we wish to live in an urban setting, work outside the home, insist on convenience, and escape the limitations imposed by the seasonal nature of many foods, we will likely have to accept the presence of a considerable number of food additives.
Today’s food manufacturers add chemical compounds to the food supply for several reasons that they believe consumers support:
- To maintain the nutritional value of the food,
- To maintain the food’s freshness by preventing changes in its color, flavor, and texture,
- To contribute to the processing of the food by controlling its texture, acidity, and thickness, and
- To make the food more appealing to the consumer by enhancing its flavor and standardizing its color. Market research apparently indicates that consumers will continue to accept these alterations.
The Food Additives Amendment ( 1958) and the Color Additives Amendment (1960) to the federal Food, Drug and Cosmetic Act (1938) require that new additives to the food supply be safe for human consumption.
The process through which the manufacturer must go to gain approval is lengthy and expensive. Even compounds that have long been “generally recognized as safe” by experts are now undergoing reevaluation through modern laboratory technology.
It is hoped that all truly harmful additives will soon be identified and removed from the food supply.
Food additives chemical compounds that are intentionally or unintentionally added to our food supply.
Learning From Our Diversity Eating Ethnic-The Healthy Way
If you’re a traditional-age student, ask some older students what they are when they were growing up. You’re likely to hear a list that includes such quintessentially American favorites as meatloaf, mashed potatoes and gravy, chicken pot pie, hearty beef stew, and homemade fudge layer cake.
If you’re talking to older classmates whose heritage is largely western European, you probably won’t find many exotic dishes on their childhood food list, because twenty-five or thirty years ago, ethnic food to most people of that background meant an occasional pizza or takeout chow mein.
Big meals served “family style”, featuring red meat and lots of side dishes plus a rich dessert-were considered healthy, as well as essential for growing, active children.
What’s more in many households, being able to put a big meal on the table was a sign of prosperity- a key consideration for anyone who suffered deprivation in the Great Depression of the 1930s.
Today, as we near the end of the twentieth century, our food focus is firmly on ethnic dishes, with their novel flavors and textures, their exotic spices, their alluringly foreign names.
As we become increasingly familiar with the traditional favorites of wide range of ethnic heritages, we incorporate them into our diet- sometimes because they’re new to our jaded palates, sometimes because we want to be front and center with the current food fads, and sometimes because we read or hear that so-called ethnic foods are healthier for us than are the traditional American dishes based on meat and potatoes.
It’s true that many ethnic cuisines feature generous servings of vegetables, with just a bit of fish, meat, or poultry, plus spices, for flavor.
Dishes are often cooked with heart-healthy olive oil instead of cholesterol-heavy butter, shortening, or lard. Protein is more likely to come from legumes than from meat, and dessert may be fruit with a small wedge of cheese instead of seven-layer fudge cake or rocky road ice cream.
Good examples are the cuisines of China, the Mediterranean, and the Pacific Rim. Following such culinary traditions is indeed likely to provide us a far more healthful, balanced food intake than is the typically high-calorie diet of most Americans.
But a word of caution is in order. Too many healthy ethnic favorites have crossed the ocean to America, only to be transformed into barely recognizable versions of themselves that are loaded with the sodium, sugar, and fat we seem to crave.
In your favorite Italian ristorante, fresh vegetables and pasta are fine but ladle on the heavy cream sauce and you’re looking at a plateful of fatty calories.
Ask for garlic and a little olive oil instead, and you’ll save hundreds of calories and be able to savor the taste of every bite. In Chinese restaurants, watch out for big fat in little packages- crab Rangoon packed with cream cheese (Rangoon is in India, not China- doesn’t that make you wonder?), butterfly shrimp (fried in batter), and potstickers (tasty but bursting with fat).
Stick with fresh steamed vegetables-skip the sugary sweet and sour glaze-have a small amount of lean meat or fish, a serving of plain rice (not fried), and try eating with chopsticks.
That way you’ll have time to focus on what you’re eating and savor some unusual textures and spices-which, after all, is what “eating ethnic” is all about!
What are your favorite ethnic foods? Why do you like them? In what ways might the ethnic foods you love have been modified to appeal to American tastes?
Since 1973, food manufacturers have been required by the FDA to provide nutritional information (labels) on products to which one or more nutrients have been added or for which some nutritional claim has been made.
Despite the presence of these labels, there was concern about whether the public could understand the labels as they appeared and whether additional information was required. Accordingly, the FDA, in consultation with individual states and public interest groups, developed new labeling regulations. Revised labels began appearing on food packages in May 1993.
The newly adopted label is shown in Figure 5-5. Specific types of information contained on the new label are highlighted. Additionally, newly developed definitions for nutrition-related terms are shown in the Star Box on page 142.
Proposals for the labeling of raw foods, including fresh produce, meat, and seafood, are now being studied. Concern for consumer protection stems from recent disclosures regarding inadequate meat inspection, undercooking of hamburgers, and the risk of contaminated seafood.
Currently, single-ingredients meat, fish, and poultry products are not required to have a label. In most areas of the country, however, the standard food label is being applied. Processed meat, fish, and poultry products, such as hot dogs, fish sticks, and chicken patties, must be labeled. produce, such as vegetables and fruit, is not required to be labeled24.
Figure 5-5 Nutrition Facts panel. A Top of the panel; B, the bottom of the panel.
Guidelines for Dietary Health
For decades the American public has received dietary guidelines from a variety of professional and government groups. In each case, the intent has been to foster changes in dietary practices to reduce the risk of developing chronic disease and enhance the overall nutritional health of the public.
In most cases, these guidelines have been generated by concerns over the actual dietary practices that should be followed on the basis of scientific understanding.
Although dietary guidelines of one type or another have been issued on many occasions, the Dietary Guidelines for Americans represent the most current and widely disseminated guidelines.
The newest version appeared in 1995 as the fourth edition of Nutrition and Your Health: Dietary Guidelines for Americans3. As presently constructed, these guidelines are directed to healthy Americans two years of age and older and to health professionals who can influence the public’s dietary practices.
Information contained within these guidelines was extracted from a variety of sources, including the Surgeon general’s Report on Nutrition and Health.
The following discussion explains the specific guidelines.
Eat a variety of foods. At the very heart of these dietary guidelines, and virtually all others, is the contention that a wide variety of food from each food group is necessary for people to achieve a truly balanced diet.
When choices are limited to only a few selections from within each food group because of preference or traditional practice, the total representation of nutrients within each group can be lost, since no single selection is nutritionally complete.
- Balance the food you eat with physical activity maintains or improves your weight. The concept of energy balance (See details physical fitness program}, in which caloric intake is expended through regular physical activity rather than being placed into long-storage as adipose tissue, is central to weight management. Additionally, in the absence of this balance, excessive weight gain will increase the likelihood of developing many of the chronic conditions that are detrimental to the heath of middle-age and older adults.
- Choose a diet with plenty of grain products, vegetables, and fruits. Complex carbohydrates, fiber, vitamins, and an array of minerals are critically important for sound nutritional health. Grain products, vegetables, and fruits are excellent sources of these important types of nutrients. These foods are also sources of the plant proteins whose consumption provides the body with needed amino acids.
- Choose a diet low in fat, saturated fat, and cholesterol. Driven by several decades of research into the relationship of dietary fat, particularly saturated fat and cholesterol, to cardiovascular disease, this recommendation is of critical importance. As reported elsewhere in the chapter, careful monitoring of meat consumption and, particularly, following a vegetarian diet are excellent approaches to meeting this guideline.
- Choose a diet moderate in sugars. Sugars are simple carbohydrates that provide the body with a readily available supply of calories, which provide energy to our working muscles. Unfortunately, however, they represent empty calories in that they carry little in the way of other important nutrients.
- Additionally, when consumed excessively, they can contribute to energy imbalance, leading to weight gain. Alcoholic beverages and snack foods are principal sources of sugars and their empty calories for many college students. In contrast, the complex carbohydrates obtained by eating vegetables, fruits, and cereal grains are eventual sugar sources for the body and far more healthful than those derived directly from dietary sugars.
- Choose a diet moderate in salt and sodium. In the 10 to 115 percent of people who possess a genetically based salt sensitivity, the dietary intake of salt (our principal source of sodium) should be monitored very carefully to prevent excessive fluid accumulation in the body leading to elevated blood pressure.
- For most people, however, normal kidney function clears excessive sodium from the body, thus minimizing the increase in blood pressure seen in salt-sensitive individuals. Although nutritionists generally see little concern over “normal” dietary salt intake for nonsalt- sensitive people, recommendations such as that appearing above continue to be made.
- If you drink alcoholic beverages, do so in moderation. In light of the fact that alcohol barely qualifies as food (except as a source of empty calories), this dietary recommendation may seem out of place.
- Unfortunately for those who abuse it, perhaps no other “food” carries the same potential for both short-term and long-term health problems. In addition to the guidelines just discussed, the most recent report also contains information pertaining to recommendations for specific groups of people based on age, gender, and other factors.
This appears in the Health Action Guide
Table 5-7 shows how healthful dietary changes can lower your risk of developing certain major diseases. Whether the newest Dietary Guidelines for Americans will be more fully implanted than their predecessors remains to be seen.
Regardless, most Americans could move much closer toward meeting these guidelines. The Health Action Guide offers helpful suggestions for modifying your own diet.
Definitions of Nutrition-Related Clams
- Free: an amount that is “nutritionally trivial” and unlikely to have a physiological consequence
- Calorie-free: fewer than 5 calories a serving
- Sugar-free: less than 0.5 grams per serving
- Sodium free and salt-free: less than 5 milligrams of sodium per serving
- Fat-free than 0.5 grams of fat per serving, providing that it has no added fat or oil ingredient
- Low fat: 3 grams or less of fat per serving per 100 grams of the food
- Low in saturated fat: may be used to describe a food that contains I gram or less of saturated fat per serving and not more than 15 percent calories from saturated fat
- Cholesterol free: less than 2 milligrams of cholesterol per serving and 2 grams or less saturated fat per serving
- Low in cholesterol: 20 milligrams or less per serving and per 100 grams of food and 2 grams or less of saturated fat per serving
Recommended Dietary Adjustments
Nutritionists are concerned about some of the dietary practices among young adults. these concerns exist because as professionals in the field of nutrition they realize that dietary practices established during the college years may continue throughout life.
Of particular concern are those diets that are both unbalanced and lack the variety of food selections emphasized throughout this chapter, including may weight-reduction diets and those diets with an overreliance on fast foods and vending machine (snack) foods.
The recommendations that follow are made with knowledge that the demands of life, including college life, will continue to force some compromises in the adoption of healthful dietary patterns.
Additional Milk Consumption
Because of the tendency for older women to develop a loss in bone mass density, a condition called osteoporosis, it is recommended that adult women increase their dairy product intake to achieve the equivalent of four servings per day.
This additional intake provides needed calcium, which may reduce the incidence of hip, wrist, and vertebral fractures in the elderly adult years. Excessive caloric and fat intake can be controlled by using skim milk or low-fat yogurt and by decreasing the daily intake of all fats.
For people who do not like dairy products or who are allergic to milk, calcium supplements are an alternative. Of course, the other nutritional benefits from the milk group cannot be obtained through calcium supplements empty calories obtained from foods that lack most other important nutrients.
Recommended Dietary to Reduce the Risk of Diseases and Their Complications
|Change in Diet||Reduce Fats||Control Calories||Increase Starch* and Fiber||Reduce Sodium||Control of Alcohol|
|Reduce the risk of:|
- *Starch refers to complex carbohydrates provided by fruits, vegetables, and whole-grain products.
- +Primarily gallbladder disease (fat), diverticular disease (fiber), and cirrhosis (alcohol).
Additional Protein-Rich Sources
Premenopausal women often need to replace iron lost during menstruation. One way to do is to eat three ounces of red meat three or four times per week. Iron obtained from red meat (called heme iron) is in its most biologically available form.
A general lowering of fat intake will allow this small inclusion of red meat to be undertaken without increasing overall fat intake or adding calories.
Another way to maintain adequate iron stores is to include appropriate vegetables, fruits, and grain products in the diet. Some excellent vegetable sources of iron are lettuce, endive, beets, tomatoes, spinach, green peas, green beans, legumes, and broccoli.
Good fruit sources of iron are apricots, cantaloupe, dates, prunes, and raisins. Enriched or whole-grain bread and breakfast cereals are also good iron sources.
Milk products contain little iron. Vegetarians and others who eat little or no red meat should pay particular attention to their iron intake.
Iron supplements may help provide needed iron. However, it is a good idea to consult a physician before taking iron supplements.
Supplements alone do not provide the additional benefits found in the protein-rich food group, and they may cause severe digestive complications. In addition, iron supplements must be stored carefully because they are a leading cause of death from accidental poisoning in young children.
Additional Vitamin C and A
Foods chosen from the fruit and vegetable groups on a regular basis should include those that are good sources of vitamins C and A. The inclusion of additional vitamin C in the diet will assist in the absorption of iron from bread, cereal, and eggs.
For women of reproductive age, iron stores are an important consideration, since iron is a component of the hemoglobin found in red blood cells that are lost during menstruation.
In addition to the recommendation concerning vitamin C, larger servings of fruits and vegetables, particularly the dark green vegetables, are recommended. By increasing intake in this food group, desirable increases in folacin and vitamin A can be achieved.
Folacin’s role in intrauterine development and in preventing macrocytic anemia makes its increased presence in the diet of critical importance. High levels of carotenes found in dark green vegetable aid in the production of vitamin A, a necessary fat-soluble vitamin.
Eating more whole-grain cereals and bread can help you increase your carbohydrate and fiber intake.
Additional Grain Product Consumption
The Dietary Guidelines for Americans recommended that 60 percent of our total calories come from carbohydrates. Increasing the quality of whole-grain bread and cereals in the diet can make sure this recommendation is met.
Moderate Alcohol Consumption
The risks and benefits of alcohol use are discussed at length. However, because so many adults consume alcohol, we should indicate here that heavy use of alcoholic beverages can seriously harm nutritional status.
Alcohol provides a significant amount of empty calories. This can be an important concern for alcohol users who wish to control their weight.
Also, the overuse of alcohol can rob your body of its ability to absorb other nutrients successfully, may prevent you from consuming a healthy diet, and is associated with a wide variety of diseases, including cancer and liver complications. From a health standpoint, moderation in the use of alcohol makes a lot of sense.
For many college students, the consideration of nutrient density may prompt certain dietary adjustments. The nutrient density of a food item relates to its ability to supply proportionally more of the RDA (for select vitamins and minerals) than it does daily calorie requirements.
Foods with a high nutrient density are better choices than those that supply only empty calories. For example, a bag of potato chips or a bottle of beer has a much lower nutrient density than either a bean burrito or a slice of vegetable pizza.
Choosing to eat foods with high nutrient density is especially important for people who are trying to limit caloric intake, either for weight management or to counter the decreased caloric needs of older adulthood.
Figure 5-6 compares the nutrient density of soda to that of chocolate milk.
Vegetarian diets can be strongly recommended, particularly for people who are willing to be “good students” of nutrition. In the sections that follow, various forms of vegetarianism will be addressed.
Read carefully the Topics for Today article on best salad recipes vegetarian, which describes semi vegetarianism, a diet in which meat consumption is significantly reduced but not eliminated, and discusses the health benefits of vegetarian food guide pyramid modeled after the USDA Food Guide Pyramid.
A vegetarian diet relies on plant sources for most of the nutrients the body needs. Vegetarian diets encompass a continuum from diets that allow some animal sources of nutrients to those that not only exclude animal sources but also are restrictive even in terms of the plant sources of nutrients permitted.
We will briefly describe three vegetarian diets, beginning with the least restrictive in terms of food sources.
A. The nutrient density of chocolate milk
B. The nutrient density of soda
Figure 5-6 A comparison of the nutrient density of chocolate milk with that of soda. The bars that represent protein, vitamin A, calcium, and riboflavin are all taller than the calorie bar, showing that chocolate milk is nutrient-dense for these nutrients. B, All of the nutrient bars are shorter than the calorie bar, illustrating that soda has a low nutrient density relative to the number of calories it supplies.
- Folacin (foe la sin) folic acid; a vitamin of the B-complex group; used in the treatment of nutritional anemia.
- Macrocytic anemia (mac roe sit ick uh nee mee a)
form of anemia in which large red blood cells predominate, but in which total red blood cell count is depressed.
- Semi vegetarianism a diet that significantly reduces but does not eliminate meat consumption and allows the consumption of dairy products and eggs.
A Food pyramid for Ovolactovegetarians
- *Lactovegetarians can omit eggs from this pyramid.
- +Include one dark green or leafy variety daily.
- ++One serving of a vitamin-and mineral-enriched cereal is recommended.
- It contains about 75g of protein and 1650 calories.
- Base serving sizes on those listed for the Food Guide Pyramid.
Figure 5-7 A Food pyramid for vegetarians.
Depending on the particular pattern of consuming eggs (ova) and milk (Lacto) or using one but not the other, ovolactovegetarianism can be an extremely sound approach to healthful eating during the entire course of the adult years.
An ovolactovegetarian diet provides the body with the essential amino acids while limiting the high intake of fats seen in more conventional diets.
The exclusion of meat as a protein source lowers the total fat intake, while the consumption of milk or eggs allows for an adequate amount of saturated fat to remain in the diet.
The consistent use of vegetable products as the primary source of nutrients supports the current dietary recommendations for an increase in overall carbohydrates, an increase in complex carbohydrates, and an increase in fiber.
Meatlike products composed of textured vegetable protein is available in supermarkets. Non-meat bacon strips, hamburgers, and chicken patties, and milk sausage can be used by people who want to restrict their meat intake but still want a meat-like product. Soybeans are the primary sources of this textured vegetable protein. (See details prevent diabetes food)
Two relatively minor concerns associated with some ovolactovegetarian diets are those of zinc deficiency and the overuse of a wide variety of food supplements.
Because of zinc’s role in the body’s use of iron, ovolactovegetarians may need to take this mineral in supplement form. However, the general use of large quantities of food supplements may be harmful or, at best, unnecessary.
Lactovegetarian and Ovovegetarian Diets
People who include dairy products in their diet but no other animal products, such as eggs and meat, are lactovegetarians. As with the ovolactovegetarian diet, little risk is associated with this dietary product such as milk and cheese, yet consume eggs, are love vegetarians.
Both diets carry the advantages of ovolactovegetarianism but are a bit more demanding because of the elimination of one of the two nonmeat sources of animal products.
Vegan Vegetarian Diet
A vegan vegetarian diet is one in which not only meat but also other animal products, such as milk, cheese, and eggs, are removed from the diet. When compared with the ovolactovegetarian diet, the vegan diet requires a higher level of nutritional understanding to avoid nutritional inadequacies.
When plants are the body’s only source of nutrients, as in vegan vegetarianism, several difficulties can arise. The novice vegan will need to be particularly alert for these problems. One potential difficulty is that of obtaining all of the essential amino acids.
Since a single plant source does not contain all the essential amino acids, the vegan must learn to consistently employ a complementary diet.
By carefully combining various grains, seeds, and legumes, amino acid deficiency can be prevented. This diet probably should not be used by children, pregnant women, and lactating mothers.
In addition to the potential amino acid deficiency, the vegan could have some difficulty in maintaining the necessary intake of vitamin B12. Possible ramifications of inadequate B12 intake include depression, anemia, back pain, and menstrual irregularity.
Vegans often have difficulty maintaining adequate intakes of iron, zinc, and calcium6. Calcium intake must be monitored closely by the vegan. In addition, vitamin D deficiencies can occur. Supplements and daily exposure to sunshine will aid in maintaining adequate levels of this vitamin.
A final area of potential difficulty for the vegan is that of insufficient caloric intake because of the satiation resulting from the voluminous nature of the diet.
Early satiation caused by a large amount of fiber may lower carbohydrate intake to the point that protein stores (muscle mass) are used for energy. (See details discuss muscular fitness)
Because of its nutritional limitations, many nutritionists do not recommend the vegan vegetarian diet, even for adults.
They suggest that unless followed for reasons closely related to ecological, philosophical, or animal rights beliefs, the total exclusion of animal products seems to accomplish little from a nutritional point of view that cannot be accomplished through ovolactovegetarianism or semi vegetarianism.
High-Risk Dietary Practices
Whereas the health benefits and relatively low risks of vegetarianism make those diets attractive, the diets in the following discussion hold the potential for serious health risks.
Unbalanced and Fad Diets
Nutritionists are particularly concerned about collegiate dietary patterns that are associated with an unbalanced diet to achieve or maintain weight loss. An unbalanced diet might consist of a single food (like pizza) or food selections from just one or two of the five main food groups.
Whether you eat only grapefruit, bananas, avocados, or some other “special” foods, the point remains the same: A diet lacking variety and balance generally cannot provide you with all of the needed nutrients.
Nutritionists continue to inform us that college students, for some reason, tend to adopt these unbalanced diets more frequently than other adults.
Noticing the poor dietary practices of a friend or roommate should prompt you to look carefully at your own dietary practices (see the Personal Assessment). You should be certain that your own dietary pattern is not more unbalanced than you might have suspected.
Nutrition and the Older Adult
Nutrition needs change as adults age. Age-related alterations to the structure and function of the body are primarily responsible for this.
Included among the changes that alter nutritional requirements and practices are changes in the teeth, salivary glands, taste buds, oral muscles, gastric acid production, and peristaltic action (movement of food through the gastrointestinal tract25).
Older adults can find food less tasteful and harder to chew. Chronic constipation resulting from changes in gastrointestinal tract function can also decrease interest in eating25.
The progressive lowering of the body’s basal metabolism is another factor that eventually influences dietary patterns of older adults25. As energy requirements fall, the body gradually senses the need for less food.
This gradual recognition of lower energy needs results in lessened food intake and loss of appetite in many elderly people. Because of this decreased need for calories, the nutrient density-the nutritional value of food relative to the number of calories supplied-is an important factor for the elderly.
Besides the physiological factors that influence dietary patterns among the elderly, several psychosocial factors alter the role of food in the lives of many older adults.
Social isolation, depression, chronic alcohol consumption, loss of income, transportation limitations, and housing restrictions are factors in lifestyle patterns that can alter the ease and enjoyment associated with the preparation and consumption of food 26.
- Ovolactovegetarian a diet that excludes all meat but does allow the consumption of eggs and dairy products.
- Food supplements nutrients taken in addition to those obtained through the diet; includes powered protein, vitamins, and mineral extracts.
- a vegan vegetarian diet (vee gun) a vegetarian diet that excludes the consumption of all animal products, including eggs and dairy products.
- Lactating breastfeeding or nursing. Unbalanced diet a diet lacking adequate representation from each of the food groups.
International Nutritional Concerns
Whereas nutritional concerns in this country are centered on overnutrition, including fat density and excessive caloric intake, the main concern in many areas of the world is the limited quantity and quality of food.
Reasons for these problems are many, including the limitations imposed by weather, the availability of arable land, religious practices, political unrest, war, social infrastructure, and material and technical shortages. Underlying nearly all of these factors, however, is unabated population growth.
To increase the availability of food to countries whose demand for food outweighs their ability to produce it, a number of steps have been suggested, including the following:
- Improve the yield of land currently under cultivation.
- Increase the amount of land under cultivation.
- Improve animal production on land not suitable for cultivation.
- Use water (seas, lakes, and ponds) more efficiently for the production of food.
- Develop unconventional foods through the application of technology.
- Improve nutritional practices through education.
Little progress is being made despite impressive technological breakthroughs in agriculture and food technology (such as “miracle” rice, disease-resistant high-yield corn, and soybean-enhanced infant foods), the efforts of governmental programs, and the support of the Food and Agricultural Organization of the United Nations and the USDA.
Particularly in developing countries, where fertility rates are two to four times higher than those of the United States, annual food production would have to increase between 2.7 percent and 3.9 percent.
If population growth and food production are not altered in these countries basic needs will continue to be unmet.
As We Go To PRESS
The safety of the American food supply took center stage in August 1997. Hudson Foods, one of the country’s largest suppliers of ground beef patties, recalled and then destroyed 25 million pounds of ground beef processed at its Columbus, Nebraska, plant.
The recall was prompted when eighteen people became ill after eating hamburgers made with meat contaminated by a potentially deadly strain of the E.
Coli bacterium. No deaths have occurred, but additional cases of illness have been reported among a group of Florida Scouts who ate Hudson Foods beef patties purchased at a local Sam’s Club.
Hudson Foods disputed accusations that its production process was to blame for bacterial contamination. The company claims that the meat was contaminated at the slaughterhouse before it arrived at the Hudson plant. nevertheless,
Burger King decided to drop Hudson Foods as its supplier of ground beef patties, and Wal-Mart and Sam’s Club are considering such a move. The Columbus plant has been sold to a competitor and will re-open under its new ownership.
Because our food supply is so quickly and widely distributed around the country, the need for a federal inspection system is clear.
The FDA and other regulatory agencies promptly traced the source of the E. coli contamination and urged a recall; it is doubtful that an industry-based inspection system would have acted as swiftly.
- Carbohydrates, fats, and protein supply the body with calories.
- The molecular complexity of carbohydrates differs, with sugars being the least complex and starches the most complex.
- Fat plays an important role in nutritional health beyond serving as the body’s primary site for the storage of excess calories.
- Dietary fats can be classified on the basis of the number of double bonds within their molecular makeup. Alteration of fat’s chemical bonding through hydrogenation may result in the formation of potentially harmful trans-fatty acids.
- Concern over tropical oils and omega-3 fatty acids reflects specific aspects of the role of dietary fats in sound nutrition.
- Cholesterol-free and low-fat foods play important roles in today’s dietary practices.
- Fat-free foods made with Olestra (Olean) contain considerably fewer calories than their fat-containing counterparts, but they may be poorly tolerated by some people.
- Protein supplies the body with amino acids that subsequently provide the material needed by the body to construct its own protein.
- The protein of plant origin is an incomplete protein in that any single source lacks one or more of the essential amino acids. Protein from animal sources is a complete protein; however, it contributes to higher levels of saturated fat in the diet.
- Vitamin serves as catalysts for the body and is found in either water-soluble or fat-soluble forms.
- Minerals are incorporated into various tissues of the body and also participate in regulatory functions within the body.
- Adequate water and fluids are required by the body on a daily basis and are obtained from a variety of food sources, including beverages.
- Fiber is an indigestible plant material and can be found in two forms, water-soluble and water-insoluble. Soluble fiber contributes to the removal of cholesterol from the blood, while insoluble fiber contributes to stool formation.
- Most nutrients are absorbed in the first 18 inches of the small intestine, at which point they enter into the venous blood drainage for eventual distribution throughout the body.
- Six food groups are currently identified, although only five been assigned a recommendation regarding the number of daily servings. Each food group supplies specific nutrients to the diet.
- To follow a food group-based dietary plan, people must be able to classify each food, know the number of recommended servings from each food group, and recognize the amount of food that constitutes a single serving.
- For a well-balanced diet, a variety of foods from each group must be eaten, rather than relying on a single food or a few favorites.
- Fast foods should play a limited role in daily food intake because of their high fat density, as well as their high levels of sugar and sodium.
- Phytochemicals are food-based chemical compounds thought to give the body some protection against harmful chemical reactions, such as the formation of free radicals, that may play a role in cancer and cardiovascular disease.
- Food additives enhance the overall quality of our food supply and the convenience of its use.
- New food labels provide considerably more information for the consumer than did labels used previously.
- The Dietary Guidelines for Americans focus on the role of fat, saturated fat, sugar, starch, sodium, alcohol, and weight management in health and disease.
- Additional dietary recommendations can be made for specific groups of people, such as increased calcium and red meat consumption for younger adult women.
- Ovolactovegetarian, lactovegetarian, vegan vegetarian, and semivegetarian diets represent a different form of vegetarianism.
- Older adults must consider the nutrient density of a particular food item because they need adequate levels of nutrients but require relatively fewer calories than young adults.
- A variety of factors contribute to malnourishment in many areas of the world.
- Improved food technology may not make it possible to feed the world’s population in the absence of greater efforts to control population growth.
Meals without Meat: Following a Semi vegetarian Diet
People become vegetarians for many reasons. Some shun meat and animal products for ethical reasons. Others choose vegetarianism for health reasons. Often it seems that vegetarians are placed in opposition to those who eat meat and that the two lifestyles are incompatible. In recent years, however, some people have found a middle ground between the two eating styles.
These so-called semivegetarians are increasing their intake of vegetables and cutting back greatly on meat consumption but not necessarily eliminating meat entirely.
According to a recent National Restaurant Association poll, one in five people chooses to eat at restaurants that offer at least a few meatless entrees1.
There are several types of vegetarians. Vegans are the most restrictive with their diets, eating only fruits, grains, and vegetables2. Lactovegetarians consume milk products along with fruits, vegetables, and grains, and ovolactovegetarians include both eggs and milk products in their diets.
Semivegetarians add occasional servings of fish and poultry to the ovolactovegetarian diet, and some even eat red meat on occasion 3,4.
Benefits of vegetarianism
Semivegetarianism is the most popular option among the 12 million Americans who consider themselves to be vegetarians, 4 one-third of whom say they still sometimes eat chicken or fish. (See details eat fish bones)
Others even eat a little red meat now and then1. Whereas most vegetarians seem to embrace this lifestyle for health reasons4, some people become vegetarians for ethical reasons.
These people cite the inhumane conditions in which factory farm animals are raised and processed as reasons to boycott the eating of animal products5.
The convictions of these people suggest that they are more likely to be vegans, lactovegetarians, or ovolactovegetarians than semivegetarians.
The health benefits of vegetarianism are many. Six of the ten leading causes of death in the United States are linked to red meat consumption6.
Cutting meat consumption can decrease the risk of heart attacks4, gallstones, high blood pressure, diabetes, and stroke1, and eating more vegetables in place of meat may decrease the risk of some types of cancer2,7.
In addition, animals raised in factory farms are often given antibiotics to keep them healthy until they get to market; however, constant exposure to antibiotics may cause some bacteria to become resistant, and these bacteria may, therefore, be present in meat at the store8. A vegetarian diet can also aid in weight loss and prevention of obesity2.
Some risks are associated with following a purely vegetarian diet, however. Protein in plants is generally of lower quality than protein found in animal products, so those on a vegetarian diet must be careful to eat a variety of plant foods to get all of the essential amino acids.
Eliminating meat altogether may also lead to a deficiency of vitamin B12, which can cause brain and nerve damage2. Eating foods fortified with this vitamin, such as cereals, bread, and fruit juice1, or taking the vitamin, such supplements can ward off B12 deficiency.
Vitamin D, which is needed for bone and tooth development, maybe lacking in vegetarian diets2. Vegans must make sure they get enough vitamin D by eating fortified foods or getting enough sunlight exposure to promote vitamin D production in the body.
Vegetarians should eat plant foods high in iron, such as apricots, bran flakes, spinach, and turnip greens to prevent iron deficiency.
Coupled with this, eating fruits and vegetables high in vitamin C helps the body to absorb more of the iron in the diet1. Calcium supplements may also be necessary, since vegan diets may make calcium difficult to absorb2.
Vegetarian foods are often delicious as well as healthful.
Is Semivegetariansm Really Vegetarian?
There is some controversy over whether the semivegetarian diet truly qualifies as “vegetarian”. Many people on a strict vegetarian diet do not consider the semivegetarian diet to be vegetarian. To them, and consumption of meat products is considered a compromise to vegetarian principles5.
Likewise, there are debates over the appropriate use of dairy products and eggs among the various vegetarian groups. Some semivegetarians even acknowledge that they are not “real” vegetarians9.
The use of the term semivegetarian may not be acceptable to some vegetarians, but there is little doubt that the semivegetarian diet is much healthier than the typical meat-laden Western diet. Semi-. almost, not quite vegetarianism may be the smartest choice of all.
A recent study revealed that “meat avoiders” had the lowest levels of fat intake per day (54g) compared with both meat eaters (67g) and vegetarians (61g).
This study concluded that when meat was totally eliminated from the diet, higher amounts of cheese and vegetable oils overcompensated for it1. Interest in the semivegetarian diet came about as a result of recommendations from several groups in the 1980s.
The American Cancer Society, the American Heart Association, and the National Academy of Science all recommended dietary changes that were closely related to the typical semi-vegetarian diet8. The health benefits of such a diet are well documented.
The debate over whether semivegetarians should be categorized as vegetarians seem to revolve around ethical questions concerning the treatment of animals that must be exploited to obtain this foods5. They are thus morally opposed to semi vegetarianism.
Cutting back, however, may at least cause a decrease in demand for meat and animal products, and some semivegetarians may not effectively address the ethical questions raised by animal rights activists, it has become an acceptable way of eating for many people who are looking for a way to eat more healthfully.
Becoming Semi vegetarian
The semivegetarian diet may be desirable to some people because the limited consumption of meat products may help ward off some nutrient deficiencies4, and such a diet can be healthier than that of the typical American.
However, a person who wishes to adopt the semivegetarian diet should not make the change overnight3. The sudden elimination of most meat and other animal products can be too drastic of a change to adhere to, so it is best to cut back on them gradually.
Such a change should also be discussed first with a doctor since dietary alterations can cause difficulty for people who are pregnant, nursing, or have health problems4.
A gradual cutback in meat consumption can be accomplished by keeping track of how much meat you consume per day. Reduce meat consumption slowly until you have tapered off to about four ounces a day.
Meat can be used as a condiment (such as chicken strips on a salad) instead of as a main course, and fish can be substituted for red meat10.
Try new vegetarian foods at each meal, and keep track of your likes and dislikes. Adding more fruit to your meals can increase the variety of your diet as well3.
Using a vegetarian food pyramid can help non-meat eaters and semivegetarians to follow a healthful diet (see Figure 5-7).
This pyramid is similar to the USDA Food Guide Pyramid (see Figure 5-3), but it replaces the meat, poultry, fish, dry beans, eggs, and nuts group with eggs, legumes, nuts, and seeds group. (In 1996 the USDA confirmed that a vegetarian diet can fulfill the nutrient needs of Americans1) Lactovegetarians can omit eggs from this group.
The pyramid advises vegetarians of all types to eat six to eleven servings of bread, cereal, rice, and pasta; three to five servings of vegetables; two to four servings of fruit; and two to three servings of milk, yogurt, or cheese per day.
Legumes can be used as a substitute for meats for obtaining iron, calcium, protein, and zinc, but keep in mind that vitamin B12 is not found in plant foods10. Semivegetarians can obtain some B12 from the limited meats they consume but should be careful not to decrease B12 intake too much.
Also, the occasional fast-food meal is not forbidden. Fast food can provide a change of pace, and many healthy fast-food meals are available.
Children can also be involved in the change of diet (but consult your pediatrician first to be safe). Making dietary changes a family affair can make the adjustment easier. Getting kids involved in meal planning, cooking, and label reading can make things more interesting for them6.
Dietary changes can be a difficult adjustment for kids, however, so don’t hold them to the same restrictions as the adults3. This may help parents and children avoid arguments over meals and can make meals more enjoyable for the kids.
A semivegetarian diet may be an acceptable alternative for people who want to cut back significantly on meat consumption but who do not want to give up meat altogether.
Reducing the amount of meat in the diet can have definite health benefits, while not eliminating meat can allow for variety in your diet and flexibility in social situations, such as banquets and receptions at which few or no meatless items are served1. Check with your doctor to see if such a diet could have advantages for you. Bon appetit!
For Discussion . . . . .
Is semi vegetarianism more ethically sound than the typical Western diet, or is there no difference between eating meat occasionally and eating it often? Should semivegetarians be considered for you in the food choices you make? Is health concern for you in your diet?