Dietary Guidelines

Dietary guidelines are designed to provide advice for healthy individuals regarding diet and related life-style practices to promote healthful eating and reduce the risk of disease.1 Dietary guidelines differ from nutrient standards such as the Reference Dietary Intakes (RDI) and Recommended Dietary Allowances (RDA),2 or food guides such as the Food Guide Pyramid.3,4 Nutrient standards define the reference points for average daily intake of essential nutrients; food guides provide a framework for selecting kinds and amounts of foods of different types that together provide a nutritionally adequate diet and dietary guidelines give advice on consumption of types of food or food component related to a public health concern. The guidelines are intended to be population-based recommendations for health promotion and disease prevention.

A. Overview 1. U.S. Guidelines

The dietary guidelines concept was first introduced by Atwater over a century ago. He indicated that food production at the time provided a relative excess of fats, meats, starch, and sugar, and recommended a diet that provided 33% of energy as fat and 15% as protein.5 In the more recent history of dietary guidelines, a major step was achieved in 1977 when the U.S. Congress issued the landmark Dietary Goals for the United States after extensive hearings held by the Senate Select Committee on Nutrition and

Human Needs.6 The decades after World War II were marked by a progression of thinking among nutrition scientists and policymakers from problems of hunger and nutrient adequacy to the role of diet as a controllable risk factor in chronic degenerative conditions such as heart disease, stroke, diabetes, and cancer that are the leading causes of death in the U.S.7 The dietary goals report attributed these killer diseases to dietary and other life-style factors and established quantitative standards for what was considered to be a more optimum intake of total fat, saturated fatty acids, total carbohydrate, added sugars, cholesterol, sodium, and protein. The report generated much controversy among nutritionists and scientists about the proposed standards and goals.

First released in 1980, the Nutrition and Your Health: Dietary Guidelines for Americans booklet represented a joint effort by the Departments of Agriculture and Health and Human Services to promote the dietary recommendations addressed in the "goals" for which there was considerable consensus and which were deemed to have greatest potential benefit for public health.8 The dietary guidelines were revised and reissued in 1985, 1990, and 1995. Most recently, in the year 2000, the fifth revision of the guidelines was released.1 Meanwhile, there have been numerous scientific papers and research reviews that have provided the documentation and underlying scientific research needed to validate the guidelines. Most prominent, from the national perspective, were (1) The Surgeon General's Report on Nutrition and Health (1988) published by the Surgeon General's office,9 and (2) the Diet and Health: Implications for Reducing Chronic Disease Risk (1989) document published by the National Academy of Sciences (NAS).10 Table 15.1 compares the year 2000 Dietary Guidelines for Americans with the Diet and Health recommendations. The Dietary Guidelines substantially reflect the NAS Diet and Health recommendations and translate them into consumer-friendly language. Although the Dietary Guidelines statements are simple, concise and descriptive, much of the quantitative aspects of the Diet and Health recommendations are maintained in the more detailed instructions given in the guidelines booklet and in the Food Guide Pyramid advice.

Political legitimacy was achieved by the passage of the National Nutrition Monitoring and Related Research Act of 1990 (PL101-445), which established the guidelines as statements of federal nutrition policy and required the secretaries of Agriculture and Health to reevaluate and update (if needed) the guidelines every 5 years.5 As official U.S. policy, they form the basis for all federal nutrition feeding programs and dietary guidance for the public. To encourage greater implementation, they are incorporated in the health promotion objectives of the Health Objectives for the Nation document.11

2. International Guidelines

The U.S. is not alone in issuing dietary guidelines. Most of the industrialized countries in the world, including Australia, Canada, Denmark, Ireland, Finland, France, Germany, Hungary, India, Israel, Italy, Japan, South Korea, Netherlands, New Zealand, Norway, Singapore, Sweden and the U.K., have their own sets of dietary guidelines. International organizations such as the World Health Organization (WHO) and the Food and Agriculture Organization, have also issued dietary guidelines. Comparisons among dietary guidelines from various countries have been published.12,13 There is considerable consistency among the guidelines from many countries as well as those issued by study groups of the WHO and the U.S. Dietary Guidelines, especially with regard to recommendations pertaining to fat, saturated fat, carbohydrate, and fiber intake.12

B. Is the Vegetarian Diet Consistent with the Dietary Guidelines? 1. What Do Vegetarians Eat?

The vegetarian label encompasses a wide variety of dietary and life-style values and practices. For the purposes of this chapter, the term vegetarian refers to a diet that avoids flesh foods such as meat, poultry, and fish but may include dairy products or eggs. The term vegan applies to a diet composed entirely of plant foods. Vegetarian and vegan diets emphasize plant foods such as grains, legumes, nuts, vegetables, and fruits. Plant-rich diets are those that include a generous proportion of plant foods and relatively small amounts of animal foods, whether meat, poultry, seafood, eggs, or dairy products. Plant-rich diets such as those consumed by traditional populations in Mediterranean countries or the Far East are sometimes referred to as vegetarian-like diets.

It is difficult to establish an exact vegetarian pattern of intake. First, individuals and groups who adopt the vegetarian diet differ in their food intake and avoidance patterns. Second, there are no large-scale dietary studies with appropriate sampling and stratification techniques conducted on vegetarians. Recently, however, Messina and Messina14 summarized the data obtained from more than 60 dietary studies conducted on vegetarians since the early 1950s. The studies reviewed encompassed various types of vegetarian eating styles, national as well as a number of international vegetarian groups, and included studies of individuals in different life-cycle stages such as childhood, adolescence, pregnancy, lactation and the elderly. The results consistently showed that vegetarians consumed less fat, saturated fat, and cholesterol and more polyunsaturated fat and dietary fiber than non-vegetarians in those studies.

Table 15.1 The Year 2000 Dietary Guidelines for Americans and the Diet and Health Recommendations

U.S. Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans, 5th edition, 20001

Committee on Diet and Health, Food and Nutrition Board, National Research Council: Diet and Health 198910

Aim For Fitness • Aim for a healthy weight.

Healthy

BMI 18.5 to 25

weight:

Overweight:

BMI 25-30

Obese:

BMI 30 and

above

Be physically active each day.

Adults:

30 minutes of

moderate

activity most

days

Children and

60 minutes of

teens:

moderate

activity most

days

Build A Healthy Base Let the Pyramid guide your food choices. Choose a variety of grains daily, especially whole grains. Choose a variety of fruits and vegetables daily. Keep food safe to eat.

Body weight

Maintain appropriate body weight. Balance food intake and physical activity.

Fat intake

Total fat 30% of calories or less

Saturated fatty acids 10% of calories

Polyunsaturated fatty acids 7% to 10% of calories

Dietary cholesterol less than 300 mg daily

Concentrated fish oils not recommended

Food groups

5 or more servings of vegetables and fruits each day, especially green and yellow vegetables and citrus fruits

Increase intake of starches and complex carbohydrates as breads, cereals and legumes. Increase of added sugars is not recommended

Protein intake

Moderate, less than twice the RDA

Alcohol consumption not recommended

For those who do drink, limit consumption to two standard drinks a day. Pregnant women and women attempting to conceive should avoid alcoholic beverages.

Table 15.1 The Year 2000 Dietary Guidelines for Americans and the Diet and Health Recommendations (Continued)

U.S. Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans, 5th edition, 20001

•Choose Sensibly

Choose a diet that is low in saturated fat and cholesterol and moderate in total fat. Choose beverages and foods to moderate your intake of sugars. Choose and prepare foods with less salt If you drink alcoholic beverages, do so in moderation.

•Food Guide Pyramid

Bread, Cereal, Rice, Pasta Group (Grains Group): 6-11 servings per day

(especially whole grain) Vegetable Group: 3-5 servings per day Fruit Group: 2-4 servings per day Milk, Yogurt, Cheese Group

(Milk Group): 2-3 servings per day (preferably fat-free or low-fat)

Committee on Diet and Health, Food and Nutrition Board, National Research Council: Diet and Health 198910

• 6 grams sodium chloride (NaCl)

per day or less

• Adequate calcium intake

• Dietary supplement intake

Avoid taking in excess of the RDA. Adequate fluoride intake

Not only does the macronutrient composition of vegetarian diets differ from those of non-vegetarians, but so too does the pattern of food group consumption. In vegetarian households, children and adults consume substantially more vegetables, fruits, legumes, and nuts than non-vegetar-ians.15-17 Vegetarian Seventh-Day Adventists eat more whole grains, fruits, tomatoes, legumes, nuts, and plant-based meat substitutes than their non-vegetarian counterparts.18

Observations gleaned from descriptive studies of various vegetarian groups allow some generalizations about the diet.14-18 Table 15.2 offers a qualitative description of the nutritional and food group patterns of

Table 15.2 Vegan, Vegetarian and Mediterranean Dietary Patterns compared to the Dietary Guideline Recommendations14-18

Dietary Guidelines

Vegan

Vegetarian Mediterranean

Total fat < 30% energy Saturated fatty acids < 10%

energy Monounsaturated fatty acids < 10% energy Polyunsaturated fatty acids < 10% energy Dietary cholesterol < 300 mg per day

Protein (animal sources) Protein (vegetable sources) Fiber ~ 25 g per day Whole grain breads and cereals: 6-11 servings per day

Fruits and vegetables: 5-9 servings per day Meat, poultry, fish, dry beans, eggs, nuts group: 5-7 ounces per day Meat, poultry, fish Eggs

Dry beans Nuts

Milk, yogurt, cheese: 2-3 servings per day

ft ft ft

ft ft

ft ft ft

ft ft o

ft ft ft U

ft higher intake, ^ similar intake, ft lower intake, 0 avoided vegetarian and plant-rich diets as compared with the recommendations of the Dietary Guidelines ft

2. Vegetarian Diets, Plant Foods, and the Guidelines

Modern-day vegetarians have, for more than 100 years now, advocated plant foods as being healthier. Meanwhile, scientific views on the relative proportions of plant and animal foods in healthful diets have markedly shifted since the introduction of the dietary guidelines. Food guides, nutrient standards, and dietary advice prior to the guidelines emphasized foods from animal sources (meat and dairy products) to prevent deficient intake of essential nutrients. The guidelines instruct the public to eat less energy, fat, saturated fat, cholesterol, etc. and more complex carbohydrates and fiber. As succinctly expressed by Marion Nestle19 the principle sources of the eat-less foods (other than sugar, salt, and alcohol) are meat and dairy products, whereas the principal sources of the eat-more items are plant foods. It is important to note that the 1995 version of the guidelines included the statement: "Vegetarian diets are consistent with the Dietary Guidelines for Americans and can meet Recommended Dietary Allowances for nutrients."20 To express this more accurately, the optimum diet as recommended by the guidelines emphasizes plant foods and substantially resembles the vegetarian diet. In fact, the dietary recommendations common among the advice promoted by various authoritative groups and countries can best be achieved by adhering to a largely vegetarian dietary pattern.

3. The Year 2000 Guidelines

The year 2000 guidelines encompass three categories designated as the ABCs for good health:

1. Aim for Fitness statements emphasize healthy weight and physical activity.

2. Build a Healthy Base statements promote the Food Guide Pyramid.

3. Choose Sensibly statements reflect the traditional guideline recommendations.1

a. Aim for Fitness

The first message of the guidelines is intended to emphasize the importance of weight control and physical activity in disease prevention. Maintenance of a healthy weight reduces the risk of heart disease, type 2 diabetes, hypertension, stroke, and certain cancers. Most plant foods are bulky and low in calories. This property of high volume and low caloric density promotes fullness and satiety and reduces the likelihood of overeating. Vegetarians emphasize whole foods, especially whole-grain cereals, which are higher in dietary fiber than the refined varieties. Studies have consistently reported that vegetarians are, on the average, thinner than non-vegetarians when the average BMI is compared. Lower BMIs mean lower prevalence of obesity among vegetarians than in comparable groups.21-23

b. Build a Healthy Base

This message is intended to establish the food guide pyramid as the basis for food selection, to promote a variety of plant food consumption, and to address food safety issues. There is widespread consensus about the guideline to eat more and varied plant foods. Fruits, vegetables, whole grains, and legumes are significant sources of most essential nutrients such as complex carbohydrate, protein, essential fats, vitamins, and minerals. More importantly, they are exclusive sources of fiber, folate, vitamin C, carotenoids, and other phytochemicals. Numerous epidemiological studies show plant foods to be strongly associated with the prevention of chronic disease such as heart disease and cancer.21,24-26 In the food guide pyramid, first grains, then fruits and vegetables, occupy the greatest amount of space at the base of the pyramid, sending the message that these foods are more important and should be consumed in greater quantities than foods higher up in the pyramid.

Dietary advice often includes an emphasis on consuming a variety of foods. It is more likely that a wide complement of needed nutrients will be obtained if a variety of items from each food group is selected. Recently, however, dietary variety per se has been linked to excessive consumption and increased body weight.27 The 2000 Dietary Guidelines apply variety only to the consumption of plant foods, not to the myriad refined products found on supermarket shelves.

Earlier dietary guideline statements encouraged the consumption of complex carbohydrate and fiber. Because of the ambiguity of its definition, the term complex carbohydrate does not appear in the 2000 guidelines. The intake of fiber is emphasized as well as that of whole grain breads and cereals. Vegetarian diets traditionally include whole grain cereals and whole foods instead of white flour and refined products.18

c. Choose Sensibly

The third message reiterates the advice that first prompted the dietary goals, and addresses intake of fat, saturated fat, sugar, salt, and alcohol.

Total fat: Most dietary guidelines encourage a reduction in total fat intake to help lower the amount of saturated fat in the omnivorous diet and to facilitate weight control. The NAS report Diet and Health set the target of an average of 30% or less of calories from fat. Dietary guidelines have used expressions such as "reduce fat," "limit fat," or "choose a diet low in fat" in their statements. The fifth edition of the Dietary Guidelines employs the words "moderate in fat" to counteract the common misconception that low fat means no fat. Vegetarian diets are not intrinsically low in fat and can be planned to provide a range of fat intake. However, even when higher in fat, vegetarian diets are low in saturated fat.

Saturated fat: Much experimental and epidemiological evidence implicates saturated fatty acid intake as associated with high levels of blood cholesterol and increased risk of coronary heart disease.28 High levels of blood cholesterol promote atherosclerotic lesions and thrombus formation. The Diet and Health report set the target of an average of 10% or less of calories from fat, and dietary guidelines consistently advise reductions in saturated fat intake. The greater the reduction in saturated fatty acid intake, the greater the lowering of total blood cholesterol and low density lipo-protein cholesterol (LDL). The major sources of saturated fat in the diet are foods of animal origin, such as dairy products, eggs, and meats. Diets based entirely on plant foods provide the lowest amounts of saturated fat. Vegetarian diets with moderate amounts of fat typically contain less than 10% of calories as saturated fat if low fat or non-fat dairy products are consumed, and less than 5% of calories as saturated fat if only plant foods are consumed.29

The dietary guidelines also address the intake of trans fatty acids, which may also be atherogenic. Since these are found mostly in partially hydrogenated vegetable oils, the guidelines recommend the consumption of oils and fats that have not been hydrogenated

Dietary Cholesterol. The dietary guidelines recommend a reduction in dietary cholesterol along with fat and saturated fat. Diet and Health sets a limit of 300 mg of dietary cholesterol per day. Dietary cholesterol, like saturated fat, is derived primarily from animal food sources or products made from them. Plant foods are devoid of cholesterol.

Sugar. Although sugar intake has not been directly linked to risk of disease except for dental caries, foods high in sugar and refined carbohydrates are high in calories and low in fiber and essential vitamins and minerals. Major sources of added sugar in the U.S. are beverages such as soft drinks, fruit ades, and sweetened drinks.30 Foods with added sugar tend to replace more nutrient-dense items in the diet. An emphasis on fruit consumption rather than sweetened drinks can substitute for much of the added sugar in the diet.

Salt. Dietary guidelines for the public usually include a recommendation to restrict sodium chloride intake based on the evidence, derived from epidemiological and clinical observations, for an association between dietary salt and blood pressure. Most salt is obtained from processed foods. Vegetarian and plant-rich diets based on whole or minimally refined food contain much less salt than is commonly consumed.

Gaining Weight 101

Gaining Weight 101

Find out why long exhausting workouts may do more harm than good. Most of the body-building workout and diet regimens out there are designed for the guys that gain muscle and fat easily. They focus on eating less and working out more in order to cut the excess fat from their bodies while adding needed muscle tone.

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