ADA POSITION
PAPER ON VEGETARIANISM
By American Dietic Assosiation
Position of the American Dietic Association:
Vegetarian Diets A considerable body of scienticic data suggests positive relationships
between vegetarian diets and risk reduction for several chronic degenerative
diseases and conditions, including obesity, coronary artery disease, hypertension,
diabetes mellitus, and some types of cancer.
Position Statement
It is the position of The American
Dietic Association that vegetarian diets are healthful and nutritionally adequate
when appropriately planned.
Vegetarianism in Perspective
There is no single vegetarian eating
pattern. The vegetarian diet is mainly plant foods: fruits, vegetables, legumes,
grains, seeds and nuts. Eggs, dairy products, or both may be included as well.
The lactovegetarian diet is fruits, vegetables, grains, dairy foods, and their
products whereas the lacto-ovovegetarian diet also adds eggs. The vegan, or
total vegetarian, diet completely excludes meat, fish, fowl, eggs, and diary
products. Even within specific classifications of the diet, considerable variation
may exist in the extent to which animal products are avoided. Therefore, individual
assessment is required in order to accurately evaluate the nutritional quality
of a given diet.
Studies of vegetarians indicate that
they often have lower mortality rates from several chronic degenerative diseases
than do nonvegetarians. These effects may be atttributable to diet as well as
to other lifestyle characteristics such as maintaining desirable weight, regular
physical activity, and abstainence from seeking, alcohol, and illicit drugs.
In addition to possible health advantages,
other considerations that may lead to the adoption of a vegetarian diet include
environmental or ecological concerns, world hunger issues, economic reasons,
philosophical or ethical reasons, and religious beliefs.
Implications for Health Promotion
Mortality from coronary artery disease
is lower in vegetarians than in nonvegetarians. Total serum cholesterol and
low-density lipoprotein cholesterol levels are usually lower, whereas high density
lipoprotein cholesterol and triglyceride levels vary, depending on the type
of vegetarian diet followed. Low-fat, low cholesterol vegetarian diets may decrease
levels of apoprotein A, B, and E; alter platelet composition and platelet function;
and decrease plasma viscosity. One study demonstrated reversal of even severe
coronary artery disease without the use of lipid lowering drugs by using a combination
of a vegetarian diet deriving less than 10% of its energy from fat, smoking
cessation, stress management, and moderate exercise. Vegetarians have lower
rates of hypertension and non-insulin-dependent diabetes mellitus than do nonvegetarians;
lessening these risk factors may also decrease the risk of cardiovascular and
coronary artery disease in the vegetarian population.
Seventh-day Adventist vegetarians
have lower rates of mortality from colon cancer than the general population.
This may be attributable to dietary differences that include increased fiber
intake; decreased intake of total fat, saturated fat, cholesterol, and caffeine;
increase intake of fruits and vegetables; and, in lactovegetarians, increased
intakes of calcium. The dietary differences, especially in vegans, may produce
physiologic changes that may inhibit the casual chain for colon cancer. Reduced
consumption of meat and animal protein has also been associated with decreased
colon cancer in some, but not all, studies of omnivores. Lung cancer rates are
lower in vegetarians, chiefly because they usually do not smoke, but possibly
also because of diet. Research suggests that vegetarians are also at decreased
risk for breast cancer.
Obestiy, a major public health problem
in the United States, exacerbates or complicates many disease. Vegetarians,
especially vegans, often have weights that are closer to desirable weights than
do nonvegetarians.
Vegetarians may be at lower risk for
non-insulin-dependent diabetes because they are leaner than nonvegetarians.
Also, vegetarians' high intake of complex carbohydrates, which are often relatively
high in fiber content, improves carbohydrate metabolism and may lower basal
blood glucose levels.
Nutrition Considerations
Plant sources of protein alone can
provide adequate amounts of the essential and nonessential amino adds, assuming
that dietary protein sources from plants are reasonably varied and that caloric
intake is sufficient to meet energy needs. Whole grains, legumes, vegetables,
seeds, and nuts all contain essential and nonessential amino adds. Conscious
combining of these foods within a given meal, as the complementary protein dictum
suggests, is unnecessary. Additionally, soy protein has been shown to be nutritionally
equivalent in protein value to proteins of animal origin and, thus, can serve
as the sole source of protein intake if desired.
Although most vegetarian diets meet
or exceed the Recommended Dietary Allowances for protein, they often provide
less protein than nonvegetarian diets. This lower protein intake may be associated
with better calcium retention in vegetarians and improved kidney function in
individuals with prior kidney damage. Further, lower protein intakes may result
in a lower fat intake with its inherent advantages, because foods high in protein
are frequently high in fat also.
Suggested
Food group daily servings Serving sizes
---------- -------------- -------------
Breads, cereals, 6 or more 1 slice bread
rice, and pasta 1/2 bun, bagel, or English muffin
1/2 cup cooked cereal, rice, or
pasta
1 oz dry cereal
Vegetables 4 or more 1/2 cup cooked or 1 cup raw
Legumes and other 2 to 3 1/2 cup cooked beans
meat substitutes 4 oz tofu or tempeh
8 oz soy milk
2 Tbsp nuts or seeds (these tend to
be high in fat, so use sparingly
if you are following a low-fat
diet)
Fruits 3 or more 1 piece fresh fruit
3/4 cup fruit juice
1/2 cup canned or cooked fruit
Fats, sweets, Go easy on Oil, margarine, and mayonnaise
these foods Cakes, cookies, pies, pastries,
and candies
Daily food guide for vegetarians.
Daily food guide for vegetarians.
Source: Eating Well--The Vegetarian Way. Chicago, IL: American Dietetic Association;
1992.
Plant carbohydrates are usually accompanied
by liberal amounts of dietary fiber. This is in contrast to animal products,
which are devoid of fiber. Fiber has been shown to be important in the prevention
and treatment of certain conditions and diseases.
Vegetarian diets that are low in animal
products are typically lower than nonvegetarian diets in total fat, saturated
fat, and cholesterol, factors associated with reduced risk of coronary artery
disease and some forms of cancer.
Adequate iron nutriture depends on
both the amount of dietary iron consumed and the amount absorbed. Inhibitors
and enhancers affect the absorption of nonheme iron, the form of iron found
in plants. However, inhibitors and enhancers can offset each other when a variety
of foods is consumed. Vegetarians are not at greater risk of iron deficiency
than nonvegetarians, but western vegetarians generally have greater iron status
than those in developing countries. Western vegetarians generally have an adequate
intake of iron from plant products. They also consume greater amounts of ascorbic
acid, an important enhancer of nonheme iron absorption. In contrast, vegetarians
in developing countries rely on food staples that are low in iron; consume less
ascorbic acid.
The Recommended Dietary Allowance
for vitamin B-12 is minute. Vitamin B-12 is produced by microorganisms present
in the guts or gastrintestinal tracts of animals and human beings, as well as
in dirt on the surface of unwashed plants. Vitamin B-12 is found in all animal
products, hence, a pattern that includes animal products such as milk and milk
products is unlikely to be deficient in vitamin B-12. Bacteria produce vitamin
B-12 in the human gut, but it appears to be produced beyond the ileum, the site
of vitamin B-12 absorption in the intestine .
Lack of intrinsic factor in the stomach,
rather than diet, however, is the most common cause of vitamin B-12 deficiency.
Atrophic gastritis, with the consequent bacterial overgrowth of the upper gut,
may also contribute to vitamin B-12 deficiency, especially in the elderly. Plants
provide no vitamin B-12. In countries where sanitation is poor, vegans may derive
vitamin B-12 from foods that are contamninated with microbes and organisms that
produce the vitamin, such as on the surfaces of unwashed fruits or vegetables.
In Western countries, however, where sanitary practices are better, the risk
of vitamin B-12 deficiency for vegans may be greater.
Vegans should include a reliable source
of the vitamin in their diets. Spirulina, seaweed, tempeh, and other fermented
foods are NOT reliable sources of vitamin B-12. As much as 80% to 94% of the
so-called vitamin B-12 in these foods, as measured by microbiological assay,
may be inactive analogs. Cyanocobalamin, the form of vitamin B-12 that is physiologically
active for human beings, is available from vitamin supplements or fortified
foods such as some commercial breakfast cereals, soy beverages, some brands
of nutritional yeast, and other products.
Certain plant constituents appear
to inhibit the absorption of dietary calcium, but within the context of the
total diet, this effect does not appear to be significant. Calcium from low-oxalate
vegetable greens, such as kale, has been shown to be absorbed as well or better
than calcium from cow's milk. Calcium deficiency in vegetarians is rare, and
there is little evidence to show that calcium intakes below the Recommended
Dietary Allowance cause major health problems in the vegetarian population.
The relatively high US recommendations for calcium intake, compared with those
for populations consuming a more plant based diet, are designed to compensate
for the calciuric effect of high intakes of animal protein which are customary
in the United States. Studies have shown that vegetarians, on the other hand,
absorb and retain more calcium from foods than do nonvegetarians.
Zinc is necessary for proper growth
and development. Good plant sources include grains, nuts and legumes. Western
vegetarians usually have satisfactory zinc status.
Groups with Special Needs
Infants, children, and adolescents
who consume well-planned vegetarian diets can generally meet all of their nutritional
requirements for growth. Those who follow vegan or veganlike diets should consume
a reliable source of vitamin B-12 and should have a relaible source of vitamin
D. Calcium, iron, and zinc intakes may also deserve special attention, although
intakes are usually adequate when reasonable variety and adequate energy are
consumed.
If exposure to sunlight is limited,
the need for vitamin D supplementation should be assessed. Because vegan diets
tend to be high in bulk, care should be taken to ensure that caloric intakes
are sufficient to meet energy needs, particularly in infancy and during weaning.
Both vegetarians and nonvegetarians whose infancts are premature or solely breastfed
beyond 4 to 6 months of age should provide supplements of vitamin D, if exposure
to sunlight is inadequate, and iron from birth or at least by 4 to 6 months
of age.
Well-planned vegetarian diets can
be adequate for pregnant and lactating women. Vegetarians and nonvegetarians
alike are generally advised to take iron and folic acid supplements during pregnancy
although vegetarians frequently have greater intakes of those nutrients than
do nonvegetarians. A regular source of vitamin B-12 is recommended for vegans
during pregnancy and lactation. A vitamin D supplement should be taken by pregnant
and lactating vegans if exposure to sunlight is inadequate. Consumption of a
variety of foods and adequate energy will help ensure adequate intakes of calcium,
iron, and zinc.
Meal Planning
In planning vegetarian diets of any
type, one should choose a wide variety of foods and ensure that the caloric
intake is adequate to meet energy needs. ( Additionally, the following recommendations
are in order.
.Keep the intake of low nutrient-dense
foods, such as sweet and fatty foods, to a minimum. -Choose whole or unrefined
grain products, instead of refined products, whenever possible, or use fortified
or enriched ceral products.
.Use a variety of fruits and vegetables,
including a good food source of vitamin C.
.If milk or dariy products are consumed,
use low-fat or nonfat varieties.
.Limit egg intake to 3 or 4 yolks
per week.
Vegans should have a relaible source
of vitamin B-12, such as some fortified commercial breakfast cereals, fortified
soy beverages, or a cyancobalamin supplement. A vitamin D supplement may be
indicated if exposure to sunlight is limited.
Vegetarian and nonvegetarian infants
who are soley breastfed beyond 4 to 6 months of age should receive supplements
of iron and vitamin D if exposure to sunlight is limited.
The Dietary Guidelines for Americans
recommend a reduction in fat intake and an increased consumption of frutis,
vegetables, and whole grains. Well-planned vegetarian diets can effectively
meet these guidelines and can be a health-supporting dietary alternative.