Vegetarian Diets : Precautions

by Food and Drug Administration (FDA)

(Page 2 of 2)

The American Dietetic Association's position paper on vegetarian diets states, "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." Dwyer and Suzanne Havala, also a registered dietitian, updated the paper in the 1993 issue of the association's journal.

It's generally agreed that to avoid intestinal discomfort from increased bulk, a person shouldn't switch to foods with large amounts of fiber all at once. A sensible approach is to slowly increase consumption of grains, legumes, seeds, and nuts. "Some may choose to eliminate red meat but continue to eat fish and poultry occasionally, and such a diet is also to be encouraged," Jack Zeev Yetiv, M.D., Ph.D., in his book Popular Nutritional Practices: A Scientific Appraisal.

As with any diet, it's important for the vegetarian diet to include many different foods, since no one food contains all the nutrients required for good health. "The wider the variety, the greater the chance of getting the nutrients you need," says FDA's Vanderveen.

In its position paper on vegetarian diets, the American Dietetic Association states that, with a plant-based daily diet, eating a variety of foods and sufficient calories for energy needs will help ensure adequate intakes of calcium, iron and zinc.

The mixture of proteins from grains, legumes, seeds, nuts, and vegetables provides a complement of amino acids so that deficits in one food are made up by another. Not all types of plant foods need to be eaten at the same meal, since the amino acids are combined in the body's protein pool.

"Soy protein," the paper states, "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."

The Institute of Food Technologists also recommends careful diet planning for vegetarians. This is especially important when the diet excludes dairy foods, to ensure adequate intake of calcium, iron, riboflavin, and vitamin D. For these vegetarians, the institute recommends calcium supplements during pregnancy, when breast-feeding, and for infants and children.

The institute and the American Dietetic Association say a vitamin D supplement may be needed if sunlight exposure is limited. (Sunlight activates a substance in the skin and converts it into vitamin D.)

They also point out that vegan diets should include a reliable source of vitamin B12, because this nutrient occurs only in animal foods. Vitamin B12 deficiency can result in irreversible nerve deterioration.

The need for vitamin B12 increases during pregnancy, breast-feeding, and periods of growth, Dwyer says. In a recent issue of Annual Review of Public Health, she writes that elderly people also should be especially cautious about adopting vegetarian diets because their bodies may absorb vitamin B12 poorly.

Unless advised otherwise by a doctor, those taking dietary supplements should limit the dose to 100 percent of the U.S. Recommended Daily Allowances.

With the array of fruits, vegetables, grains, and spices available in U.S. grocery stores and the availability of vegetarian cookbooks, it's easy to devise tasty vegetarian dishes that even non-vegetarians can enjoy.

However, the key to any healthful diet — vegetarian or non-vegetarian — is adherence to sound nutrition principles.

Replacing Animal Sources of Nutrients

Vegetarians who eat no animal products need to be more aware of nutrient sources. Nutrients most likely to be lacking and some non-animal sources are:

• vitamin B12 — fortified soy beverages and cereals
• vitamin D — fortified soy beverages and sunshine
• calcium — tofu processed with calcium, broccoli, seeds, nuts, kale, bok choy, legumes (peas and beans), greens, lime-processed tortillas, and soy beverages, grain products, and orange juice enriched with calcium
• iron — legumes, tofu, green leafy vegetables, dried fruit, whole grains, and iron-fortified cereals and breads, especially whole-wheat. (Absorption is improved by vitamin C, found in citrus fruits and juices, tomatoes, strawberries, broccoli, peppers, dark-green leafy vegetables, and potatoes with skins.)
• zinc — whole grains (especially the germ and bran), whole-wheat bread, legumes, nuts, and tofu
• protein — tofu and other soy-based products, legumes, seeds, nuts, grains, and vegetables

American Dietetic Association Recommendations

For people who follow vegetarian diets, the American Dietetic Association has these recommendations:

• Consult a registered dietitian or other qualified nutrition professional, especially during periods of growth, breast-feeding, pregnancy, or recovery from illness.
• Minimize intake of less nutritious foods such as sweets and fatty foods.
• Choose whole or unrefined grain products instead of refined products.
• Choose a variety of nuts, seeds, legumes, fruits, and vegetables, including good sources of vitamin C to improve iron absorption.
• Choose low-fat or nonfat varieties of dairy products, if they are included in the diet.
• Avoid excessive cholesterol intake by limiting eggs, if they are included in the diet, to three or four egg yolks per week.
• For infants, children and teenagers, ensure adequate intakes of calories, vitamin D, calcium, iron, and zinc. (Intakes of vitamin D, calcium, iron, and zinc are usually adequate when a variety of foods and sufficient calories are consumed.)
• If exclusively breast-feeding premature infants or babies beyond 4 to 6 months of age, give vitamin D and iron supplements to the child from birth or at least by 4 to 6 months, as your doctor suggests.
• Usually, take iron and folate (folic acid) supplements during pregnancy.
• In addition, for vegans:
• Use properly fortified food sources of vitamin B12, such as fortified soy beverages or cereals, or take a supplement.
• If sunlight is inadequate, take a vitamin D supplement during pregnancy or while breast-feeding.

About the Author

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