Nutrition Hotline
By Reed Mangels, Ph.D., R.D.
QUESTION: Is there any evidence that infants fed soy formula have an increased chance of having a soy allergy later on? B.P., VA
ANSWER: While breastfeeding is a wise choice for all infants, it is not always possible. Infant formula-either based on cow's milk or soy-is used. Cow's milk, egg, peanut, and soy account for 80 to 90 percent of the food allergies in the first few years of life. In the child with a genetic tendency to develop a food allergy, use of cow's milk or soy milk formulas and the early use of solid foods can trigger an allergic reaction. There is a reasonable chance that such an allergy would not be outgrown. In the classic form of allergy, about four out of 10 children outgrow it if the allergy occurs before age three. Food allergies which occur after age three appear to be even more persistent.
QUESTION: Are diets which are low in meat, especially beef, too low in iron and zinc for children? C.G., WA
ANSWER: Diets which contain no meat can be selected so that they contain adequate amounts of iron and zinc for children. Iron deficiency anemia is no more likely to occur in vegetarian than in non-vegetarian children. Good iron sources for vegetarian children include whole or enriched grains and grain products, iron-fortified cereals, dried beans, green leafy vegetables, blackstrap molasses, and dried fruits. Zinc intakes of lacto-ovo vegetarian and vegan children have been shown to be the same as those of nonvegetarian children and to meet recommended levels. Zinc in vegetarian diets may not be as well absorbed because of the diet's high fiber content; so vegetarians should include good sources of zinc in their diets. Zinc sources include legumes, hard cheeses, whole grain pasta, wheat germ, fortified and whole grain cereals, sea vegetables, nuts, tofu, and miso.
QUESTION: I have been a vegan for nearly 3 years and am wondering whether I need a daily source of vitamin B-12 in my diet, or whether taking a multi-vitamin supplement once a week or once every two weeks would do the trick. A.B., MD
ANSWER: Although the adult human requirement for vitamin B-12 is quite low (1 microgram a day or less), it is important for vegans to be aware of good sources of this vitamin. Vitamin B-12 deficiency leads to nerve damage, which can be irreversible and which can lead to difficulty in walking, depression, memory loss, and general weakness.
Vegans who use a vitamin B-12 supplement, either as a single supplement or in a multi-vitamin, should use it at least several times a week. Although a supplement may contain many times the recommended level of vitamin B-12, when vitamin B-12 intake is high, not as much appears to be absorbed. In order to meet your needs, you should take the vitamin several times a week. Pregnant or breastfeeding women should use vitamin B-12 on a daily basis. It is also reasonable to use food sources of vitamin B-12 on a daily or several-times-weekly basis. Sources include Vegetarian Support Formula nutritional yeast, vitamin B-12 fortified soy milk, fortified meat analogs, and fortified breakfast cereals.
