Though uncommon, food allergies can have serious consequences. The incidence of true food allergy is about 1% to 2% in adults, and 5% to 8% in young children. Often soymilk and tofu can take the place of the more allergenic foods, such as cow's milk and eggs. However, some people are also allergic to soy. Those who are allergic to soy may be able to tolerate some soyfoods, but not others.

It is important for these people to read food labels and familiarize themselves with the ingredients. Children often outgrow their allergies within a few years. The most common food allergies are to cow's milk, eggs, peanuts, and fish, although any food can be potentially allergenic.

The best treatment for a food allergy is complete avoidance of the allergenic food. This means that alternative foods must be found to provide the missing nutrients. Identifying alternative foods is especially crucial in the case of young children because they are in a phase of rapid growth and development.

Soy-based infant formulas have been used since 1929 to feed infants with cow's milk protein allergies. Today's soy formulas are equivalent to cow's milk formulas in digestibility, nutritional profile, and acceptability. In healthy infants, soy formulas promote normal growth, nutritional status, and bone mineralization.