Allergic diseases may be due in part to too few antioxidants in the diet, doctors in one study said. Researchers measured the diets and followed 861 children for eight years from birth. As levels of the antioxidant beta-carotene in the diet increased, allergy decreased. Those who consumed the most beta-carotene were 20 percent less likely to have allergy than those who got the least beta-carotene. Scientists also found fewer signs of allergic stress (antibodies) in kids who got the most beta-carotene.