Studies by Dr. S. Allan Bock of the National Jewish Medical and Research Center in Denver suggest that about 5 percent of all infants under 6 years of age likely risk known diverse reactions to foods.
But of these the most frequently encountered reaction (rash and/or diarrhea after being fed fruit juices) is likely to be non-allergic. Among older age groups, food sensitivities are likely to be considerably lower.
Prevalence of food sensitivities