With certain exceptions (such as sensitivities to lactose and gluten, both of which have a genetic basis), food intolerances are often highly individual and mysterious. In some cases, they are due to physical or emotional stress or exposure to environmental toxins rather than a reaction to the foods themselves. Lactose intolerance results from a deficiency of the enzyme lactase, which is needed to digest the sugar in milk. At least one out of 10 people worldwide shares this deficiency and develops bloating, abdominal pain and, often, diarrhea when consuming milk. Gluten intolerance is caused by an abnormal immune response to the major protein in wheat and some other grains.
I recently revisited the issue of food sensitivity testing with Randy Horwitz, M.D., Ph.D., medical director of the Andrew Weil Center for Integrative Medicine at the University of Arizona, who specializes in immunology. We agree that the only reliable approach to determining food intolerances or sensitivities is to use avoidance and provocative food intolerance testing – in other words, an elimination diet followed by a “challenge” to see whether a suspect food really does set off a reaction.
