Physical reactions to certain foods are common, but most are caused by a food intolerance rather than a food allergy. A food intolerance can cause some of the same signs and symptoms as a food allergy, so people often confuse the two. A true food allergy causes an immune system reaction that affects numerous organs in the body. It can cause a range of symptoms. In some cases, an allergic reaction to a food can be severe or life- threatening. In contrast, food intolerance sym