Food allergy is different from food intolerance, and the term is sometimes used in a vague, all-encompassing way, muddying the waters for people who want to understand what a real food allergy is. The difference between an allergy and an intolerance is how the body handles the offending food. As the battle rages, symptoms appear throughout the body. The most common sites are the swelling of the lips, stomach cramps, vomiting, diarrhea, hives, rashes or eczema, and wheezing or breathing problems. People with allergies must avoid the offending foods altogether.
Food intolerance is a much more common problem than allergy.
Here, the problem is not with the body's metabolism and not its immune system. The body cannot adequately digest a portion of the offending food, usually because of some chemical deficiency. The deficiency can cause cramps and diarrhea if milk is consumed. Estimates are that about 80 percent of African-Americans have lactose intolerance, as do many people of Mediterranean or Hispanic origin. It is quite different from the true allergic reaction some have to the proteins in milk.