Food allergies are abnormal responses of the body's immune system to certain foods or food ingredients. Food allergies can show up as rashes, swelling of the skin, nasal congestion, nausea and diarrhea or the most serious reaction, anaphylactic shock, which is life threatening.

About 1 percent of adults suffer from food allergies, so knowing what to avoid is important. Most common allergens are peanuts, shellfish and eggs.

Food intolerances do not involve the immune system, but reactions can mimic those of allergies. With food intolerance, the body can't adequately digest a certain component of a particular food. Intolerances can involve many different foods, which makes it important to learn what substances trigger a reaction.

Food allergies and food intolerances should be diagnosed by a physician, and a dietetics professional can help develop an eating plan that's right for you.