Each week a nutritionist from the University of Maryland Medical Center will provide a guest post. This week, Faith Hicks weighs in on food allergies.
Food allergies and food intolerances are easily confused, even by health care professionals.
A true food allergy is an immune response to a food. The immune system mistakes a food as a harmful substance and mounts a response, which could be life threatening. About 15 million Americans have a food allergy. Many people who think they have a food allergy actually don’t.
Symptoms of food allergy can vary. The most life-threatening reaction is anaphylaxis, which is swelling of the airway and difficulty breathing. Foods most likely to trigger this response are peanuts, tree nuts and occasionally milk, eggs, or seafood. Other allergic responses include rashes or hives, swelling of the lips, nausea or diarrhea. Sometimes gastrointestinal symptoms like heartburn, reflux, diarrhea or bloody stools, particularly in children, may be due to an allergic reaction. Even very small amounts of a food can cause an allergic reaction.
How are food allergies diagnosed and treated?
If you suspect you may have an allergy, see your doctor. If you think you have had a reaction, the next one may be more severe than before, so don’t delay. A skin prick or blood tests are used to identify IgE antibodies to a particular food; however, a positive test does not always mean that the food will cause a reaction. Therefore, IgE testing is correlated with symptoms of an allergy when a food is eaten. Sometimes a food challenge will be done in the physician’s office. The treatment for a food allergy is to remove all traces of the food from your diet. The Food Allergy and Anaphylaxis Network can be a great resource for learning to read labels, eat out and survive at school with a food allergy.
What is a food intolerance?
A food intolerance is an unpleasant or adverse reaction to a food, but is not immune related. Symptoms might be migraines, reflux or heartburn, or diarrhea. The most common intolerance is lactose intolerance. This is caused by a decreased or absent level of the lactase enzyme that digests lactose or milk sugar. The undigested lactose results in gas or diarrhea.
Individuals with food intolerances can usually handle a small amount of the food, but have unwelcome symptoms with larger amounts. If you are lactose intolerant, you may be able to have cream in you coffee, yogurt with active cultures, aged cheeses like cheddar and Swiss. Taking Lactaid pills or Dairy Ease may help you tolerate small amounts of lactose. Some people are able to use lactose-reduced milk and ice cream. Soy milk, soy cheese and soy ice cream would be good choices for those with more severe lactose intolerance.
Bottom Line: If you are experiencing any food-related symptoms, see your healthcare provider. It is best to seek professional advice before making any major changes in your diet.
Each week for about a year, the nutritionists from 
