Food allergies
Food allergy is an abnormal response to a food triggered by the body’s immune system. Allergic reactions to food can cause serious illness and, in some cases, death. Anaphylaxis is the term for a deadly food allergy reaction, with tree nuts (e.g., walnuts) and peanuts as the leading causes for anaphylaxis. If you think you may have a food allergy, it is important to work with your doctor or health care provider to find out exactly what food(s) cause the allergic reactions. They may start, for example, with a detailed history or a differential diagnosis, looking specifically for evidence of reactions and food.Food allergens are proteins within the food that enter your bloodstream after the food is digested. From there, they go to target organs, such as your skin or nose, and cause allergic reactions. An allergic reaction to food can take place within a few minutes to an hour. The process of eating and digesting food affects the timing and the location of a reaction.
If you are allergic to a particular food, you may first feel itching in your mouth as you start to eat the food. After the food is digested in your stomach, you may have gastro-intestinal (GI) symptoms such as vomiting, diarrhea, or pain. When the food allergens enter and travel through your bloodstream, they may cause your blood pressure to drop. As the allergens reach your skin, they can cause hives or eczema, and when allergens reach your lungs, they can trigger asthma.
Food intolerance
Sometimes, a reaction to food is not an allergy at all but instead called “food intolerance.” Food intolerance is more common than food allergy. The immune system does not cause the symptoms of a food intolerance, though these symptoms can look and feel like those of a food allergy.Examples of food intolerance include issues like food poisoning, caused by food contaminated with microbes or toxins; histamine toxicity, where histamines present in the foods themselves can cause a reaction that mimics an allergy; or lactose intolerance, where there is not enough of the enzyme lactase in order to break down lactose, which can cause bloating, stomach pain and diarrhea.
In addition, there are other reactions to food additives or food substances that, while not technically a food allergy, can produce symptoms sometimes associated with food allergies. One example is a symptom of headaches and a warm sensation, associated to food intolerance of MSG (monosodium glutamate), a food additive. Some people with severe asthma may experience a tightening in the chest (or bronchospasms) if they consume high concentrations of sulfites, which are sometimes an additive to or naturally occuring in food (and beverages like wine).
The U.S. Food and Drug Administration (FDA) requires ingredients in a packaged food to appear on the label. Read food labels carefully and avoid restaurant-prepared foods that might have ingredients that would affect those for whom food intolerance is a problem. If you do dine out, be sure to ask how the food is prepared.
