Food allergy is sometimes confused with food intolerance.
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Lactose is a sugar found in milk and most milk products.Lactase is an enzyme in the lining of the gut that breaks down or digests lactose. Lactose intolerance occurs when lactase is missing. Instead of the enzyme breaking down the sugar, bacteria in the gut break it down, which forms gas, which in turn causes symptoms of bloating, abdominal pain, and sometimes diarrhea.
Lactose intolerance is uncommon in babies and young children under the age of 5 years. Because lactase levels decline as people get older, lactose intolerance becomes more common with age. Lactose intolerance also varies widely based on racial and ethnic background.
Your healthcare professional can use laboratory tests to find out whether your body can digest lactose.
Another type of food intolerance is a reaction to certain products that are added to food to enhance taste, add color, or protect against the growth of microbes. Compounds such as monosodium glutamate (MSG) and sulfites are tied to reactions that can be confused with food allergy.
These passing reactions occur rapidly after eating large amounts of food to which MSG has been added.
Sulfites can cause breathing problems in people with asthma.
The FDA has banned sulfites as spray-on preservatives for fresh fruits and vegetables. When sulfites are present in foods, they are listed on ingredient labels.
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Gluten is a part of wheat, barley, and rye. Gluten intolerance is associated with celiac disease, also called gluten-sensitive enteropathy. This disease develops when the immune system responds abnormally to gluten. This abnormal response does not involve IgE antibody and is not considered a food allergy.
Some of the symptoms of food allergy, such as abdominal cramping, are common to food poisoning. However, food poisoning is caused by microbes, such as bacteria, and bacterial products, such as toxins, that can contaminate meats and dairy products.
Fish, such as tuna and mackerel that are not refrigerated properly and become contaminated by bacteria, may contain very high levels of histamine. A person who eats such fish may show symptoms that are similar to food allergy. However, this reaction is not a true allergic reaction. Instead, the reaction is called histamine toxicity or scombroid food poisoning.
Several other conditions, such as ulcers and cancers of the gastrointestinal (GI) tract, cause some of the same symptoms as food allergy. These symptoms, which include vomiting, diarrhea, and cramping abdominal pain, become worse when you eat.
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Last Updated December 02, 2010