Some kids can have diarrhea after consuming a glass of milk. These kids might have lactose intolerance, which is caused by problems digesting lactose, the main sugar in milk. Lactose intolerance is the most common food intolerance, which has similar causes and symptoms to a food allergy.
Food intolerance is a negative reaction in the digestive system, rather than an immune system response, to certain foods as the result of the limited capabilities of the gastrointestinal tract to digest some substances.
People who have a food intolerance may be able to eat some amounts of the offending food without trouble. If you have a food intolerance, you may have some discomfort within few days after consuming the food. Although it causes discomfort, a food intolerance is never life threatening.
Unlike an intolerance to certain foods, a food allergic reaction involves the immune system which will react to the allergen (a substance that causes an allergic reaction). An allergic food reaction can be severe or life threatening. Food allergies can be triggered by even a small amount of the food. The symptoms of food allergy may include swollen lips, shortness of breath, or vomiting.
Causes of food tolerance
Food intolerance can be caused by many factors, for example: Food additives, such as monosodium glutamate/MSG and sulfites, which are used to preserve dried foods, canned goods, wine, and inhibit yeast growth.
Also, salicylates, a group of chemical derived from salicylic acid found naturally in certain foods like fruits, vegetables, nuts, coffee, juice, beer, and wine, and also synthetically produced for use in product like aspirin.
Thus, a salicylate-containing food may trigger allergic reaction on people who are sensitive to aspirin. Obviously, consuming any food in an excessive amount can cause gastrointestinal problems.