People usually eat five food groups: protein, dairy, grains, fruits, and vegetables. Foods contain hundreds of natural chemicals including vitamins, minerals, carbohydrates, fats, protein, phenolics, terpenes, sugars, fatty acids, steroids, alkaloids, and many other compounds. While most foods benefit the body, some can trigger adverse symptoms known as an allergic reaction. It can be anaphylaxis or food sensitivity/intolerance. People can be allergic/sensitive to the food as well as to any/many of the compounds it contains, even vitamins and minerals This explains why people can react to a food they have never eaten, as many of these compounds repeat from food to food.
Food allergy among children is increasing. A recent CDC survey estimated that 1 in 20 US children have food allergies, which is a 50 percent increase from the late 1990s. The explanation for this is unknown and controversial. Consumption of processed food as well as the frequency with which any food is eaten may be playing a roll. Food allergies/sensitivities affect people causing a variety of symptoms in any body system.