Food allergy or food intolerance

Food allergy is common problem with many people convinced that they suffer from one form of food allergy or another. But new studies show that food allergy is not as widespread as believed and that much of the self-diagnosed food allergies, could in fact be just food intolerance.

New studies by researchers at the Chicago and Northwestern University in the US, suggest that while almost 1 in 5 adults in the US think they have a food allergy, only 1 in 10 actually do. The study analyzed data from a representative survey that collected information from more than 40,000 adults.

Of all survey respondents, even among those who reported symptoms that seemed consistent with a food allergy, specialists diagnosed allergies in only around half of them. Also, among people with clinically diagnosed food allergies, under 25 percent were taking epinephrine, a drug used to treat severe allergic reactions.

The study showed that while an estimated 26 million people in the US suffer from food allergy, nearly double that number believe they are allergic to certain foods. Most of the people who believe they have a food allergy were found to be intolerant to a specific food, or suffering from some other food related issues.

A food allergy is different from food intolerance. In a food allergy, a protein causes an allergic reaction, known as an immune response. An ‘allergen’ is the protein that causes the food allergy. Allergens themselves are not harmful substances. Most people can be exposed to them without any adverse effects. They are called allergens because they affect some people by triggering a response in their immune system.

A food intolerance usually means that the person has an enzyme deficiency, so that their bodies cannot digest the food properly. Food intolerance may also be caused by certain chemicals in foods, by food poisoning due to the presence of toxins, by the natural occurrence of histamine in some foods, by salicylates which are present in many foods, and by food additives.

Onset of symptoms for food allergy and intolerance are also different. Food allergy symptoms appear soon after eating the food, while food intolerance symptoms appear later. The amount of food consumed for symptoms to appear are also different between food allergy and food intolerance. Food allergy can arise from consuming even a small amount of the allergen, the allergic person could have a reaction even if a food is prepared in an environment which contained the allergen, or if they enter a place where the allergen is present.

Meanwhile, someone with food intolerance can eat a small quantity of the food without any adverse reaction. The main symptoms associated with food intolerance are related to the gut and include intestinal gas, abdominal pain, or diarrhea.

Prevalence of food allergies are reportedly increasing worldwide, the US Food and Drug Administration (FDA) lists eight common allergenic foods: milk, eggs, fish, shellfish, peanuts, wheat, soybean and tree nuts such as walnuts. According the FDA these eight foods and their derivatives are responsible for around 90 percent of all allergic reactions in the US.

Among food allergies the most common were: Shellfish (7.2 million), milk (4.7 million), peanuts (4.5 million), tree nuts (3 million), fin fish (2.2 million), eggs (2 million), wheat (2 million) and soybean (1.5 million).

Reactions to food allergies could be uncomfortable, but not dangerous, such as itchy skin and diarrhea; or they could be anaphylactic, a potentially life-threatening reaction. In anaphylaxis, the body overreacts to the allergic food (allergen) causing extreme symptoms in different part of the body at the same time and requires immediate medical intervention.