Mechanisms of Food Reactions

We discussed the basic definitions on the previous page, lets dive a little deeper into these mechanisms.

Food Intolerance

Food intolerance refers to difficulty digesting certain foods, which can cause symptoms such as bloating, gas, diarrhea, and abdominal pain. This is typically due to a lack of specific enzymes needed to properly digest certain foods. For example, lactose intolerance is a common type of food intolerance caused by a lack of lactase, the enzyme needed to break down lactose in milk. Other examples of food intolerance include fructose malabsorption, which occurs when the body has difficulty digesting fructose, and histamine intolerance, which occurs when the body has difficulty breaking down histamine in certain foods.

Food Sensitivity

Food sensitivity refers to a delayed, non-IgE immune reaction to specific foods, which can cause a range of symptoms such as headaches, joint pain, and fatigue. These symptoms can occur hours or even days after eating the offending food. Food sensitivities are thought to be caused by an abnormal immune response, in which the immune system mistakenly identifies a food as a foreign invader and mounts an attack against it. This response can lead to inflammation and tissue damage, which can cause a wide range of symptoms.

The mechanism of food sensitivity is not well understood, but it is thought to involve a type III or type IV hypersensitivity reaction. In a type III hypersensitivity reaction, immune cells known as B cells produce antibodies that bind to specific proteins in the food, forming immune complexes that can trigger inflammation and tissue damage. In a type IV hypersensitivity reaction, immune cells known as T cells mount an attack against specific proteins in the food, which can also trigger inflammation and tissue damage.

Food Allergy

Food allergy is an immediate, IgE-mediated immune response to specific foods, which can cause symptoms such as hives, swelling, and anaphylaxis. These symptoms typically occur within minutes to hours of exposure to the offending food. Food allergies are caused by an overreaction of the immune system to specific proteins in certain foods.

In a food allergy, the immune system produces IgE antibodies in response to specific proteins in the food. When the person eats the food, the IgE antibodies trigger the release of histamine and other chemicals, which can cause a wide range of symptoms. Anaphylaxis is a severe and potentially life-threatening allergic reaction that can cause symptoms such as difficulty breathing, loss of consciousness, and shock.