What is Histamines Intolerance?

Histamine is a key chemical produced by the body for various functions, like communicating messages to the brain, triggering the stomach to produce acid for digestion, and being a part of the immune response to an allergy or injury. Histamines intolerance is the accumulation of histamine and the body’s incapability of histamine breakdown, which may increase the risk of histamine toxicity in the body. It is not a sensitivity towards histamine compounds, but rather an indication of histamine build-up. Several factors that can lead to histamines intolerance are drugs like antibiotics and antidepressants, a constantly stressful lifestyle, nutritional deficiencies, medical illnesses, and diet. Certain individuals may also develop histamine intolerance due to an imbalance of the microbiome in the gut, as gastrointestinal health can affect an individual’s tolerance towards histamine.

How It Affects Your Body

Histamine intolerance (HIT) is a result of an imbalance between the amount of accumulated histamine and the body's ability to degrade histamine.

In a healthy individual, histamine is broken down on a regular basis by two enzymes: diamine oxidase (DAO) and histamine N-methyltransferase (HNMT). The mechanism of HIT is proposed to be a result of an impairment in one of these two enzymes, either genetically or acquired later in life.

DAO is produced in the intestine, hence, if one's intestinal function is compromised, there may not be sufficient DAO to break down histamine normally. When histamine levels get too high, it will result in histamines intolerance and affect normal bodily functions. If an individual eats foods rich in histamine, alcohol, or drugs that release histamine or blocks DAO, it will also cause the symptoms to increase or worsen as excessive undegraded histamine will be absorbed by the body.

Signs and Symptoms