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Histamine Intolerance

Histamine Intolerance

Do You Have Histamine Intolerance? Nutrition Can Help!

Histamines, a natural part of your immune system, are released as a reaction to help rid substances that your body perceives as foreign.

However, if you are a person with food sensitivities or environmental sensitivities, you may have an overactive histamine response (overactive defense system), also called Histamine Intolerance or HIT.

Histamine Intolerance is mainly caused by an imbalance of histamine intake and the capacity for histamine metabolism and degradation.

If you have too much histamine in your body it can contribute to annoying symptoms like runny nose, red eyes, itchy skin or hives. Or, your body might respond with more serious stomach pain, diarrhea, nausea, sleep difficulties, or even migraine headaches.

(For a comprehensive view of histamine triggers and symptoms, see the flow chart on Histamine Intolerance & Mast Cell Activation, below.)

The Histamine Cascade Sequence….From Mast Cells to an Out of Control Inflammatory Response

When there is a foreign intruder, the body first sends a chemical signal to a type of white blood cell called mast cells, to release histamines. These mast cells are located in  your skin, lungs, nose, mouth, gut, and blood. When the histamines are released they dock at receptors in your body.

The histamines then send out a signal to boost blood flow in the area of your body affected which in turn launches an inflammatory response.
Inflammation is a natural, healthy response that signals other chemicals from your immune system to step in to do repair work. However, with histamine intolerance, the inflammatory process gets out of control, histamines build up, overwhelming the body’s ability to clear histamines and keep the amount of histamines in balance. 
How Does Your Body Get Rid of Histamine?
DAO Enzyme
Your body gets rid of food derived histamine in your gut through a chemical reaction that requires an enzyme called DAO (diamine oxidase).You naturally make this DAO enzyme in our intestinal mucosa cells. It is also available as a DAO dietary supplement (Histamine Digest).
However, you can have low DAO enzyme activity for many reasons, including poor gut health and inflammatory GI diseases that affect the integrity of the gut lining. (We also naturally make less DAO as we age!)
The unmetabolized histamine can then enter the bloodstream increasing its plasma concentration. Once located in blood it spreads throughout the body.
HNMT Enzyme
A second pathway also degrades/metabolizes histamine — HNMT – Histamine N-Methyltransferase enzyme. HNMT is not gut-specific and works throughout the body.
As you can see in the illustration below, both histamine pathways require the assistance of nutrient cofactors like copper, iron, B vitamins, vitamin C and SAMe (a supplier of methyl groups).
— based on information from The International Society of DAO Deficiency

Biochemically Speaking…How the Body Clears Histamines

Histamine Biochemistry and DAO


 The body breaks down of histamine in the body through two pathways:

      1. via the enzyme DAO in the gut, or
      2. via the enzyme HNMT in the rest of the body.

Your Cup Runneth Over — Supporting a Healthy Response to Histamines

The body’s tolerance for histamines is an additive effect. Many sensitive people may handle smaller amounts of histamine just fine.
In addition to certain foods triggering a histamine response, some foods are also naturally high in histamines.
People with histamine intolerance (HIT) need to limit their intake of high histamine foods like aged and fermented foods such as aged cheeses, processed luncheon meats, fermented vegetables, red wine and leftover foods.
Some people with histamine intolerance may not make enough of their own DAO enzyme; a DAO enzyme supplement can be taken to boost the amount of DAO in the body.

Diet and Supplements to Manage Histamine Intolerance

I work with clients who have an overactive histamine response. First I help them to manage their symptoms through diet and nutrition supplements.
However, as a functional nutritionist, I also address the underlying root cause of the out of control histamine response and help to restore gut health and support healthy gut microbial ecosystem.
I address the problems at each step of the Histamine Intolerance cascade, on a biochemical and physiological level, short and long-term:
  • reducing intake of high histamine foods (including alcohol which blocks DAO enzyme)
  • stabilizing the mast cells from releasing excessive histamines
  • blocking histamine receptor sites
  • supplementing with or supporting the enzymes like DAO that are responsible for degrading or mopping up excess histamine.
  • nutrigenomics to assess genetic SNPs in methylation related to enzymes that degrade histamine
  • long term restoration of gut health and addressing gut dysbiosis

Flow Chart on Histamine Intolerance (HIT) Which I Love!
This flow chart (from really illustrates the precedents, triggers and potential subsequent cascade of symptoms with Histamine Intolerance and Mast Cell Activation.

Want to know more about Histamine Intolerance and Health?

  • “Histamine Intolerance” translated from Cesk Fysiol, 2013;62(1):26-33, E Hanusková 1J Plevková
    Abstract: Histamine intolerance (HIT) is a pathological process that results from a disbalance between levels of released histamine and the ability of the body to metabolize it. Accumulated histamine leads to the onset of “histamine mediated” reactions which are usually excessive and decrease quality of life.

    Although we have a lot of knowledge about histamine intolerance, HIT is still vastly underestimated, because it manifests via the diversity of clinical symptoms, that are often misinterpreted by the patient and sometimes even by a physician.

    Clinical symptoms and their provocation by certain kinds of food, beverages and drugs are often attributed to the different diseases, such as food allergy and intolerance of sulfites, or other biogenic amines (eg. tyramine), mastocytosis, psychosomatic diseases or adverse drug reactions in general.

    Proper diagnosis of HIT followed by therapy based on histamine–free diet and supplementation of diaminooxidase can considerably improve patient’s quality of life.
  • The Many Effects of Histamine  – Monograph from Integrative Therapeutics
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