Dr Joneja's Guides to Histamine Intolerance
Dr Janice Joneja, a world expert on histamine intolerance, has published two books on histamine intolerance:
A Beginner's Guide to Histamine Intolerance – read more about it here.
Histamine Intolerance: The Comprehensive Guide for Healthcare Professionals – read more about it here.
Buy the ebook from Amazon here.
|Can antihistamines be used to control a histamine intolerance?|
A questioner wanted to know whether taking antihistamines would either reduce one's intolerance to histamines, or would make a low histamine diet work more efficiently. Dr Joneja says....
The answer to your question requires an understanding of the way in which antihistamines work.
First of all, let us consider how histamine acts in the human body. Histamine begins its activity by coupling to a specific receptor molecule on the surface of the cell on which it exerts its function. The histamine molecule joins with the receptor like a key in a lock. In coupling with the receptor, histamine “unlocks” the cell’s function. There are 4 distinct types of histamine receptors on different types of cells in the human body, labelled H1, H2, H3, and H4. H1 receptors occur on cells where histamine is involved in inflammation and allergy. H2 receptors occur on cells in the stomach where histamine triggers the release of gastric acid, which is essential in proper digestion. H3 receptors are present on cells of the central and peripheral nervous systems where histamine acts as a neurotransmitter. The H4 receptor is found on cells in various organs where histamine controls certain characteristics of granulocytes such as mast cells, eosinophils and neutrophils, among others.
Antihistamines are designed to combat the adverse symptoms of histamine in allergy and inflammation, so are designed only to control the function of cells which have H1 receptors. They act by preventing histamine from reaching the cell by blocking the receptor. The shape of the active molecule in an antihistamine exactly mimics the part of histamine that couples with the receptor. It is like making a key in exactly the same shape as the histamine key, which will fit into the lock, but which will not unlock the cell’s function. So, taking an antihistamine in treating allergy or inflammation will prevent histamine from reaching the cells involved, thereby reducing or completely alleviating the symptoms. However, antihistamines do not stop the release of histamine from mast cells, which are responsible for production of the amine. Therefore, the same amount of histamine will be circulating in the body as before taking the antihistamine; it is simply prevented from exerting its effects. As soon as the antihistaminic effects wear off, histamine will couple to the available receptors and symptoms will recur.
So - a simple answer to your question: antihistamines stop the activity of histamine for as long as their activity continues. When the antihistamine is no longer present in an amount sufficient to block histamine receptors, histamine will again cause problems as its level will not have decreased from pre-treatment levels. If the bucket was full before, it will still be full after taking the antihistamine.
Following a histamine-restricted diet will reduce the amount of histamine entering the body (exogenous histamine), thus decreasing the total level of histamine. In many cases this will be sufficient to reduce the symptoms of histamine sensitivity as long as any cause of histamine release within the body (endogenous histamine) has been addressed.
For a low histamine diet see the second half of this article.
If you found this article interesting you can find a number of other articles on histamine intolerance both by Dr Joneja and others here, reports on histamine research here and a Q & A section on histamine with Dr Joneja here.
To sign up for our FREE fortnightly e-newsletter, go here.
Dr Janice Joneja, Ph.D., RDDr. Janice Joneja is a researcher, educator, author, and clinical counsellor with over thirty years of experience in the area of biochemical and immunological reactions involved in food allergy and intolerances. Dr. Joneja holds a Ph.D. in medical microbiology and immunology and is a registered dietitian (RD).