The connection between gastric acid, histamine, antihistamines and proton pump inhibitors
In reponse to a question about gastrointestinal problems, Dr Janice Joneja discusses the connections between gastric acid, histamine, antihistamines and proton pump inhibitors. As she says, it is a topic that peope do find very confusing....

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Dr Janice Joneja, a world expert on histamine intolerance, has created an easy-to-read guide to help you understand whether you might be histamine intolerant, and, if so, what you can do about it.
Buy the paperback from Amazon here is the US – and from Amazon here in the UK. For elsewhere in the world, just 'search' your local Amazon store.

Buy the e-book from Amazon here in the US and from Amazon here in the UK. For elsewhere in the world, just 'search' your local Amazon store.


Question:

I am a 31 year old male.

Hello, my brief history is a healthy, diverse diet and body since May of this year. Since then, I've had some mild-moderate symptoms of excess air, burping, stomach growling, flatulence, distention and gut/chest pain. I had an upper scope done and results were negative with mild issues that didn't pick anything out. The doctor only recommended I continue my Prilosec for a month (I used it for 2 weeks from my general doctor prior) and work really hard not to swallow excess air...

2 weeks in I stopped meds after I was reading some food-gut related articles about meds like Prilosec don't help issues and only suppress them.

A few days later, I've mainly been sticking with a rather plain diet since May (rice, ginger, toast, salmon, oatmeal, broiled chicken, etc). Recently, I also started adding Greek yogurt and kefir after hearing about those benefits.

If I should find out if histamine intolerance (or any similar rare/misdiagnosed condition) could be sneaking up on me (or it comes and goes, like the wind), should I simply request a referral to a specialist from my general doctor?

Dr Joneja says:

Your symptoms do suggest that dysfunction in the stomach is probably contributing to your symptoms. I wonder what event just prior to the onset in May could have triggered the reaction? Investigation of the possible triggers might give you a better perspective on the options available to you. Infection, especially by Helicobacter pylori and stress, among others might be worth investigating, if you have not already done so. 

You are questioning the possible role of histamine in your symptoms, so I am going to take this opportunity to discuss a little of the science behind the connection between stomach problems and histamine, which my patients have often questioned. 

Gastric (stomach) acid is required for the first stage of protein digestion. The high acidity of the stomach initiates hydrolysis (chemical breakdown) of proteins in foods. This weakens the linkages between molecules, making the protein more accessible to pancreatic proteolytic (protein degrading) enzymes that act in the small intestine. This breakdown into small polypeptides and amino acids is required before they can be absorbed into circulation. Histamine is responsible for the first stage in the release of gastric acid. 

In order to carry out this process, histamine needs to couple to a special receptor on epithelial cells of the stomach, called parietal cells. After activation, the parietal cells secrete hydrochloric acid and intrinsic factor.  As in all its diverse roles in the body, histamine must attach to a special receptor molecule on the cell in which it functions.  There are 4 known receptor molecules, named H1, H2, H3 and H4, associated with different cells and processes.  Parietal cells of the stomach express the H2 receptor. 

The symptoms of allergy and inflammation, mediated by histamine, result from histamine coupling with H1 receptors on the reactive cells.  Antihistamines, which structurally mimic the histamine molecule, attach to the H1 receptor, effectively blocking the attachment of histamine molecules and preventing their activity. Thus, antihistamines stop the symptoms for which histamine is responsible, but do not inhibit the production and release of histamine. However, antihistamines cannot block the H2 receptor, which has a different conformation, and therefore are of no value in preventing activation of the process of gastric secretion.

Molecules that can couple with the H2 receptor were developed in the 1960s.  The first, Cimetidine, was marketed as Tagamet; later Ranitidine (marketed as Zantac) was developed. These are still used to treat conditions such as dyspepsia.

A much more powerful inhibition of gastric acid secretion (up to 99% inhibition) can be achieved with the newer proton pump inhibitors, developed and marketed from the late 1980s and onwards. Proton pump inhibitors intercept the secretion of gastric acid from the parietal cells at a different stage of the process. Whereas histamine receptor blockers prevent the initial stage of acid secretion, proton pump inhibitors block the final stage. They inhibit the enzyme system which is responsible for the movement of acid molecules into the lumen of the stomach. Prilosec (omeprazole) is one of several proton pump inhibitors now commonly used in the treatment of a number of conditions involving the adverse effects of gastric acid such as dyspepsia, esophagitis (oesophagitis) of various types, peptic ulcers and other causes of gastritis.

You do not mention whether the Prilosec helped in the management of your symptoms. You state that you did not like the idea of the proton pump inhibitor, and perhaps would prefer a more “natural” way of control. If Prilosec did help, would you consider trying an H2 blocker such as Zantac or Tagamet in order to reduce the secretion of gastric acid? Have you discussed that with your doctor?

You have questioned the possibility of histamine intolerance contributing to your symptoms. Because of the important role of histamine in gastric acid secretions, it would be a good idea to investigate this further. However, there are no tests which can accurately diagnose histamine intolerance; the most effective method for determining a possible histamine sensitivity is to undertake a histamine restricted diet for a trial period. Follow the directives of foods to avoid, and consume those allowed, for a period of 2-4 weeks. If you experience symptomatic relief you may assume that histamine sensitivity is contributing to your condition and will be able to control your symptoms for the long term. You can find detailed information about histamine sensitivity or intolerance in my books and articles.

Detailed information about which foods are allowed and restricted on the diet can be found in my book, “Dealing with Food Allergies” and the consumer factsheet associated with “The Health Professional’s Guide to Food Allergies and Intolerances”. You can buy all of Dr Joneja's books here in the UK or here in the US.

As a final note, yogurt and kefir are contraindicated on a histamine-restricted diet since both contain histamine as a result of the fermentation process involved in their manufacture.

March 2016


Purse

Dr Janice Joneja, a world expert on histamine intolerance, has created an easy-to-read guide to help you understand whether you might be histamine intolerant, and, if so, what you can do about it.
From Amazon here in the US – $7.72
From Amazon here in the UK – £5.99


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.

For many, many other articles on every type of food allergy and intolerance click here; for coeliac disease and other food related conditions, go here.

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Dr Janice Joneja, Ph.D., RD

Dr. 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). 

She has been a member of the faculty at several Canadian universities, starting her career as an Assistant Professor in the Department of Microbiology, Faculty of Science, and in the Faculty of Dentistry, at the University of British Columbia, Vancouver. Since 2001 Dr. Joneja has been a faculty member in the School of Biomedical and Molecular Sciences, at the University of Surrey, in England, teaching in the M.Sc. course in Nutritional Medicine.  For 12 years she was head of the Allergy Nutrition Program at the Vancouver Hospital and Health Sciences Centre.

Dr. Joneja is the author of six books and a dietetic practice manual on food allergy, a textbook on Irritable Bowel Syndrome, and several distance education courses. Her most recent books include “The Health Professional’s Guide to Food Allergies and Intolerances”, “Dealing with Food Allergies”, and “Dealing with Food Allergies in Babies and Children”.  Dr. Joneja’s work has been published in peer-reviewed scientific and medical journals, as well as in popular magazines.  She is a respected lecturer at universities, colleges and hospitals internationally, and regularly appears on television and radio call-in shows as an expert in her field.

Dr. Joneja is President of Vickerstaff Health Services, Inc., a practice that provides counselling for people suffering from all aspects of adverse reactions to food, and resources for the professionals and care-givers who support them.

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