Couldn't find any papers examining the stomach acid (hydrochloric acid) levels of ME/CFS patients when I searched just now, which is surprising. This would appear to be an area that needs to be better investigated.
Anecdotally it seems that ME/CFS can experience low stomach acid (hypochlorhydria). I appear to suffer from it.
There is a very simple home test for low stomach acid: the burp test for low stomach acid. To do this test, you only need some bicarbonate of soda. I have performed this burp test a few times, and my results show I have low stomach acid.
The Burp Test For Low Stomach Acid: How To Do It:
When you get up first thing in the morning, before eating or drinking anything:
• Mix ¼ teaspoon of bicarbonate of soda (sodium bicarbonate) into a glass of cold water (around 150 ml of water), and drink it down in more-or-less one go.
• Time how long it takes for you to burp.
• After five minutes of timing, the test is complete.
If your stomach acid production is normal, your first burp will appear within 2 or 3 minutes. But if your first burp appears after the 3 minute mark, this indicates a low stomach acid level.
For higher accuracy, it is a good idea to repeat this burp test over several mornings, and take the average result.
When I took this burp test myself, I did not burp at all within the 5 minute period of the test, and barely burped even after that period. Repeating this test the next morning, I also had the same results. So that definitely seems to indicate low stomach acid in my case.
It may be a good idea to set up a poll on this forum, asking people if they have low stomach acid, as measured by the burp test. Many people will already some bicarbonate of soda in their kitchen (and if not, a jar just costs around £1), so this burp test is not only very easy to do, it is also very cheap.
In Dr Myhill's article on hypochlorhydria (also available
here) she states that the symptoms of low stomach acid include:
Dr Myhill states that the possible problems that could arise from hypochlorhydria are:
A while ago I was working on a theory that
low stomach acid and
low pancreatic enzymes might result from the
dysautonomia that many ME/CFS patients have. Since both the
parietal cells that secrete stomach acid, and the pancreas that secretes digestive enzymes, are controlled by the parasympathetic nerves, any disruption to the parasympathetic nervous system may conceivably lead to reduced stomach acid and pancreatic enzyme secretion.
Many ME/CFS patients have
autoantibodies to the muscarinic acetylcholine receptors found on the parasympathetic nerves (some refs given
here), so if these anti-muscarinic autoantibodies are impeding parasympathetic nerve function, and thereby preventing the activating nerve signals getting through to the parietal cells and the pancreas, you might expect low stomach acid secretion, and low pancreatic enzyme secretion.
Though as
end mentioned
above,
gut pathogens might also affect the parietal cells. It is interesting that Dr Chia found that in his stomach biopsy research on ME/CFS, 82% of ME/CFS patients had evidence of enterovirus infection within their parietal cells in the stomach, compared to only 20% in the controls.
ᐞ So I wonder if this enterovirus infection in the stomach acid-producing parietal cells of ME/CFS patients may impede to function of these cells, leading to low stomach acids levels.
And according to Dr Lapp,
antibodies directed against thyroid and parietal cells are not uncommon in ME/CFS patients. So the immune system may be attacking your stomach acid-producing parietal cells (I guess this immune attack might be expected if these parietal cells are infected with enteroviruses).