Heartburn is Caused by Low Stomach Acid, Not High

Ask most people on the street what causes heartburn, and they’ll tell you without thinking: “too much stomach acid.” Not only does this seem like a simple and rational link, years of Gaviscon commercials have left us with this idea set in stone.

There is only one problem. Heartburn is not caused by high levels of hydrochloric acid. It’s the exact opposite. Let me explain. Hydrochloric acid is incredibly caustic; it has a pH of 1 and is strong enough to digest a two pence piece. It figures that it can easily burn through flesh. Luckily, the stomach produces a thick mucus to protect itself (and you) from the potentially negative impact of the acid.

This is why a continual and plentiful supply of hydrochloric acid causes no problems, yet a period that sees little or no acid produced results in issues. This is because there is little or no stimulation of the gastric mucosa, resulting in an extremely thin covering or gaps in the protection. It is now inevitable that even small amounts of acid can gain access to unprotected flesh. Pain is the result.

But your acid status goes much further than whether or not you have heartburn or not. Hydrochloric acid is required for:
- the ionization of minerals (without which, they cannot be efficiently absorbed)
- the breakdown of proteins (necessary for absorption in the intestines)
- the activation of digestive enzymes
- the release of bile from the gall bladder
- the control of intestinal bacteria
In short, every single step in the digestive process is affected by your hydrochloric acid status. It therefore follows that suppressing it will cause problems. This may range from more objective issues such as poor-quality nails and hair or low vitality to more measurable problems, such as anaemia or small intestinal bacterial overgrowth (colloquially dubbed “candida”). Poor sleep is almost guaranteed, as magnesium levels drop progressively lower.

A recent case (one that prompted me to write this article) summarises the issue perfectly. The individual was a man in his 30s. He had suffered from some severe digestive issues for the last decade, and his health had recently taken a turn for the worst with issues such as anaemia and insomnia affecting his ability to do his job. The client was actually a doctor who, in a long-standing tradition of medicine, had self-prescribed a number of supposedly benign medications in a bid to manage the problems. The list was headed by omeprazole but also included mirtezepine to address his sleeping issues.

I explained the 10 years he had spent on omeprazole almost certainly triggered the problems that occurred later on. As you can imagine, as someone who admittedly ‘could not live without it’ and someone who had prescribed this drug to hundreds of others, my client had a hard time taking this on board. The question was one I had heard many times before: “But, if heartburn is caused by low acid, then why does an antacid deal with it so effectively?”

As explained above, I outlined how even tiny amounts of acid can cause pain when exposed to unprotected flesh. Taking your acid levels from 5% of their optimum level to 0% therefore will offer temporarily relief. I then offered the following questions: if heartburn is caused by high acid, why do more old people suffer from it when they are the population known to have the lowest levels of acid? If lowering stomach acid was helpful long-term, why is the problem normally worse when people discontinue the medications?

I am sure that that I will have this discussion many more times before the medical establishment start to put into practise these better habits on managing heartburn and Gaviscon adverts are banned. The sad thing is that this is not new; Jonathan Wright, a naturopathic doctor based in Washington, has been educating the medical community on the issue since the 70s. I have been testing for stomach acid since 2007, and yet to find a single individual with too much.

The good news is that it is easy to determine an individual’s need for Hydrochloric Acid. The simplest option involves the HCL Challenge test which uses HCL supplements, gradually increasing the dose until it symptoms of excess acid appear. You can also conduct home tests using baking soda to see how long it takes to belch. Other options involve testing for salivary VEGF or using the Heidelberg test; this latter represents the most costly of all options and involves swallowing a capsule with a radio-transmitter.

In any case, there is no excuse for making uninformed guesses and risking years of incomplete digestion and the serious health problems this causes. Blocking the pain is not the same as dealing with the problem; don’t become another antacid victim.


  1. Nigel says

    Hi, interesting article and not the first time I have read about there not being enough acid …..
    I was diagnosed with GERD some years back and usually experience heart burn after a very heavy carbohydrate meal in the evenings.
    Even when eating nuts, oils and vegetables I still feel nauseous but without the heart burn.
    I have resisted taking prescribed drugs.

    Will taking supplements to increase acidity stimulate the stomach to start producing more acid or would the recipient have to rely on supplements indefinitely?

  2. Marek says

    Hi Nigel, HCl supplements are normally required for around 6-7 months until the individual starts producing their own stomach acid again… however, I should point out that this normally is the result of dealing with the stressors that shut down their acid production in the first place (eg. adrenal issues, poor sleep, chronic infection, etc). So dealing with the root cause + short-term supplementation is the way to go. Regards, Marek

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