The Truth About Stomach Acid: Why low stomach acid is jeopardizing your health

nexiumIf you have ever watched television during the weeknight evening hours or had your regular radio programming interrupted by some messages from the sponsors, it is likely that you have been inundated with a slew of advertisements for antacids and acid-suppressing drugs, including the “purple pill” (Nexium), Prilosec, Prevacid, Pepcid AC, Zantac, and numerous other medications that lower stomach acid. Understandably, you may be under the impression that the symptoms of heartburn, indigestion, and gastrointestinal acid reflux disease (GERD) are caused by too much stomach acid. As acid-suppressing drugs are among the most commonly used prescription and over-the-counter medications, the pharmaceutical companies are banking on acceptance of the idea that stomach acid is something that needs to be kept in check. However, in the reality that is not controlled by the powerful pharmaceutical industry and the conventional medical system (both of which have an interest in keeping you ill and dependent on medications), stomach acid is not something to be feared! It is much more likely that your symptoms are being caused by low stomach acid, instead of an overproduction of stomach acid.

Why stomach acid is important


In the infinite wisdom of the human body, the stomach was designed to produce the acid that is necessary for proper digestion of food. When functioning properly, the parietal cells of the stomach secrete hydrochloric acid that bring the stomach pH to a range of approximately 1.5 to 3.0. This is strong enough of an acid that if it were to be dropped on a piece of wood, it would burn a hole through the wood. The inner lining of the stomach is protected from its own acid by a thick layer of mucous and epithelial cells that produce a bicarbonate solution (an alkaloid) to neutralize the acid.

Stomach acid has several important roles including:

  • Breakdown of proteins into a form that they can be digested (called proteolysis).
  • Activation of the enzyme pepsin, which is responsible for protein digestion.
  • Inhibiting the growth of microorganisms that enter the body through food to prevent infection.
  • Signaling when the food (referred to as chyme) is ready to leave the stomach and move into the small intestine for continued digestion.

When the digestive system is functioning normally, food travels down the esophagus to the stomach. The stomach works to ensure adequate mechanical digestion (by churning of the stomach) and production of stomach acid until the chyme is brought to the proper pH level. At that point, the valve at the lower end of the stomach, the pyloric sphincter, is triggered to open and release the chyme into the small intestine. The pH level of the chyme entering the small intestine triggers the release of pancreatic enzymes (to continue with the digestive process) and sodium bicarbonate (to neutralize the chyme to prevent burning of the small intestine).

What happens when stomach acid is too low

When stomach acid production is low, dysfunction throughout the digestive system can occur, leading to numerous symptoms and disease processes. The body’s preference is to keep the chyme in the stomach until it reaches the proper pH level. Therefore, when stomach acid production is low, the chyme sits in the stomach for a longer period of time without the nutrients being broken down properly. At the same time, the low stomach acid promotes an environment that is more friendly to the growth of microorganisms, which are fed by the carbohydrates that become fermented from sitting in the stomach for too long. Eventually, excessive pressure from the bacterial overgrowth and maldigested food results.

The stomach has two valves, the lower esophageal sphincter (LES) (at the top of the stomach) and the pyloric sphincter (at the bottom of the stomach). While the pyloric sphincter is a one way valve, the LES is designed to open both ways. When excessive pressure builds up in the stomach, but the pH is still not at an optimal range to allow opening of the pyloric sphincter, the body identifies only one option to release the pressure: Open up the LES. Opening of the LES allows release of the pressure into the esophagus and that is what commonly leads to the symptoms of heartburn and acid reflux. Even if your stomach isn’t producing enough acid, any amount of acid going into the esophagus will result in uncomfortable symptoms because the esophagus is not designed to handle stomach acid. Frequent opening of the LES toward the esophagus will contribute to a weakened valve that compounds the problem.

**Note: There are also other causes that contribute to a malfunctioning LES. Certain foods (e.g. hot peppers, citrus, tomatoes), drinks (caffeine, alcohol), overeating, overweight and obesity, pregnancy, hiatal hernia, and many medications (including NSAIDs, antibiotics, bronchodilators, beta-blockers, calcium channel blockers, nitrates, antidepressants, anti-anxiety, and anticholinergics) are associated with a weakened LES.

Low stomach acid also contributes to digestive problems downstream from the stomach in the small intestine. If the stomach is not able to produce enough acid to bring the pH level of the chyme to an optimal range, after a while, the stomach will be forced to move it through the pyloric sphincter into the small intestine. Because it is not at the proper pH, the chyme does not trigger the release of sodium bicarbonate, which can result in duodenal ulcers. The higher pH of the chyme also does not trigger the release of pancreatic enzymes. The small intestine is not able to break down the chyme properly and the large, undigested particles of food can begin to have a negative impact on the lining of the small intestine. The lining becomes more permeable and allows the undigested food particles to enter the bloodstream where your body’s immune system recognizes them as foreign invaders. This triggers a systemic immune response that can lead to food sensitivities, inflammation, and autoimmune disease. This phenomenon is known as leaky gut syndrome.

Some undigested food particles may continue into the large intestine. This malabsorbed food can lead to a disruption of the normal gut flora (see this post for the importance of gut flora to health and the immune system). The large intestine may become inflamed and subject to a variety of conditions, such as constipation, diarrhea, or irritable bowel syndrome. The disruption of the normal gut flora also impacts your overall immune system and can lead to autoimmune conditions.

Prevalence and symptoms of low stomach acid

Low stomach acid is a common problem in developed nations. According to Jonathon Wright, MD (author of “Why Stomach Acid is Good for You“), approximately 90% of Americans produce too little stomach acid. He arrived at this conclusion after measuring the stomach pH of thousands of patients in his clinic. (While conventional medical doctors sometimes measure esophageal pH levels in particularly difficult cases of acid reflux, they never measure stomach pH levels. As mentioned above, any amount of acid in the esophagus is abnormal and will cause symptoms.)

Because low stomach acid has such a profound impact on overall health, symptoms may affect a variety of body systems and result in conditions that include:

  • Heartburn
  • GERD
  • Indigestion and bloating
  • Burping or gas after meals
  • Excessive fullness or discomfort after meals
  • Constipation and/or diarrhea
  • Chronic intestinal infections
  • Undigested food in stools
  • Food allergies, intolerances, and sensitivities
  • Acne
  • Chronic fatigue
  • Mineral and nutrient deficiencies (including iron and/or vitamin B12 deficiency)
  • Dry skin or hair
  • Weak or cracked nails
  • Asthma
  • Depression
  • Osteoporosis
  • Any autoimmune disease diagnosis

Hopefully, by now, it should be clear that covering up symptoms of heartburn, indigestion, and acid reflux by lowering stomach acid production even more through the use of acid-suppressing drugs, is not an effective, safe, or smart way to address the root cause of low stomach acid.

In part II of this series, I will discuss how to address low stomach acid holistically through the healing power of real foods and natural supplements. Stay tuned!



Wright, J. & Lenard, L. (2001). Why Stomach Acid is Good for You: Natural Relief from Heartburn, Indigestion, Reflux, and GERD. Lanham, Maryland: The Rowman & Littlefield Publishing Group.

  • Mary Ballerin

    I have alkaline reflux. I’ve been taking Tums for 14 months as a calcium replacement after a thyroidectomy and resultant hypoparathyroidism – I feel I was already low acid for several years before this. So, I quit the Calcitriol and Tums the other day because I feel sooo ill but I don’t know how to heal this alkaline stomach. I can numb it with lidocaine or take pain meds but relief only lasts 60-90 minutes. I have a bad gall bladder but the symptoms are similar. It’s been a long week.

  • Bridget Wilkin

    Why do “90% of Americans” produce too little gastric acid? How do we know what the correct amount is?

    • because a large percentage of the typical American diet is made up of processed and refined foods which do not contain the enzymes that are found within whole fools such as fruits and vegetables. When you eat, it’s those enzymes within the food, combined with some that your body creates whilst chewing that tell your body to begin producing hydrochloric acid (HCI).

    • James Beat

      A few million years of evolution, and 90% of Americans are producing too little stomach acid?
      Nature does not make mistakes like that, or we would all be extinct.

      Just like stomach acid burning holes through wood, this 90% figure is absolute nonsense.

  • Kyle Foresman

    I have a fairly consistent, yet mild, burning in my esophagus. I was given prescription zantac and take other things but nothing seems to help. It seems to come and go and I can’t match the symptoms with anything specific. Its been going on for about 45 days. Could burning/discomfort in the esophagus be related to low acid? Its very irritating. It almost seems less after I eat sometimes. Thx for any info!

  • Christian Hoogheem

    While this article provides some correct information, there is one thing in particular that really makes me irate as a chemistry teacher to the point where I just stopped reading. A pH of 1.5-3.0 is not strong, nor will it burn a hole in wood (take a look at Coke or Pepsi, they both have pHs around 2.5-3 and they aren’t burning holes in wood). pH is a determination of the concentration (amount) of H+. The more H+ there is, the lower the pH value. A strong acid is one that completely ionizes while a weak acid is one that only partially ionizes. It is very possible to have a weak acid that has an extremely low pH because of the high concentration of H+ ions. pH levels do not determine if something will burn a hole in something else; the identity of the acid will though.

    • James Beat

      Beat me to it.
      Also, it’s difficult to accept medical advice from someone who doesn’t know the difference between an alkali and an alkaloid!

      Rather than blaming the drug companies and medical professionals for ‘keeping us sick’, something really should be done about quacks posting stuff like this on the internet.
      I’m sure it’s meant well, but spouting this kind of nonsense without any medical training is extremely unethical, and should be illegal.

      Some of the information is accurate, but the problem is that it is being relayed by someone who doesn’t know what they are doing.
      A little knowledge can sometimes be more dangerous than no knowledge at all.

  • Billygoat

    I took Prilosec for several years thinking I had high stomach acid because of acid reflux I suffered. After learning that it might be due to low stomach acid I started taking a few spoonfuls of apple cider vinegar daily. After about a month my reflux was completely gone. ACV, unpasteirized, unfiltered is a miracle drug!

    • Peter

      Could you list the frequency and quantity of ACV eg before or after meals and
      whether tea spoon or table spoon. It’s a very similar story having been put on Losec five years ago for the same reasons inow have to stop medication for 2 weeks before my Endoscophy and finding it difficult and determined now to give it up after reading your story.

  • Billygoat

    Try apple cider vinegar

  • Rebeca Peres

    I do not know if the person that wrote this article is a doctor or not ,all I can say is that all I have read is true and correct.I am 40 and I was diagnose with Chronic Gastritis since I was 13 years old ,I had many duodenal and peptic ulcers along the way with lots of heartburn episodes that come and go along with multiple infections with Helicobacter Pilory, Campilobacter pilory, Giardi Lamblia, etc and have always had “LOW STOMACH ACID” also known as Hypochlorydria. It has been very difficult for me to find a reliable gastroenterologist for the simple reason that lots of them become doctors not because they love to help people to get better but to make lots of money like in a factory.Pharmaceutical companies are constantly sending their representatives to the doctor offices offering incentives and kick backs to them in exchange of prescribing their drugs those companies enjoy the outrageous profit margins only here in the US .The quality of healthcare in America has plunge while the price of it have soared to ridiculous levels ,just to put you in perspective I recently experience a heartburn episode so severe that I thought it was a heart attack in progress they did a blood test , two chest X rays and an ECG and the doctor saw me for 5 minutes the total bill came for $4000 can you believe it, come on ,the tests they performed on me do not cost more that $400 in materials and workmanship and the most expensive specialist I have gone charged me $350 ,so doctor fees ,personel ,hospital and tests should have been under $1000 . RIDICULOUS.

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