Adapted from episode 134 of The Perfect Stool podcast with Lindsey Parsons, EdD, and edited for readability.
Hypochlorhydria is the official term for a deficiency of stomach acid, which is hydrochloric acid (abbreviated HCI). If you don’t have enough stomach acid, you can’t digest food properly or absorb nutrients, because hydrochloric acid is essential for prompting the conversion of pepsinogen, released by the stomach cells, into pepsin, which breaks protein into peptides, composed of amino acids, as well as prompting the release of bile and pancreatic enzymes, which further aid in digestion. Amino acids are vitally important to all aspects of health, from building tissues to creating enzymes, which catalyze literally trillions of reactions in the body every minute, to creating antibodies, hormones and neurotransmitters and nitric oxide, which keeps the blood vessels open and blood flowing, to creating, storing and transporting energy. Amino acids also assist in buffering pH and maintaining the acid-base balance in the blood. I can’t actually overemphasize the importance of amino acids and protein in the body. Without an adequate supply, or if just one amino acid is in short supply and therefore you are missing one of the amino acids that is necessary to form a protein, of which there are 20, then you will not form a protein and your body will not perform some essential function. So if your body is slowly breaking down in a variety of ways, one of the first things to consider is a protein deficiency, which may have at its root a deficiency in stomach acid.
You may have also heard of essential amino acids. There are 9 of those: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine, which are considered essential because our bodies can’t make them and we must obtain them through our diet. If you’re taking an amino acid supplement, it should have 9 amino acids on the label. Many leave out histidine, I assume because it’s the precursor to histamine and many people with gut issues have histamine issues, but if you don’t, then you should make sure any amino acid supplement you take has all 9 essential amino acids.
Anyway, back to other symptoms of low stomach acid, which include indigestion, bloating, burping, nausea, heartburn, diarrhea, constipation, sulfur-smelling gas, feeling full quickly, undigested food in the stool, bad breath, nutrient deficiencies like B12 or iron, brittle nails, hair thinning, Candida and frequent infections, including SIBO or small intestine bacterial overgrowth and other bacterial infections or foodborne illnesses, due to stomach acid’s role in killing pathogens. I’ll also often see low amino acid levels on clients who have inadequate stomach acids, if we run a Metabolomix+ test*, which includes both an Organix brand Organic Acids Test and urine amino acids.
To understand stomach acid levels a bit, you should know that normal gastric pH while fasting is supposed to be under 3.0. While digesting food, you should have a pH of 1.5-3.5, but at least 2 or below some of the time as that acidity activates the enzyme pepsin, which breaks down proteins into peptides. Having a fasting pH above 7 is considered achlorhydria, or the complete absence of stomach acid, and if you take proton pump inhibitors (PPIs), you’ll have a fasting pH between 5 and 7.
You may have heard that aging is one cause of low stomach acid, and it would appear it is. Two (first study; second study) of the few studies on this question that went into some depth showed that while fasting, 89% of subjects with a mean age of 71 still had a low fasting stomach pH, but it was in re-acidifying the stomach after a meal that the differences showed through, compared to a group of subjects with an average age of 25. In the older subjects, it took an average of 89 minutes to re-acidify the stomach (defined as a pH of 2.0) after eating a meal, while it only took the younger subjects 42 minutes. And 16.4% of the older subjects took four hours to return to a pH of 2.0.
Oddly enough, low stomach acid can cause the same symptoms as too much stomach acid or hyperchlorhydria, that is, heartburn and GERD or gastroesophageal reflux disease. But typically, doctors will assume your symptoms are a result of too much stomach acid, if you have heartburn. They may diagnose you with GERD and prescribe proton pump inhibitors or PPIs. These medications can exacerbate the problem, preventing proper digestion of foods, nutrient deficiencies, in particular in vitamin B12, magnesium, calcium, iron and zinc, and when used long-term, can lead to bone fractures and osteoporosis, chronic kidney disease and dementia. So it’s vital to distinguish between too little and too much stomach acid. In order to avoid misdiagnosis – we can look to some other signs and side effects of hypochlorhydria.
First, one sign of hypochlorhydria is iron deficiency anemia. I’ve heard optimal ferritin levels quoted between 40 to 100 for women and 50 to 150 for men, or from another trusted source, 70 to 100 for everyone. But most people won’t get ferritin tested on routine blood work, so if you are below the reference range for RBC or red blood cells, Hemoglobin, Hematocrit, Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), or Mean Corpuscular Hemoglobin Concentration (MCHC) or are above the reference range for Red Cell Distribution Width (RDW), iron deficiency anemia is possible and you should ask your doctor for a full iron panel plus ferritin. And by the way, if you are deficient, I always recommend the iron bisglycinate form of iron for supplementation, as I took the cheap ferrous sulfate from the drugstore for years, and had to take two pills a day, that was 130 mg total, and I could never get my levels up. But a couple months on iron bisglycinate and I got levels back up into the standard reference ranges and easily kept them there – at only 25 mg a day. Not to mention that because it’s absorbed more easily, you’re less likely to have it eaten by any overgrown bacteria or have it contribute to SIBO, or have side effects like constipation. Also, you should take your iron ideally on an empty stomach with vitamin C for maximum absorption.
Another sign of low stomach acid is low B12 levels, which can be caused by pernicious anemia, which is when there is a lack of intrinsic factor, often due to autoimmune destruction of stomach cells called parietal cells, which produce intrinsic factor, which is necessary for absorbing B12. This leads to impaired B12 absorption, resulting in anemia. Of course there are other causes of B12 deficiency, the most common of which is a vegan or vegetarian diet, so don’t assume it’s pernicious anemia if you are on a vegan or vegetarian diet and are not supplementing with B12. Prior gastric surgery can also cause a lack of intrinsic factor, and of course our old friend, the bacteria which causes ulcers, Helicobacter pylori or H. pylori.
H pylori can be at the root of atrophic gastritis, or inflammation and thinning of the lining of the stomach, which is a precursor to pernicious anemia and to low stomach acid, as the parietal cells lining the stomach are responsible for producing hydrochloric acid as well. Again, you will not likely see B12 tested on standard blood work, but low RBC, Hemoglobin, Hematocrit or high MCV, MCHC or RDW are indicative of a possible B12 deficiency, which should prompt your doctor to test B12 levels. And while the reference ranges for B12 start in the 300’s, optimal levels are going to be above 700 pg/mL. Or even better, you could ask to get methylmalonic acid tested, which is an earlier and more accurate measure of low B12 and is found on Organic Acids Tests*, but can also be ordered by your doctor from standard blood testing labs. If you are deficient in B12, you are likely to have a stomach acid issue, in which case I always recommend sublingual B12 in the form of methylcobalamin, which is taken in a lozenge form that you let dissolve under your tongue so it directly enters the bloodstream. Typical dosages are 1000 mcg/day or 5000 mcg 1-2 times a week.
Hydrochloric acid also prompts the release of bile, which helps metabolize fat in the small intestine, so you can get fat maldigestion, when you’re low on stomach acid, which can lead to nutrient deficiencies, especially in the fat-soluble vitamins, which are D, E and A.
Other signs on a blood test of hypochlorhydria are low chloride levels under 100 (with 101 to 106 considered normal), which can be from a lack of chloride in the diet, which comes primarily from sodium chloride, aka salt. It can also come in smaller amounts from seafood, tomatoes, olives, lettuce and celery, but usually when someone is deficient in chloride, it’s usually because they eat a whole foods diet without much processed food and have taught themselves to eat little salt believing it to be a harmful nutrient. But it’s a goldilocks nutrient, with too little or too much being an issue, so if your chloride levels are low, you may need to salt your food more generously, take electrolytes daily or at least when you exercise, or even sprinkle some salt in your water.
Another sign of hypochlorhydria is abnormal serum protein levels, which would be if they are under 6.9 or over 7.4 g/dL or abnormal globulin levels under 2.4 or over 2.8 g/dL. This is especially in the case that your liver enzymes are relatively normal (that is your AST and ALT, which optimally should be between 18 and 25, but for the purposes of determining if they are relatively normal, just use the normal reference range on the test). Another possible sign of hypochlorhydria is low phosphorus levels with a vitamin D deficiency and/or hyperparathyroidism. Additionally, a high BUN level or blood urea nitrogen level of over 20 or more, indicating a high amount of nitrogen waste found in the bloodstream from poor digestion, can be indicative of low stomach acid. And finally, a low alkaline phosphatase level can be linked to low stomach acid and poor digestion.
Hypochlorhydria has also been postulated as one potential root cause of SIBO, or small intestinal bacterial overgrowth, according to studies on children taking PPIs. There may be a rise in pathogenic bacteria that are not killed off in an acidic stomach, such as certain pathogenic strains of E Coli, Clostridium, including Clostridium Difficile or C Diff, which you often see people getting after hospital stays and which causes explosive and frequent diarrhea, Enterococcus, including Enterococcus faecalis and faecium, Streptococcus, and overgrowths of yeast such as Candida albicans and Candida glabrata or other fungi, and/or other more pathogenic strains of H. Pylori. And taking PPIs has also been connected to SIBO, so it is clear that lowering stomach acid puts you at risk of SIBO. If you do have to take PPIs because of a condition like a hiatal hernia or a true case of high stomach acid, there is a probiotic that has been shown to prevent SIBO during PPI use, which I’d recommend alongside the PPIs, called L reuteri DSM 17938, which is found in both Biogaia Protectis Infant Drops* or Biogaia Gastrus* chewable probiotics. Nevermind that those are marketed to infants and children; the dosage is good for protecting adults too and I’ve heard great reports from several clients taking them.
So those are the main red flags and indicators of hypochlorhydria. Now let’s move on to the root causes of low stomach acid. It is widely accepted that an H. pylori infection is a common cause of hypochlorhydria. This is caused by the release of an enzyme from H. Pylori called urease, which breaks down in the stomach into carbon dioxide and ammonia, which neutralizes hydrochloric acid and causes burping and bad breath, in addition to the destruction of parietal cells from the bacteria burrowing into the lining of the stomach. However, in the early stages of an H. pylori infection, you can have high stomach acid and symptoms of gastritis, like burning in the stomach, particularly on an empty stomach.
Tests done by gastroenterologists for H. pylori are usually limited to urea breath tests, stool antigen tests and upper endoscopy exams, which usually include biopsies for H. pylori. Rarely, you might be offered an esophageal pH test or a Heidelberg Test to check if you have low or high stomach acid. I currently use stool tests like the US Biotek GI-Advanced Profile, which is my current favorite, or the GI Map to see if there is H. pylori and to see if it has virulence factors present, which indicate a risk for ulcers or stomach cancer. I only recommend treating it when levels are elevated, there are virulence factors or there are clear signs of issues as a result of it. Also, when you have a low stomach acid situation brought on by H. Pylori or other reasons, like aging, you will often see also low pancreatic elastase on a stool test, which is a digestive enzyme secreted by the pancreas. But it is worth mentioning that you may also see this decrease in pancreatic elastase for other reasons, such as gallstones or a vegetarian or vegan diet.
There are other possible root causes of hypochlorhydria, including autoimmune atrophic gastritis. I honestly haven’t heard much about this in the functional medicine community, but a few possible root causes of this autoimmune form of gastritis include H. pylori, as well as the other causes common to any autoimmune disease: genetic predisposition, a leaky gut, toxins from your food or environment and vitamin and nutrient deficiencies. It also commonly occurs along with other autoimmune diseases and is more common in older adults.
Chronic use of proton pump inhibitors may also result in hypochlorhydria, even after you’ve discontinued their use. And not surprisingly, acid-reducing medications like antacids and H2 receptor blockers can cause low stomach acid, which is probably why you would be taking them in the first place, but after you stop using them, there is no evidence that they cause ongoing hypochlorhydria. Some people do take H2 blockers for histamine issues as well, so that’s something to be aware of. Examples of H2 blockers are Pepcid, Tagamet, Zantac 360 and Axid, and examples of antacids are Tums, Rolaids, Milk of Magnesia, baking soda, Maalox, Mylanta and Alka-Seltzer. Acid-reducing medications, especially PPIs, are something to be particularly wary of because if you’re misdiagnosed with high stomach acid, doctors may prescribe you these very medications – only worsening your symptoms, if you do indeed have hypochlorhydria. For that reason, PPIs should only be used as treatment for a 14-day period. Examples of PPIs, some of which are over-the-counter in the US, some prescription, include Omeprazole, Prilosec, Zegerid, Nexium, Prevacid, Protonix, AcipHex, Dexilant, Losec, Zoton, Pantoloc, Somac, Pariet, Rabeprazole, Pantoprazole, Lansoprazole, Esomeprazole and Ilaprazole.
So in terms of correcting low stomach acid, I have been educating my clients on the Betaine HCl challenge for a few years now. I based that on the work of Sarah Ballantyne in her book The Paleo Approach,* which is an exhaustive and incredibly well-researched book on autoimmune disease and the Autoimmune Paleo diet. I have since heard criticisms that this approach to supplementing with Betaine HCl has no science behind it. So one of the reasons I wanted to do the episode was to have the time to research this question. What I found was a 2020 study on using Betaine HCl for re-acidifying the gut. They used PPIs to raise the pH in subjects’ stomachs, and once the pH was above 4.0 for 15 minutes, they gave them 1,500 mg of betaine HCl. They found that the average gastric pH in all subjects dropped from an average of 5.2 in the half an hour prior to ingestion to 0.6 a half an hour after supplementation. On average, it only took 6.25 minutes for the pH in the stomach to get under 3.0, and the re-acidification lasted on average 73 minutes, with a pH of 3 hitting at 73 minutes and a pH of 4 at 77 minutes, with a good amount of individual differences of up to 30 minutes for that rebound effect. Note that all of this was while fasting.
In another study using the design with pretreating with PPIs, they had subjects consume a light meal of only 336 calories, followed 5 minutes later by 1500 milligrams of Betaine HCl. In this case, it took an average of 67 minutes (plus or minus 33 minutes for the different subjects) to reach a pH of 0.838 (±0.391), which suggests it takes a lot longer to reacidify the stomach when you’re eating. Then it took an average of 76 minutes ±20 minutes to get back up to a pH of greater than 4, although the majority of the participants (5 of 8) didn’t even reach that within 3 hours.
The researchers from the first study suggest that dosages for Betaine HCl may need to be higher than 1500 mg to compensate for meals, and that taking Betaine HCl just prior to a meal may be a good idea for acidifying the stomach in advance. Of course, this is all assuming that you have some condition that is greatly reducing your stomach acid. It may be that a person who has low stomach acid doesn’t have as low stomach acid as someone who is on PPIs. So you have to take that into account.
So based now on this peer reviewed research paper, I’m more confident in recommending that if you suspect you have low stomach acid or hypochlorhydria, you may want to start with the Betaine HCl challenge. The way you would do that is to start with one capsule (which are sold in the 500-750 mg range) per full meal in the 500 calorie or greater range, only if the meal includes protein foods, then increase your dosage by 1 capsule/meal every 2 days. So if after taking it for the first time or at any point in the protocol, you feel a tingling, burning in your stomach, heartburn, diarrhea, unease, digestive discomfort, neck ache, backache, headache or any odd symptom, then it may be you have sufficient stomach acid or perhaps a hiatal hernia or some other issue. You can take an antacid or a teaspoon of baking soda in water or milk to neutralize the acid if it’s bothering you. If you were already doing well on a previous dose, you can decrease to the previously tolerated dose of Betaine HCl. You can go up to as much as 4-5 capsules, or 3000 mg maximum. If you’re trying to reduce the number of pills you take, I have only actually found one Betaine HCl that has 750 mg per pill and that’s the Designs for Health* one , which also has pepsin in it, which is recommended too. However, I often recommend the Vital Nutrients* one with Gentian Bitters for people who seem to have bile-related issues and obvious problems digesting fat, either based on their own experience or on seeing elevated fecal fats or steatocrit on a stool test. And do note that Betaine HCl is different than plain Betaine, also known as trimethylglycine or TMG, which is used as a methyl donor. And I’ll link to the study that outlines this suggested protocol in the show notes. If you scroll down, there’s a gray box with the protocol. But based on what I’ve read in this study, I think it is probably best to start the Betaine HCl 5 minutes prior to eating, and then periodically dose the additional pills as you’re eating.
Also note that there are some contraindications for using Betaine HCl, which include Barrett’s esophagus, diagnosed malformation of the lower esophageal sphincter, a history of stomach ulcers, any diagnosed disease or pathology of the pancreas, or if you’re taking NSAIDs, like Aspirin, or Tylenol, or Ibuprofen or have a diagnosed blood-clotting disorder. One alternative to taking Betaine HCl is to have 1-2 tbsp. of apple cider vinegar or lemon juice mixed in water 10-15 minutes before meals. And it’s super important to dilute that vinegar, because it can erode your tooth enamel, and some people even suggest drinking it through a straw. But again, if you have a diagnosis of Barrett’s esophagus, esophageal strictures or reflux esophagitis, you shouldn’t use these either, and of course, none of these things should be used if you an ulcer or a suspected ulcer.
So if you’ve determined you have hypochlorhydria, I’d suggest supplementing for a while as you work on other gut health issues, stress management and reduction, good sleep, adequate nutrition and supplementation of identified deficiencies, and adequate salt intake. If you have retested and determined that all these other things are in order and there are no more signs of low stomach acid on your blood tests, then it may be time to start reducing the Betaine HCl and see how you do.
If you’re still having issues or the blood numbers still indicate low stomach acid and you have H. pylori present in your gut, but at normal levels, then it may be time to try to eliminate or severely reduce the H. pylori to see if that’s what’s causing your low stomach acid. However, be aware that many gut health practitioners caution against eliminating H. pylori, as some people end up with acid reflux after eliminating it, which is one of the topics discussed in Martin Blaser’s classic book Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues*, in which he describes his life’s work studying H. pylori. So maybe if you have low stomach acid and no H. pylori you should find someone to kiss who has H. pylori and get some back, as it’s transferred via saliva. People have certainly done crazier things to help their gut health! But I’m just kidding. In my experience, herbal antimicrobials, as opposed to triple or quadruple therapy using antibiotics and PPIs, tend to reduce but not eliminate H. pylori. Mastic gum* is the primary one used for that purpose, but other antimicrobial agents like berberine and hydrosol silver*, as well as mucilaginous agents like marshmallow root, DGL, slippery elm, aloe* and okra are also useful in healing the gut lining.
So if you’re dealing with low stomach acid or gut health issues of any type and need some help, I see individual clients to help them resolve their digestive issues and you’re welcome to set up a free, 30-minute breakthrough session to see if you’d like to work with me. I also have my own two products, Tributyrin-Max, which is particularly helpful for loose stool and diarrhea as it slows your motility and firms up your stool, and SBI powder, which is an all around gut pathogen binder, which is super safe and won’t harm beneficial bacteria, and is usually the first line of treatment I educate my clients about in order to avoid stronger antimicrobial herbs.
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