Functional medicine practitioners often take a “Foods First” approach, recommending dietary modifications to improve health. However, for those with low stomach acid, diet alone may not be enough to ensure adequate nutrition. Low stomach acid can impair digestive ability, causing nutritional deficiencies even in those individuals consuming an optimal diet.
This article will focus on the main digestive chemical associated with the stomach, hydrochloric acid. The causes of low stomach acid and the associated symptoms will be covered. In addition, natural treatment options for low stomach acid, such as betaine HCL and herbal bitters will be discussed.
What is Digestion?
Digestion is the process of breaking food down into particles small enough so that the nutrients in the food can be absorbed and then transported throughout the body. Digestion begins in the mouth with the mechanical process of chewing along with salivary enzymes that begin the digestive process. This process is continued as the food passes into the stomach, activating the release of hydrochloric acid. The bolus of food then passes to the small intestines where the majority of digestion takes place. The useful nutrients are digested and absorbed and the waste products are sent through the large intestines for evacuation as feces.
Why Does the Stomach Contain Hydrochloric Acid?
The stomach is a naturally acidic environment, especially following a meal, with a normal pH value of <3. Low stomach acid (hypochlorhydria) is observed with a rise in pH >3 and an absence of stomach acid (achlorhydria) is obtained with a pH > 7.1 This acidity comes from the hydrochloric acid that is secreted by the parietal cells in the lining of the stomach.
Healthy stomach acid levels serve as an immune system barrier, providing a first line of defense against unwanted bacterial or microbial invaders that enter the stomach. Hydrochloric acid is also necessary for the digestion of proteins. Proteins are a conglomeration of amino acids folded together into different shapes.
Stomach acid serves to denature (unfold) the proteins and expose the bonds that hold the amino acids together. These bonds can then be cleaved by pepsin, which breaks the protein down into smaller, easier to digest, amino acids. The formation of pepsin from pepsinogen is dependent on sufficient stomach acid levels as well.
Hydrochloric acid is also responsible for deactivating the enzymes of salivary amylase as it enters the stomach and for stimulating the release of cholecystokinin in the small intestines. Both processes are essential for healthy digestive function. Certain vitamins and minerals depend on hydrochloric acid to liberate them from their carriers, such as vitamin B12 and calcium. Having low stomach acid levels can impair all of these functions.
What causes low stomach acid levels?
Factors that contribute to low stomach acid include:
Stress—Stress impairs digestion. Chronic stress may decrease the production of hydrochloric acid in the stomach due to associated nutrient deficiencies.2 Stress also causes the vagus nerve to lose its proper tone. The vagus nerve is a major part of the parasympathetic nervous system, and it is deeply involved in stomach acid production. With chronic stress it loses its ability to fire properly which disrupts normal stomach acid production.
Aging—Low levels of stomach acid following a meal are more common with aging. Studies that compared stomach acid levels in young individuals (mean age 25) versus older individuals (mean age 75) found that older individuals experienced low levels of stomach acid following a meal for a greater length of time than their younger counterparts. It took 89 minutes for the elderly participants versus 42 minutes for the younger participants to regain normal stomach acid levels (pH 3.0) following a “standard meal”.1, 3, 4 These studies help support the existence of “functional low stomach acid levels” in the elderly following meals.
Poor Diet—Eating a diet comprised of highly refined sugars and carbohydrates, alcohol, and/or smoking may result in nutritional deficiencies of B vitamins or zinc, both necessary for the production of hydrochloric acid in the stomach.
Infections—Healthy stomach acidity provides a barrier for the immune system’s first line of defense against invading substances. Low stomach acid results in an impaired immune response and an increased susceptibility to viral and/or bacterial infection and to bacterial/microbial overgrowth. Common conditions associated with low stomach acid include Helicobacter pylori, small intestinal bacterial overgrowth (SIBO), and Clostridium difficile.1
Medications—Medications, such as antacids, proton-pump inhibitors (PPIs), and H2-receptor antagonists (H2-RAs), are another widespread cause of low stomach acid. These medications are used to decrease the symptoms of gastroesophageal reflux disease (GERD) and peptic ulcer disease (PUD). Long-term use of these drugs has been associated with an increased risk of fracture due to nutrient deficiencies connected to low stomach acid. Approximately 25% of Americans may be using some form of acid reducing medication as the prevalence of GERD in North American has been estimated to be between 18.1% to 27.8%.5
Surgery—Gastric bypass surgery can reduce the production of stomach acid.
What are the symptoms of low stomach acid?
Burping, Bloating and Gas—An adequate level of stomach acid is necessary for the digestion of minerals and proteins into smaller amino acids that can be passed into the small intestines for further digestion and absorption. Low stomach acid can lead to undigested proteins being present in the stomach and being subsequently passed into the small intestines. These undigested particles are too large for absorption and create increased burping, bloating, and gas as they ferment. This increased gastrointestinal inflammation can set the stage for the development of intestinal permeability, commonly referred to as leaky gut.
Indigestion/Heartburn—Heartburn may occur when stomach acids leak up into the esophagus, causing burning. This displacement of stomach acid away from the stomach leaves low stomach acid levels in the stomach. If left untreated, this acid reflux can lead to conditions such as asthma and/or esophageal cancer.
Undigested food in stool—The undigested food particles may be passed through the digestive tract and expelled in feces. These can often be visible in the stool.
Food allergies and/or hypersensitivities—In the presence of intestinal permeability, the large, undigested protein particles can pass through the leaky intestinal membrane barrier. This activates the immune system into action as these large particles are targeted as invaders. The net result is the development of food allergies and/or hypersensitivities.
Stomach pain—Inflammation in the lining of the stomach (gastritis) can result in stomach pain. This is often due to a H. Pylori infection. Increased levels of gastrin are produced that destroy parietal and chief cells. This results in a decrease in stomach acid and can result in a loss of intrinsic factor, leading to a B12 anemia. There is an increased risk of gastric cancer if left untreated.
Avoidance of Meat—Many individuals will avoid eating meat due to their decreased ability to digest the proteins when stomach acid is low. They find they experience fewer digestive complaints when they do not eat meat.
Weak or Brittle Nails, Hair, Bones—The inability to digest proteins and certain minerals and vitamins, such as calcium, magnesium, iron, vitamins B6, B12, and folic acid, can be related to low stomach acid. These nutrients are necessary for the growth of healthy nails, hair, and bones. Common diseases that may develop include anemias, osteoporosis, and osteoarthritis.
Neurological issues—The nutritional deficiencies, particularly the B vitamin anemias and magnesium, can contribute to neurological issues such as numbness, tingling, and vision changes.
Diarrhea—Low levels of stomach acid increases the risk of gastroenteritis, diarrhea, and Clostridium difficile colitis.
Fatigue—Ongoing nutritional deficiencies, infections, and/or diarrhea can contribute to fatigue.
Betaine HCL and Herbal Bitters supplementation
Guilliams and Drake (2020) reviewed the practice of using Betaine HCL with meals as a treatment option for individuals with low stomach acid. In this review they discussed many of the issues that we have discussed associated with low stomach acid. They also reviewed research that supports methods to increase stomach acid easily. Two of the more practical methods included the use of plant extracts, commonly known as bitters, and the use of betaine HCL to temporarily increase acid levels with meals.1
Bitters promote digestion by stimulating the secretion of stomach acid, digestive enzymes, and bile. Original Bitters is a liquid herbal formula developed by David Winston that can be used for this purpose. It is recommended to take this mixture 10-15 minutes before meals to ensure adequate time for the digestive secretions to develop prior to food entering the system. They do suggest caution in those individuals with gastric ulcers, GERD, or gastritis. The use of bitters is not recommended in those with too much stomach acid.
Betaine HCL can replenish stomach acid levels, increase the body’s ability to digest proteins and minerals, and help decrease the symptoms associated with a deficiency. Moss Nutrition makes a Betaine HCL that supplies 750 mg of pure anhydrous betaine hydrochloride in an easy-to-swallow, vegetarian capsule. Use of this product can help decrease digestive distress and improve digestive function.
Betaine HCL works by easily donating its H+ ions in an aqueous environment, creating an acidic solution. Because of this, it is important to never chew supplements containing betaine HCL. The acid can easily corrode dental enamel or burn sensitive esophageal tissue. The stomach, with its protective mucus lining, is designed to handle the acidity. Supplements in tablet or capsule form that can be easily swallowed allow the betaine HCL to pass through to the stomach without damage to the more sensitive tissues along the way.
When shopping for a supplement to increase stomach acid levels make sure to purchase betaine HCL and not simply betaine. Both have biochemical value, but only betaine HCL contains the HCL necessary to increase low stomach acid levels. Betaine, aka. trimethylglycine, can be found in foods such as beets and choline rich foods. It serves as a methyl donor and is useful for proper liver function, cellular replication, and detoxification reactions.
Proper methylation is essential to many of the chemical processes in the body including biosynthesis of lipids, the regulation of several metabolic pathways, and liver detoxification. Other methyl donors include B12, folic acid, and zinc. Deficiencies in these vitamins due to low stomach acid increases the need for additional methyl donors such as betaine. Moss Nutrition’s Betaine HCL provides both of these necessary nutrients.
According to Shay et al., “The administration of pepsin with hydrochloric acid is not in our opinion essential” so there is no reason to use Betaine HCL products with added pepsin.
How is low stomach acid tested?
A common test used by Integrative and Functional Medicine practitioners for low stomach acid involves the use of gradually increasing doses of betaine HCL at sequential protein-containing meals. The dosage continues to increase until uncomfortable symptoms, such as heartburn, tingling, or diarrhea develop. Any discomfort noted is a signal that the necessary dose has been exceeded and the individual should decrease to the last tolerated dosage taken. The acid can be neutralized by drinking a mixture of 1 tsp baking soda in water or milk. Improvement in any of the clinical symptoms, such as a reduction in heartburn or increased ability to digest proteins are considered positive indicators that stomach acid was low. This test, though anecdotal, has been used successfully by many practitioners. Clinical research is needed to substantiate its validity.1
The Heidelberg pH diagnostic system is done by swallowing a radio-telemetric capsule which signals a machine what the pH is in the stomach. The Patient swallows sodium bicarbonate periodically and time to re-acidify the stomach is measured.
Gastric intubation, catheter electrodes, and pH-sensitive tablets are other methods utilized in research and clinical practice.
Guilliams and Drake (2020) recommended the use of betaine HCL with meals to increase stomach acid levels and improve digestive function. They reviewed current research that measured the ability of betaine HCL to increase stomach acid levels in individuals taking PPIs and thereby increase absorption of pH dependent drugs. Proton pump inhibitors work by decreasing stomach acid levels, on average to a pH of 5.2. Taking a betaine HCL supplement improved stomach acidity to a pH of <3 withing 6.25 minutes. The stomach acidification was temporary, with results lasting ~ 75 minutes. This research confirmed the safety and possible necessity of betaine HCL to increase stomach acid temporarily for individuals using PPIs and to increase solubility and absorption of pH dependent drugs.6, 7 A possible confounding factor in this research is that the study was conducted in the fasted state. Betaine HCL in a real-world setting would only be used during a fed state and the presence of food may alter the stomach acid pH dynamics.
A similar study by Faber et al. was conducted on individuals in a fed state to eliminate this possible bias. The betaine HCL lowered gastric pH just as in the prior study, but it took approximately 3 times longer to do so. This delayed response may be due to the ingestion of betaine HCL 10 minutes after the start of a meal. It was therefore recommended taking betaine HCL supplements just minutes before or at the start of a meal. They suggested that the dosage may also be divided throughout the meal to sustain the necessary pH levels for a greater length of time.8 These studies support the use of supplemental betaine HCL to increase stomach acid levels, even in those taking medications such as PPIs.
Low stomach acid can result in the following deficiencies:
Hashimoto’s Disease, Hypothyroidism, and Low Stomach Acid
Stomach acid can be low in Hashimoto’s disease due to hypothyroidism but also due to pernicious anemia(B12 deficiency) which is common in this disease. Iron deficiency is also common in these conditions which also causes low stomach acid. We also have to think about H. pylori infection in the stomach as a disruptor of normal stomach acid production. Autoimmune atrophic gastritis can happen along with Hashimoto’s disease which further drives stomach acid down. Small Intestinal Bacterial Overgrowth (SIBO) is also common in hypothyroidism which can disrupt stomach acid levels.
Betaine HCL supplementation can damage the stomach lining if taken by certain individuals so use extreme caution with this supplement and always be under the care of a qualified healthcare professional. Betaine HCL should definitely be avoided in pancreatitis and AIDS patients. Betaine HCL also has an acidotic effect on your body’s pH so be sure you’re monitoring your pH and countering the effects of metabolic acidosis with proper diet and supplement strategies.
Increasing stomach acid can have some powerful and even life-changing benefits if stomach acid levels are low. If you suspect you have low stomach acid, talk to your doctor about addressing this important and often overlooked aspect of ill health.
2. Inhibition of gastric acid secretion by stress: A protective reflex mediated by cerebral nitric oxide | PNAS. Accessed March 11, 2021. https://www.pnas.org/content/93/25/14839
3. Russell TL, Berardi RR, Barnett JL, et al. Upper gastrointestinal pH in seventy-nine healthy, elderly, North American men and women. Pharm Res. 1993;10(2):187-196. doi:10.1023/a:1018970323716
4. Dressman JB, Berardi RR, Dermentzoglou LC, et al. Upper gastrointestinal (GI) pH in young, healthy men and women. Pharm Res. 1990;7(7):756-761. doi:10.1023/a:1015827908309
5. Sandhu DS, Fass R. Current Trends in the Management of Gastroesophageal Reflux Disease. Gut Liver. 2018;12(1):7-16. doi:10.5009/gnl16615
6. Yago MAR, Frymoyer AR, Smelick GS, et al. Gastric Re-acidification with Betaine HCl in Healthy Volunteers with Rabeprazole-Induced Hypochlorhydria. Mol Pharm. 2013;10(11):4032-4037. doi:10.1021/mp4003738
7. Yago MR, Frymoyer A, Benet LZ, et al. The use of betaine HCl to enhance dasatinib absorption in healthy volunteers with rabeprazole-induced hypochlorhydria. AAPS J. 2014;16(6):1358-1365. doi:10.1208/s12248-014-9673-9
8. Faber KP, Wu H-F, Yago MR, et al. Meal Effects Confound Attempts to Counteract Rabeprazole-Induced Hypochlorhydria Decreases in Atazanavir Absorption. Pharm Res. 2017;34(3):619-628. doi:10.1007/s11095-016-2090-2