The role of hydrochloric acid in protecting the body from disease

Includes the signs and symptoms associated with Iow gastric acidity.

By Sarah Swindlehurst-Mulliner, Raw Food Cleanse Coach & Yoga Therapist


Hydrochloric acid (HCL) is found and produced in the stomach. It is required to begin the breakdown of proteins into essential amino acids, and helps to kill any infections and bacteria (that could sometimes cause food poisoning), or yeasts. It also stimulates the pancreas and other organs such as the liver and gallbladder.

HCL is produced by the parietal cells in the stomach. The stomach has a ‘normal’ pH of 0.8-1.5 and is a million fold more concentrate than our body’s ideal pH of 7. [1]Due to the high acidic environment, the glands of the stomach also secrete large amounts of mucus to layer the stomach and protect the stomach lining from its own acid.

When we eat, our mouth produces the relevant enzymes to break down the food, starting in the mouth. The production of the relevant enzymes such as amylase and small amount of lingual lipase in the mouth send signals to the stomach in order to produce the correct amount of HCL and more enzymes (in the stomach) to further break down the foods when they reach it.  Sometimes a person might have too much gastric acidity and others low acidity (which I will discuss later)

The hydrochloric acid in the stomach is very important in the digestion process. Combined with the production of the inactive pro-enzyme pepsinogen (a major pro-enzyme of the gastric juice) which when activated by the HCL into its active enzyme form called pepsin, helps to break down tough/concentrated proteins such as meat and/or nuts. Undigested proteins (due to not chewing the foods fully, or low acidity in the stomach) could cause intestinal putrefaction into the intestines). Also of note is that the incomplete digestion of carbohydrates (fermentation autointoxication)[2]which can often lead to the production of gas, wind, bloating, and alcohols [3]and is rather destructive to the body. That said, should the stomach have a high acidity, or a high mobility of the stomach muscles causing the foods to pass through the stomach too quickly without being fully digested, can also cause this autointoxication [4] (fermentation symptoms can be due to low HCl both because food stays longer in the stomach, and also because low acidity favours an overgrowth of bacteria and yeasts).

However, HCL is extremely important in the prevention of disease also because it kills many microorganisms or bacteria that have been ingested by other means (bacteria on our fingers/hands, on the skin, etc). HCL is our health’s ‘first line of defence’ [3]as it stops infection/dis-ease/toxins going any further into our system. Should we have an inadequate amount of HCL then this can result in not digesting our foods fully (and autointoxication), but also not killing the germs and toxicity too.

There are many signs to look for which can indicate a low HCL level, such of which are; a bloating feeling, indigestion, burping, gas, and wind, all possibly due to the fermentation of foods in the stomach caused by an overgrowth of bacteria and yeasts. There can be a feeling of fullness due to the foods not being broken down fully in the stomach because of the low HCL production, resulting in foods sitting in the stomach for longer.  Undigested foods might be seen in stools as they come out without being fully digested. Multiple food allergies can be an indicator of low HCL also, which are predominantly caused by incompletely digested large molecules getting into the blood stream due a ‘leaky gut’. Leaky gut also can develop because of inflammation of the lining of the gut, resulting from an overgrowth of bacteria and yeasts. Iron deficiency is another indication of low HCL, due to the mineral (like magnesium and zinc – as all need HCl to be ionized, before they can be absorbed) not being released from the foods in the stomach (see osteoporosis below) and absorbed in the intestines. Other indictors include Candida infections (see below), heartburn, reflux, rectal itching, nausea, diarrhoea, constipation. 

There can also be a few crossovers in the symptoms for low acid levels with high acid levels, such as reflux, heartburn, and this can cause a person or Doctor to prescribe antacids and acid-blocking drugs for what they think is hyperacidity, but is actually low acid levels.


Here are some of the illnesses/diseases that can stem from low acid levels:

Indigestion: Can be caused by not chewing the foods probably, but also if there are low acid levels the foods are not digested properly and will ferment in the stomach and upper intestine, producing hydrogen, carbon dioxide and organic acids. This can also be a cause of excessive gas or belching/burping.

Osteoporosis: Low acid levels means that the body is not absorbing all the vital nutrients from the foods. Even if a person was consuming/supplementing plenty of calcium, zinc, magnesium and iron, if there is not enough HCL to ionise them, they will not be absorbed in the body, thus causing osteoporosis – a low bone density (regarding osteoporosis – calcium, and to a lesser extent magnesium, are most relevant here).

Diabetes: A lack of a HCL in the stomach will affect the other organs production, such as when the hormone secretin is released in the small intestine when the chyme enters it, which in turn then stimulates the pancreas to release insulin (and stimulates the gallbladder also). If HCL is low, then the pancreas will fail to produce adequate insulin to control the blood sugar – possibly resulting in diabetes.

Eczema: Can be a result of low HCL as irritation of foods having not fully been broken down, can be a reactive cause for allergies, resulting in the symptom of eczema and showing itself on the skin.

Gallbladder disease: When we eat a meal, especially one that containing fats, the liver and gallbladder are stimulated to release bile. The gallbladder concentrates the bile in between meals. Should a person have a low HCL then this would result in the liver not functioning fully and secreting enough bile, so then the gallbladder would not be ‘informed’ correctly to fully concentrate the bile in order to emulsify the fats, cholesterol, fat-soluble vitamins and break them down into small globules. This then would result in gallstones, and if left, could irritate the gallbladder, inflaming it, causing gallbladder disease. [5]

Psoriasis: Can be caused by incomplete digestion of proteins or poorly absorbed proteins. Instead of protein being broken down in the ‘usual’ way, bacteria will break the protein down and produce toxins, such as polyamines which block the production of cyclic AMP and contribute to psoriasis. [6]

Hepatitis E: Low HCL production can result in bacteria’s and poisons not being destroyed in the acid. Contaminated water or food being consumed can be the cause of this type of hepatitis. [7] (and many other infectious diseases)

Depression: A low HCL would mean that all the nutrients, vitamins and minerals would not be fully digested due to the foods not being broken down enough. Vitamin B6 is known as the ‘depression’ vitamin, and so if this is not absorbed from the foods then depression can result. (NB: neurotransmitters are built from amino-acids, a lack of proper protein digestion will also influence these)

Candida: A fungal infection belonging to the yeast family. It can colonise in the digestive tract and produce powerful toxins. HCL helps to destroy bacteria’s and yeasts, and so if they are not destroyed in the gastric acid, the yeast in the stomach will interfere with digestion of food and can be one of the causes of fermentation. The yeasts will then pass into the intestines and result in Candida.

B12 deficiency: Intrinsic factor is also secreted by parietal cells in the stomach. It is important for binding to vitamin B12. When it leaves the stomach, intrinsic factor helps B12 to be absorbed. A low HCL would mean vitamin B12 is not released from proteins, and cannot bind to intrinsic factor resulting in a deficiency of B12. (NB: it has been shown that HCl does not influence the secretion of intrinsic factor, but it is necessary to release B12 from proteins). Plus, a lack of B12 or of iron can lead to anaemias. [8] [9]


There are several methods of how to test a person’s acid level, such as taking a Heidelberg test[10],doing a self-test at home with some bicarbonate soda, various laboratory tests to reveal a deficiency in minerals and vitamins, and also testing yourself using some hydrochloride tablets plus enzymes. Once a person has discovered what their acid levels are then changes in that person’s diet and/or lifestyle can occur.

Method 1) For Home testing: Test to see if your HCL is low. Mix 1/4 tsp. of baking soda in an 8 oz. glass of cold water. Drink the baking soda and water mixture first thing in the morning before eating or drinking anything. Time how long it takes to belch after drinking the mixture. You should belch within 2 to 3 minutes if your HCL is adequate.

Method 2) For Home testing: Purchase supplemental HCL tablets from a health food or nutrition store. Take one 10 grain HCL capsule at the beginning of a substantial meal with protein. Take two capsules at the beginning of the next meal. Continue adding a capsule at each meal until you feel a burning sensation in your chest. Note how many capsules you took before you felt the irritation and inform your physician. Generally, the higher the number of capsules you take, the lower your HCL is.

Overall, it is a good idea to check the HCL of the stomach, especially if a person is showing signs and symptoms of having too higher acid levels or too low acid levels. All foods are processed via the digestive system, and broken down in the stomach. If a person has a healthy HCL level and are chewing their foods fully, then they will be absorbing the fully vitamin and mineral content of the foods they eat (NB: the small intestine is the main site of absorption, so if there is a problem there instead of with HCl content, absorption can still be impaired). If a person is fully digesting their foods (hopefully these are ‘healthy’ foods too), then they will have digestive wellness and a healthy body, and in turn a healthy mind too.

In addition: In general, a lack of HCl will affect the body in its entirety, as all our body systems need protein – e.g. the enzymes that we need for digestion are made of protein, the neurotransmitters are also mostly dependent on dietary protein (so a lack of properly broken down and absorbed protein (in the form of amino-acids) can lead to problems ranging from poor ability to cope with stress to more serious mental health issues etc.





[1] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.32

[2] Autointoxication; or, Intestinal toxaemia, John Harvey Kellogg. 1918. P.56-57

[3] NNT Stage 1, Module 1. Page 14


[5] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.261-263

[6] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.390

[7] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.336


[9] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.33

[10] Digestive Wellness, Elizabeth Lipski, 4th Edition. P.125