Why stomach acid is so important to your health

Stomach acid, gastric acid, hydrochloric acid – these all refer to the acid that is naturally produced by the cells lining the stomach. Too frequently, stomach acid tends to get bad press as it is considered to be the cause of many digestive symptoms; and consequently, medications that suppress its secretion are prescribed by the medical profession.


This article demonstrates why we need stomach acid, why very often you may have too little rather than too much, the very important roles it plays towards our health, and what you can do to support its levels.

What does stomach acid do?

The stomach is positioned quite high up in the thoracic cavity, towards the left-hand side, under the breastbone and above the navel.

It acts as a reservoir for food where predominantly protein digestion commences.

The higher the concentration of protein in the meal, the longer food will reside there - up to three hours for more dense protein foods such as a steak – and this is to support the efficient breakdown of the protein in the meal.

During the cephalic stage (based on the sight, smell and taste of food) followed by the chewing action in the mouth which triggers the release of more saliva, approx. 30% of gastric secretions are released into the stomach. The vast majority of gastric secretions occur once the food arrives in the stomach and causes its distension. The greater the protein content, the greater the release of gastric juice.

Stomach acid's important roles for our health

The stomach is intended to be highly acidic for several very important reasons:

1. The acidity neutralises harmful pathogens like yeast and bacteria that enter the body in food. If these are not destroyed, they may potentially cause food poisoning or upset the delicate balance of gut bacteria; and this in itself can have a whole host of further digestive ramifications such as diarrhoea, gas, bloating and pain.

2. The acidity activates the protein-digesting enzyme (pepsin) in the stomach which is required alongside hydrochloric acid to commence the splitting apart of protein molecules. The acid unravels proteins to enable the pepsin enzyme to get to work. Food is churned and mixed with the acid turning it into a type of gruel called “chyme” before moving onto the next stage of digestion in the small intestines.

If you can see undigested food in your stools (other than foods like sweetcorn), it can be a good indicator that digestive efficiency in your stomach is less than adequate as food should be unrecognizable once it leaves the stomach.

Woman eating burger

3. The acidic chyme triggers the release of further digestive secretions in the small intestines required for the complete breakdown of food for its absorption into the bloodstream. Really at this point, food is still external to the body and cannot be utilised, so to help optimise digestion and to support the absorption of the end products of digestion - simple sugars, amino acids and fatty acids and glycerol - we require good levels of stomach acid.

4. The acid helps liberate vitamin B12 from food and helps activate intrinsic factor required to enable B12 to be absorbed. Symptoms of B12 deficiency include memory loss, disorientation, hallucinations, and tingling in the arms and legs. [1]

5. The acid has an important role in the ionization of minerals like iron, zinc, calcium and magnesium for their effective absorption into the bloodstream. [2] Long-term, less than adequate levels of minerals can have far-reaching effects on bone health, red blood cell production, energy, to name but a few.

6. The acid helps to close the lower oesophageal sphincter which helps reduce the ability of the acid to pass back into the oesophagus which may lead to acid reflux.

7. The acid helps to activate the pyloric sphincter to enable 'chyme' to pass into the small intestines and therefore not remain in the stomach longer than necessary.

Acid reflux and potential triggers

The above is an impressive list of essential roles that are easy to overlook when one is faced with what appears to be an excess production of stomach acid.

Acid reflux (or GERD - gastro-oesophageal reflux disease) is an uncomfortable but very common symptom of heartburn. The oesophagus is not designed to experience acidic conditions so it only takes the smallest amount of acid for it to create discomfort to its delicate lining.

But why should acid leak back into the oesophagus? Other than more complex medical reasons such as hernia, one reason mentioned above is in relation to a lack of stomach acid not efficiently closing the sphincter muscle.

Other factors that may cause a little acid to pass back upwards is due to increased abdominal pressure. Two potential reasons for this are due to poor digestion of protein foods in the stomach leading to fermentation in the stomach creating gas; and/or an overgrowth of bacteria in the small intestines coupled with poor digestion of carbohydrates which may create excess gas.

As we can see above, these may all be a result of a lack of stomach acid in the first place.

GERD and acid reflux tend to increase with age yet naturally, stomach acid production decline. It is rare to see young people requiring acid suppressant medication.

Research carried out by Jonathan Wright, MD of Tahoma Clinic, Washington, has found that in 90% of over 40s with GERD or heartburn, stomach acid levels are low.

What factors contribute to low levels of stomach acid?

  • As we age the release of stomach acid secretions starts to reduce. [3]
  • Nutrients like B12, other B vitamins, magnesium and zinc (absorption may be hindered with a lack of stomach acid) are required to make stomach acid.
  • The long-term use of acid-reducing medication such as antacids and proton pump inhibitors.
  • Stress, especially chronic stress plays an important part as it naturally tells the body to favour the 'fight or flight' reaction taking attention away from digestion; the opposite para-sympathetic phase is known as 'rest and digest'.

Family mealtime

How to support stomach acidity?

  • The first simple steps are to focus on mindful eating. Always try to eat in as a relaxed a state as possible. Try to take yourself away from any stressful environment, such as away from your desk at work.
  • Try to avoid starting a meal without preparing your body to receive it. Some deep abdominal breathing can help to switch the body into its parasympathetic 'rest and digest' phase; go for a short walk at lunchtime (when at work) trying to distract yourself from your work activities.
  • Take time to eat your meal, thinking about the sight, taste and smell of the food; eat slowly, with small mouthfuls chewing food really well.
  • Only consume a small (200ml) glass of water with a meal to avoid over-diluting gastric secretions.
  • Avoid consuming tea and coffee close to mealtimes as this can interfere with digestive secretions.

Very often the symptoms of GERD, acid reflux, bloating, indigestion and excess burping tend to reduce or even disappear, subject to clients obtaining agreement from their GP to stop taking their acid-reducing medication. But this is managed in a controlled environment and should not be conducted without the appropriate support.

A simple bicarbonate of soda test can be a useful way to help a practitioner decide on the next steps. Taking a tsp of lemon juice in a tsp of water immediately before the start of each main meal can help to provide a more acidic environment and reduce symptoms.

Beyond this, a supplement of Betaine HCl can be very helpful but again, these recommendations should only be conducted with the support of a knowledgeable practitioner.

[1] https://www.hsph.harvard.edu/nutritionsource/vitamins/vitamin-b/#1 

[2] https://www.ncbi.nlm.nih.gov/pubmed/20882439 

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2920201/ 

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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Swindon SN1 & Cirencester GL7
Written by Caroline Peyton, Gut and Digestive Health Nutritionist and Naturopath
Swindon SN1 & Cirencester GL7

Caroline Peyton is an experienced naturopath, nutritional therapist, iridologist and coach. With over 10 years in practice she has helped countless clients with a multitude of digestive symptoms; and for many other health concerns, very often the root of the problem starts in the gut. Caroline is a passionate advocate of "health begins in the gut".

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