Why stomach acid is so important to your health

Stomach acid, gastric acid, hydrochloric acid - these all refer to the acid 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.

In this article, we'll explore 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, approximately 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.

7 reasons why stomach acid is essential for our health

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

1. Protects against pathogens

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. Activates protein-digesting enzymes

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.

3. Triggers further digestion

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. Supports vitamin B12 absorption

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

5. Aids mineral absorption

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

6. Prevents acid reflux

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. Regulates digestion timing

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.

Common causes of low stomach acid

Several factors can reduce stomach acid production:

• Ageing: As we age, the release of stomach acid secretions starts to reduce. Acid levels naturally decline after age 40.
• Nutritional deficiencies: Low levels of zinc, magnesium, and B vitamins can impair stomach acid production.
• Medications: Long-term use of acid-reducing drugs (antacids, proton pump inhibitors) can suppress stomach acid.
• Chronic stress: Stress diverts energy away from digestion, reducing stomach acid secretion.

Is acid reflux linked to low stomach acid?

Acid reflux (GERD) is often attributed to excessive stomach acid, but research 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. Without enough stomach acid to close the lower oesophageal sphincter, even small amounts of acid can leak into the oesophagus, causing discomfort.

Additional factors like bacterial overgrowth and poor digestion can increase gas and pressure, pushing acid upwards. Addressing the root cause - low stomach acid - may help alleviate these symptoms.

How to support healthy stomach acid levels

Making simple lifestyle changes can improve stomach acid production and overall digestion:

1. Practice mindful eating

The first simple step is to focus on mindful eating. Always try to eat in as 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.

2. Limit liquids around meals

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.

3. Try natural remedies

Taking a teaspoon of lemon juice or apple cider vinegar diluted in water immediately before the start of each main meal can help to provide a more acidic environment and reduce symptoms. A simple bicarbonate of soda test can help determine if low stomach acid is an issue.

4. Consult a practitioner

If natural remedies don’t improve symptoms, consult a healthcare provider about using Betaine HCl supplements. These should only be taken under professional supervision.

Stomach acid is more than just a digestive aid - it’s essential for nutrient absorption, gut health, and overall well-being. Many digestive issues, including acid reflux and bloating, may stem from low stomach acid rather than excess. By understanding the importance of stomach acid and adopting supportive habits, you can improve your digestion and long-term health.

If you suspect low stomach acid is affecting you, consult a qualified practitioner for personalised advice.