Low stomach acid

Stomach acid or hydrochloric acid is essential for the digestion of foods including proteins, protection against ingested pathogens and the absorption of nutrients. The production of stomach acid requires a lot of energy and is usually around pH 1.5-3.

Pepsinogen which is made by cells in the stomach is converted to pepsin by stomach acid and aids in the breakdown of protein foods into amino acids that can be absorbed by the body. It is stomach acid that signals for food to be moved into the small intestine so without it, food stays in the stomach and ferments causing gas and bloating. 

When food that hasn’t been broken down into small enough molecules reaches the small intestine, it is not able to be absorbed causing nutrients deficiencies and the unexpectedly large molecules may trigger an immune response, increasing the risk of food allergies or sensitivities. These large food molecules can also damage the gut lining causing leaky gut and bacteria are then able to escape out of the intestines and may cause an autoimmune response.

The stomach should be so acidic that it is able to kill off microbes and pathogenic bacteria and protect us against fungal and yeast infections.

Heartburn is often associated with increased stomach acid when in fact there isn’t enough. Undigested molecules of food sit in the stomach and ferment causing gas and burping which can feel like there’s too much acid. Antacids help by neutralising the gas but they are not addressing the root cause and used long term can make things worse.


  • Bloating, burping or gas shortly after eating.
  • Excess fullness after regular meals.
  • Wanting to eat even when not hungry.
  • Nausea when taking vitamins and supplements.
  • Heartburn or acid reflux.
  • Weak, brittle fingernails.
  • Loss of taste for meat.
  • Undigested food in stool.

If left untreated, low stomach acid can lead to mineral deficiencies as stomach acid is needed for the absorption of iron, calcium, magnesium, zinc, copper, selenium, boron and also Vitamin B12 and folate. This may result in anaemia, hair loss, chronic fatigue, mood imbalances such as anxiety and depression or skin conditions like acne, eczema, psoriasis or rosacea. Low stomach acid had also been shown to coexist with autoimmune conditions such as Hashimoto’s thyroiditis, rheumatoid arthritis, lupus and celiac disease. 


  • Stress.
  • Antacids.
  • Antibiotics and other medications.
  • Alcohol consumption or smoking. 
  • Nutrient deficiencies such as iron, zinc and B vitamins.
  • Age (65+).
  • Overeating, snacking, excess carbohydrates.
  • Eating disorders, extreme dieting, calorie restriction.
  • H. Pylori.
  • Stomach surgery such as a gastric bypass.

When we are stressed, our body is in fight or flight mode and our digestion shuts down meaning that digestive juices such as stomach acid and bile are not produced. The opposite state to this is rest and digest and this is the state we want to be in when we are eating so digestion is at its peak.

As we age, the production of stomach acid slows down and from the age of 65 onwards this can be a problem leading to nutrient deficiencies. Nutrient deficiencies can also be a cause of low stomach acid so it is a vicious cycle. Zinc and thiamine (B1) are both crucial in the production of stomach acid and alcohol depletes the body of thiamine.

Taking the time to get into a relaxed state before each meal and chewing each bite of food thoroughly, at least 20 times per bite, can help with the production of stomach acid.

Working with a nutritional therapist will help you to understand why you may have low stomach acid and what to do about it. 

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