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:

Chronic stress

Aging

Poor diet

Infections

Medication use

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.