Altered Digestive Secretions
Our digestive secretions, which include gastric acid, pancreatic enzymes and bile are required for us to properly digest and assimilate food. These secretions also eradicate any pathogens we may have ingested. Any alterations in the production of these secretions may create digestive disturbances.
Gastric Acid (HCl)
Of all GI secretions, gastric acid is the most important. The cells that line the stomach wall secrete gastric acid and this is what initiates the digestion process, especially the digestion of proteins. Gastric acid converts the contents of our stomach into a semi-liquid mass called chyme, preparing it to be further digested in the small intestine.
Gastric acid performs many important functions, including:
- Breaking down proteins
- Stimulating your pancreas to produce the digestive enzymes necessary to further break down the carbohydrates, proteins and fats you eat.
- Killing harmful pathogens we may have ingested, such as food borne bacteria, which helps prevent infections taking hold in your gut. If you have low gastric acid, you have an increased susceptibility to infection with enteric pathogens.
- Creating an acidic environment, this is required for the absorption of certain micronutrients, such as calcium, magnesium, zinc, iron, and selenium.
Signs and symptoms that indicate you may not be producing enough gastric acid include:
- Bloating, belching, flatulence and a heavy feeling in your stomach after meals
- Heartburn and indigestion
- Diarrhea or constipation
- Undigested food in stools
- Iron deficiency anaemia
- Vitamin B12 deficiency
Researchers have also associated low levels of gastric acid with food allergies. Gastric digestion decreases the potential for proteins from food to bind with Immunoglobulin E (IgE). This increases the amount of allergens needed to elicit an allergic reaction. (1)
Studies have shown that patients on antacids, which block pepsinogen from converting to pepsin and therefore inhibit the digestion of protein, have a higher risk of allergic reactions to food. (2)
There are numerous causes of low stomach acid. The most common are:
- Helicobacter pylori infection – H. pylori suppresses the production of stomach acid.
- Stress – Chronic stress has been shown to decrease the production of stomach acid.
- Use of antacids such as Mylanta.
- Use of H2 Inhibitor medications such as Zantac
- Use of Proton Pump Inhibitor medications such as Nexium
- Age – Numerous studies have shown that our stomach secretes less acid as we age.
- Atrophic gastritis – A chronic inflammation of the stomach mucosa inhibits stomach acid.
- Hypothyroidism.
Pancreatic Enzymes
The pancreas secretes pancreatic enzymes into the small intestine, which breaks down proteins, fats and carbohydrates in preparation for absorption into the blood stream.
Symptoms of insufficient pancreatic enzymes include:
- Bloating or painful stomach cramps after meals
- Loose, greasy, foul-smelling stools
- Deficiency of fat-soluble vitamins A, D, E and K
- Diarrhea
Exocrine pancreatic insufficiency (EPI) is a condition that results when the pancreas doesn’t secrete enough digestive enzymes. Someone with EPI who doesn’t have enough pancreatic enzymes cannot properly digest the nutrients in foods such as protein, fats, and carbohydrates. In one study, EPI was found to exist in 6.1% of patients with IBS-D. (3)
Bile
Bile is a fluid produced by our liver that helps us digest fats in our small intestine. Bile actually emulsifies fat, increasing the absorption of fat into the bloodstream.
Bile acids are known as endogenous laxatives (endogenous meaning originating from within the body) because they trigger propulsive contractions in the bowel and bring water into the colon. (4)
In fact, a condition known as bile acid malabsorption (BAM) is known to cause chronic diarrhea. This condition is caused by excess bile salts entering the colon rather than being absorbed in the small intestine, increasing the reabsorption of water and colonic movement, which results in diarrhea.
Studies show that bile acid malabsorption (BAM) accounts for at least 30% of patients diagnosed with functional diarrhoea and IBS-D. (5)
Changes in the synthesis as well as the concentration of bile acids in the colon have also been identified in people with IBS-Constipation.
People with IBS-C have been found to have a decreased concentration of deconjugated bile acids compared to healthy people or people with IBS-D. (6, 7)
The reduction of the secondary bile acids in the colon leads to slower bowel movement and less water brought into the bowel, resulting in constipation.
One of the many functions performed by the bacteria in your gut is converting primary bile acids into secondary bile acids. These processes are called deconjugation and dehydroxylation. Specific strains of bacteria perform these functions and if their amounts or location are altered, as happens in intestinal dysbiosis or SIBO, then the conversion of primary bile acids to secondary acids will also be affected and altered, which can potentially lead to constipation and/or diarrhea.
The functions of digestive secretions are the cornerstone of optimal digestive health. Improving your digestive secretions is one of the most important steps in improving your digestion and lessening the symptoms of IBS.