In part I of this series on digestive health I covered the very first stage of digestion, which begins in the brain. Now the food has reached the stomach there are a number of processes and moving parts that will enable good downstream digestion.
Stage Two: The stomach
The stomach is a pillar of good digestive health. The stomach is host to a number of important functions including:
- chemical reactions that further breakdown food;
- nutrient extraction of proteins, vitamin B12, iron and some other vitamins and minerals;
- killing pathogens before they can enter the colon;
- transfer of food contents to the colon where a huge number of nutrients are absorbed; and
- acting as a repository for food – not everything we eat in one meal can be transported into the colon so quickly.
Stomach acid is key to healthy stomach function
Sadly today big pharmacy has convinced us the stomach acid is a bad thing, which is the rationale behind the billion dollar/pound antacid and proton pump inhibitor industry. All that these medicines do is suppress a very normal and important function of the body, which is to produce enough acid so that our food can be adequately broken down and transported through the body properly. I cover the problem with the current heartburn paradigm here.
The stomach contains 6 different types of cells that all secrete different substances, which facilitate digestion. When the contents of our chewed food (called bolus) enters the stomach, juices secreted from the millions of tiny cells located in the lining of the stomach.
These cells secrete a combination of:
- hydrochloric acid – an acidic substance that breaks down food;
- pepsin – digestive enzymes that breakdown protein and are formed from pepsinogen being converted in the presence of HCl;
- intrinsic factor – facilitates the absorption of vitamin B12
- mucous – to lubricate the lining of the stomach and prevent damage.
The stomach MUST be acidic
An important characteristic of the stomach is its low pH, meaning its very acidic environment. The stomach should maintain a pH of between 1.5 – 3 and sometimes this is even lower (more acidic) if we eat a lot of protein, which is tough to breakdown. The function of stomach acid is to break down food so it will not damage the intestine, and to ensure it is digested enough to release nutrients, which are absorbed through the slightly permeable lining of the small intestine.
Stomach acid kills bugs
If the stomach is not acidic enough it does not perform its function of killing pathogens and bacteria such as salmonella and cholera. This can lead to a host of infections and diseases. H-pylori and small intestinal bacterial overgrowth (SIBO) are bacterial infections that are common problems in people with low stomach acid. If allowed to grow out of control, these bacteria can “steal” our nutrition leading us to be deficient in certain minerals and vitamins and ultimately become very sick.
Stomach acid also facilitates proper absorption of important nutrients such as iron and vitamin B12. Stomach acid facilitates dissociation of nutrients from their carriers, meaning they are absorbable to our body. Without adequate amounts of nutrients that nourish our cells we can develop a host of conditions such as fatigue, brittle bones and nails and even memory loss. Stomach acid is supposed to be there and we should be doing what we can to support it, not supressing it with expensive drugs.
Other cells in the stomach also stimulate the muscles to churn and stir the contents of the stomach, which is called chyme. This ensures the chyme is adequately mixed and that the low pH (acid) is spread throughout to breakdown everything.
Impaired stomach function
There are a multitude of factors that serve to impair stomach acid production, meaning that it is likely that most people in a busy, stressful and processed food dominated Western world have low-stomach acid and impaired digestive function. A variety of medications, alcohol, coffee, not chewing properly, stress and many more common things serve to limit stomach acid production. This is not helped by the fact that the medical establishment understand heartburn to be the result of too much stomach acid and so prescribe antacids with fervour. It is a misinformed and irresponsible practice that likely has huge consequences including disease outbreaks and deep-seated nutrient deficiencies. I will delve deeper into this in a later post. However, I hope I have successfully conveyed to you the importance of an acidic stomach in the human digestive process.
Release from the stomach to the small intestine
The pH of the chyme in the stomach must be low enough that it triggers the release of the contents through the pyloric sphincter. The stomach contents then reaches the upper part of the small intestine, which is called the duodenum. This low pH not only allows the sphincter to open, but triggers the release of mucous, which serves to protect the small intestine.
In part III of this series on digestion we look at the important role of the pancreas, liver and gallbladder in digestion.