A great quote by my mentor Charles Poliquin is that, “it doesn’t matter what you ingest, it matters what you can assimilate.” What this refers to is that eating healthy and taking all the supplements in the world doesn’t make much of a difference if you are not able to properly digest them. In 101 we are going to discuss the role of the stomach in digestion.
The stomach basically has two major functions for digesting your food. It has a mechanical and a endo-chemical process. The endo-chemical part is the production of gastric juices that start to break down your food, kill microbes, and stimulates the later parts of digestion. The mechanical process is basically a way of swishing around your food in the stomach to break it up and expose all the food the the gastric juices.
Lets start at the beginning. When you eat, you are using almost all your senses to prepare your digestive system for the food in which it is about to receive. The smells, the taste, receptors on the mouth, tongue, and throat, the mechanical motion of chewing all work to signal your body that food is coming. Experiments have even shown that auditory signals like a dinner bell can begin the digestive process. The final message is actually a stretch reflex of the stomach which stimulates the medulla oblongata. The medulla then signals your body to release the hormone gastrin.
Gastrin is the hormone that tells your stomach to star releasing it’s gastric juices. The muscular walls of the stomach contract vigorously to mix food with gastric juice, producing a mixture called chyme. The majority of people with digestive issues have a problem with the gastric juices their stomach is creating. Most people are familiar with heart burn or acid reflux, which is sometimes caused by over active production of acid, but can also be caused by the sphincter between the stomach and the esophagus malfunctioning allowing the stomachs normal healthy acids to leak up into the esophagus.
Another cause of the heart burn or GERD sensations is alkaline reflux. Most people don’t realize that not having enough acidity in the stomach can cause the same and even worse problems than having too much. Also treating acid reflux and heart burn by buffering or stopping acid production can lead to long term health problems. Taking these kind of medications rather than healing the stomach and restoring proper function can result in the loss of digestive function. (see links at the end)
Gastric juices are made of 3 main components.
- A mucous that protects the stomach lining from the acid and digestive enzymes in the stomach.
- Pepsinogen, which is converted to pepsin, which digests proteins. Pepsinogen production is stimulated by the presence of gastrin in the blood.
- Hydrochloric acid (HCl) converts pepsinogen to pepsin which breaks down proteins to peptides. HCl maintains a pH in the stomach of approximately 2.0. It also dissolves food and kills microorganisms.
When a piece of meat was allowed placed in simulated gastric juices and heated to body temperature only the mixture containing full pepsin and HCl broke down the meat fully.
A growing problem is impaired HCl production. It’s estimated that about 40-50% of the US populations suffers from low stomach acid levels. Without enough HCl, pepsinogen can not be converted into pepsin, which means that you can not break down the protein in your food. Don’t be fooled into thinking it will be broken down later in the intestinal tract either. The intestines are more involved in the final stages of digestion and more importantly absorption. If you don’t break down the large compounds of food like protein and fiber in the stomach, you will not be getting the valuable nutrients from your diet. Cruciferous vegetables are known for their estrogen-detoxification properties through the production of Diindolylmethane from Indole 3C, but this extraction cannot occur without an adequate amount of HCl.
Not producing enough HCl also makes you more prone to bacterial and fungal overgrowths and parasites. These can further hamper your digestion and have numerous other negative health impacts on your body. Low HCl also puts you at greater risk for food poisoning and infections. Low HCl production is also associated with increased risk in gastric cancer and many disease related to nutrient deficiencies. For instance low B12 is associated with Alzheimer’s but many of these cases are because they don’t produce enough stomach acid to absorb the B12.
Signs you are not producing enough HCl
- Belching or gas within one hour of a meal
- Bloating and fullness shortly after eating
- Loss of taste for meat
- Nausea after taking supplements
- Brittle fingernails
- Undigested food in stool
- Foul-smelling stools
- Stomach pain
- Bad breath
- Loss of appetite
- Estrogen buildup
- Acne rosacea
Stomach acid is also important for signaling later processes in digestion to digest fats and carbohydrates. Look for some of those topics to come up in Digestion 102.
A few good reads on HCl from Charles Poliquin