When it comes to the digestive system, the stomach is often under-appreciated. Most of us just think of it as a place to store food after we swallow it and before we digest and absorb it, but so much more happens in this organ.
The stomach can hold up to three liters (not quite a gallon for those non-metric people) of food and food stays in the stomach for up to about 4 hours. Fats and fiber will keep food in the stomach longer. The only things that actually get absorbed into the body from stomach are water, alcohol and aspirin. Think about how fast alcohol goes to your head when you drink on an empty stomach! The stomach acts like a blender, it crushes, churns and mixes the contents into a mushy mixture called chyme.
The stomach has millions of cells called parietal cells that are responsible for constantly manufacturing hydrochloric acid. This is why the gastric juice is so acidic, it is normally a pH of 1-2. The acid in the stomach is so important for the digestion of proteins, the activation of important digestive enzymes and the killing of any pathogenic organisms that may have hitched a ride on the food you swallow. I don’t want to be the bearer of bad news here but what we eat is nowhere near sterile. You really want some acid in there!
The acid would burn a hole in the stomach if it were not for mucus-producing cells. These cells produce a thick mucus slime layer that coats the tissue and protects it from the acid. If there is a break in this mucus layer, ulcers can form in the stomach.
Don’t forget the stomach produces hormones as well. Remember ghrelin the “hunger hormone”? It’s produced in the stomach and tells your brain that you are hungry.
The same cells that make stomach acid also produce something called intrinsic factor. Intrinsic factor travels from the stomach into the intestines and allows us to absorb vitamin B12. Acid blocking drugs that are often taken for heartburn (GERD) will decrease the function of the parietal cells. It takes a whole bunch of energy to make hydrochloric acid and it turns out that these cells become less functional as we age and also when we are under a ton of stress.
The most common conditions that affect the stomach are:
Gastritis (an infection in the stomach)
Gas and Bloating
Pernicious Anemia - a type of anemia called due to a lack of vitamin B12; remember that intrinsic factor is made in the stomach
Gastroparesis - decreased emptying of the stomach
Hypochlorhydria - low stomach acid
Talk to a naturopathic doctor or a functional medicine practitioner if you want to learn if your digestive system is functioning optimally.