Gastroesophageal reflux disease (GERD) is a symptom of a lack of stomach acid. As stomach acidity declines the lack of stomach acid leads to fermentation of foods that are not being properly digested. This can also lead to an overgrowth of stomach yeast, which also contributes to fermentation.
Proteins in particular are essential for the breakdown of protein as sufficient stomach acid is essential for the protein digestive enzyme pepsin to function. A lack of stomach acid leads to proteins not being digested properly. So the proteins only partially digest and in essence rot in the gut leading to gas formation. This leads to heartburn as explained below.
When we are younger our acids produce sufficient stomach acid to control yeast growth. But as we age stomach acidity naturally declines. This helps explain why as we age we develop more nutritional deficiencies, and get more frequent heartburn. Minerals and some B vitamins require sufficient stomach acid to be absorbed. And silica, which helps maintain healthy bones, blood vessels, skin, etc. has to be converted in to orthosilicic acid to be absorbed. Some silica gets converted just by natural reaction with water, though the conversion of silica to orthosilicic acid is enhanced by sufficient stomach acid. Drops in the absorption of orthosilicic acid leads to osteoporosis, wrinkles, etc.
Overgrowth of yeast in the stomach leads to heartburn due to fermentation from the yeast. This fermentation leads to the production of carbon dioxide gas, which creates the bloating. The gas also produces pressure on the sphincter muscle at the upper end of the stomach. Like other muscles this muscle can get tired. When the sphincter muscle tires out from fighting the pressure the muscle relaxes allowing the gas to escape up the esophagus. As the gas goes up the esophagus traces of stomach acid are carried with it causing the heartburn.
Excessive stomach acid is a medical condition known as hyperchlorhydria, and medical texts tell us it is extremely rare. Yet antacids and acid blockers are the second largest selling drug class. This stems from the outdated notion that acid reflux involves too much stomach acid. But the fact is that these drugs can actually make the condition worse by neutralizing the remaining acid, or by preventing its secretion. Further reducing stomach acidity just encourages more yeast growth. An easier way to look at this principle is when taking antibiotics, women can develop vaginal yeast infections. The reason for this is that the flora that inhabit the vaginal cavity produce lactic acid to maintain slightly acidic tissues, which yeast cannot grow in. Since the antibiotics kill these bacteria, they also lead to a shift in the pH of the tissues to the alkaline side leading to an overgrowth of yeast.
There are several things that can be done. In Europe digestive bitters are very popular for treating heartburn. These are bitter tasting herbs, usually sold in liquid form since they must come in to contact with the tongue to work. Bitters work by stimulating the bitter receptors on the back of the tongue. This in turn stimulates a nerve, known as the vagus nerve. This in turn increases the production of stomach acid, bile secretion and pancreatic enzyme secretion. They also have a cleansing effect on the liver, and the bile increasing effects make it useful for dissolving cholesterol based gallstones. Since bitters do cleanse the liver it is important to drink a lot of water throughout the day when using them.
Bitters are not recommended in cases where the gallbladder has been removed.
Zinc can also help since it is a catalyst for the formation of hydrochloric acid for the stomach. The recommended dose is 50mg daily with a large meal.
B6 and folate are required for stomach acid formation. Natural sources are best. These include rice bran, oat bran, nutritional yeast, seaweeds, pollen and nettle leaf.
Salt is also required for the production of stomach acid. The salt is split leaving sodium that becomes sodium bicarbonate and chloride, which can be used to form stomach acid (hydrogen chloride). I do not recommend large amounts, but it is a bad idea to severely restrict salt intake. And I do not recommend refined table salt, but rather trace element salts such as unrefined sea salts or mined mineral salts such as Real Salt. Seaweeds also provide natural salts as well as the B vitamins needed for stomach acid formation.
The final option is betaine HCl, derived from beet leaves. Betaine HCl is very acidic, with a pH of 1. So it needs to be taken with food already in the stomach. Although, I do not believe in substituting for the body's own job long term since it can become dependent on the substitution. So Betaine HCl is best used occasionally.
It is very important to avoid antacids, acid blockers, alkaline waters, and any other thing neutralizes stomach acid or inhibits its formation. These include calcium carbonate (coral, oyster shell, dolomite), calcium oxide/hydroxide (lime) and magnesium oxide/hydroxide.
Stomach acid is important for a number of reasons other than digestion. It is also important for the absorption of minerals and some B vitamins. Stomach acid is also a primary defense against pathogens entering our bloodstream through the digestive system. Lack of stomach acid can also lead to allergies from undigested proteins being absorbed through the gut.