Achlorhydria

Achlorhydria or hypochlorhydria refers to states where the production of gastric acid in the stomach is absent or low, respectively. It is associated with various other medical problems.

Signs and symptoms
The decreased acid level itself can cause symptoms similar to gastroesophageal reflux disease, and impairs protein digestion by inhibiting the activation of the enzyme pepsin, whose activation is dependent upon a low gastric pH. Furthermore, low acid levels in the stomach are linked with bacterial overgrowth (as the stomach does not kill microbes normally present in food), which can manifest as diarrhea or decreased absorption of nutrients or vitamins. Risk of particular infections, such as Vibrio vulnificus (commonly from seafood) is increased. Even without bacterial overgrowth, low stomach acid can lead to nutritional deficiencies through malabsorption of basic electrolytes (magnesium, zinc, etc.) and vitamins (including vitamin C, vitamin K, and the B complex of vitamins). Such deficiencies may be involved in the development of a wide range of pathologies, from fairly benign neuromuscular issues to life-threatening diseases. A person with achlorhydria can suffer from stomach pains caused by the digestion of food that is not properly broken down by gastric acid.

Causes

 * The slowing of the body's basal metabolic rate associated with hypothyroidism
 * Autoimmune disorders where there is antibody production against parietal cells which normally produce gastric acid.
 * The use of antacids or drugs that decrease gastric acid production (such as H2-receptor antagonists) or transport (such as proton pump inhibitors).
 * A symptom of rare diseases such as mucolipidosis (type IV).
 * A symptom of Helicobacter pylori infection which neutralizes and decreases secretion of gastric acid to aid its survival in the stomach.
 * A symptom of pernicious anemia, atrophic gastritis or of stomach cancer.
 * Radiation therapy involving the stomach.
 * Gastric Bypass procedures such a Duodenal Switch and RNY, where the largest acid producing parts of the stomach are either removed, or blinded.
 * VIPomas (vasoactive intestinal peptides) and somatostatinomas are both islet cell tumors of the pancreas.

Diagnosis
90% of all patients with achlorhydria have detectable antibodies against the H+/K+ ATP-ase proton pump. The diagnosis is made if the gastric pH remains high (>4.0) despite maximum pentagastrin stimulation. High gastrin levels are often detected.

Treatment
Treatment focuses on addressing the underlying cause of symptoms. Many health practitioners recommend meal-time supplementation with betaine hydrochloride (also known as betaine HCL) to increase gastric acidity and allow for proper digestion. Betaine HCL should not be confused with betaine in the form of DMG (dimethylglycine) or TMG (trimethylglycine), which are sweet-tasting and non-acidic. Unlike TMG/DMG, betaine HCL includes chloride, which breaks down into hydrochloric acid in the stomach, facilitating a lower pH and improving the breakdown of food. Betaine HCL is typically sold as a preparation containing pepsin, a digestive enzyme.

In addition to taking steps to lower the pH of the stomach, supplementation with minerals and vitamins such as vitamin B12 (which is poorly absorbed in achlorhydria/hypochlorhydria due to the absence of intrinsic factor) is usually recommended to compensate for malabsorption of nutrients. Foods with high microbial loads (including dairy products that intentionally contain microbes such as penicillin) are usually avoided. Because the acidity of the stomach is a primary defense against infection of the gastrointestinal tract, antifungals, probiotics, and antibiotics may be needed to treat recurring infections.

Prognosis
Little is known on the prognosis of achlorhydria, although there have been reports of an increased risk of gastric cancer.