pH of gastric juice

The pH value of gastric juice varies (gastric acid) depending on the person's genetic structure, the Helicobacter pylori population in the person's stomach, and the type of diet. Gastric juice plays a key role in the digestion of proteins by activating digestive enzymes, which together break down the long chains of amino acids of proteins. In addition, many microorganisms are inhibited or destroyed in an acidic environment, preventing infection or sickness. This level rises when food enters the stomach; it can reach up to six, but it lowers again throughout digestion as stomach acid is secreted.

There is no one opinion about normal ranges for acidity of gastric juice. In some cases, the normal values considered in the range 1.2-2.0, others said that pH lower than 1.5 and higher than 3.5 can be a sign of pathological changes in the stomach and GI.

The active components of gastric acid are protons and chloride. Often simplistically described as hydrochloric acid, these species are produced by parietal cells in the gastric glands in the stomach.

Gastric juice isn't just acid and enzymes, but a complex mixture of several chemicals, namely water, mucous, hydrochloric acid, pepsinogen, hormones and electrolytes, gastric lipase, intrinsic factor and amylase.

Gastric acid production is regulated by both the autonomic nervous system and several hormones. The parasympathetic nervous system, via the vagus nerve, and the hormone gastrin stimulate the parietal cell to produce gastric acid, both directly acting on parietal cells and indirectly, through the stimulation of the secretion of the hormone histamine from enterochromaffin-like cells (ECL). Vasoactive intestinal peptide, cholecystokinin, and secretin all inhibit production.

The production of gastric acid in the stomach is tightly regulated by positive regulators and negative feedback mechanisms. Four types of cells are involved in this process: parietal cells, G cells, D cells and enterochromaffin-like cells. Besides this, the endings of the vagus nerve (CN X) and the intramural nervous plexus in the digestive tract influence the secretion significantly.

Abnormalities. Disorders or diseases caused or related.

Lower gastric acidity (means less acidic, the gastric pH value is upper than 3.5).

In hypochlorhydria and achlorhydria, there is low or no gastric acid in the stomach potentially leading to problems as the disinfectant properties of the gastric lumen are decreased. In such conditions, there is greater risk of infections of the digestive tract (such as infection with Vibrio or Helicobacter bacteria).

In diseases featuring excess vomiting, patients develop hypochloremic metabolic alkalosis (decreased blood acidity by H+ and chlorine depletion).

Helicobacter pylori (H. pylori) infection induces corpus-predominant gastritis with hyposecretion of acid in some subjects. These infected subjects have an increased risk of developing gastric cancer (GC).

Low gastric acid can leave the body vulnerable to a number of diseases and health complications. If the body doesn’t receive necessary nutrients, it can become vitamin or mineral deficient.

Inadequate stomach acid levels have been associated with a number of health conditions, including:

·        upset stomach

·        nausea

·        acid reflux

·        heartburn

·        malnutrition

·        skin issues

·        osteoporosis

·        leaky gut syndrome

·        diabetes

·        cancer

·        asthma

·        rheumatoid arthritis

·        small intestinal bacterial overgrowth (SIBO)

There are a number of contributing factors for low stomach acid. Stress and a poor diet are two of the more common reasons that can directly affect the digestive process.

Other factors that may cause low stomach acid include:

·        eating too quickly

·        high sugar intake

·        zinc deficiency

·        age

·        antacid medication and prescription drugs

·        food sensitivities or allergies

·        infection

·        chronic illness

Higher gastric acidity (the value gastric pH is lower than 1.5)

Helicobacter pylori (H. pylori) infection is an important biological factor that can induce marked alterations in the gastric acid secretion of hosts. In subjects with antrum-predominant gastritis following H. pylori infection there is increased release of gastrin and consequently increased acid secretion. Such subjects have an increased risk of developing duodenal ulcers (DU).

Gastric juices can lead to mucosal damage when they enter the esophagus. Patients with gastroesophageal reflux diseases (GERD) may develop esophageal breaks, along with damage to the enamel of the teeth caused by the high acidity of the stomach contents.

In Zollinger–Ellison syndrome and hypercalcemia, there are increased gastrin levels, leading to excess gastric acid production, which can cause gastric ulcers.

Note 4: Medically reviewed by Kevin Martinez, M.D. — Written by Kimberly Holland on October 2, 2020 https://www.healthline.com/health/how-strong-is-stomach-acid

Note 5: Elaine N. Marieb, Katja Hoehn, Katja N. Hoehn (2018). Human Anatomy and Physiology, 11th edition. Pearson Education, Inc. p. 1264. ISBN 978-0134580999.

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