198. Small Intestinal Bacterial Overgrowth & Hypochlorhydria | Low Stomach Acid, Intestinal Microbiome Dysbiosis, & a Brief Conversation on the Oral Microbiome

In this encore episode, we detail hypochlorhydria while reviewing gastric lining anatomy, highlighting hydrochloric acid (HCl) secretion and its role in digestion, micronutrient absorption, and microbial defense. We discuss potential downstream effects of hypochlorhydria, including impaired digestive signaling, bacterial overgrowth in the small intestine (SIBO), and more. Lastly, we detail upstream microbial control, focusing on possible influences of the oral microbiome and oral dysbiosis.

Topics:

1. Introduction

- Highlighting the stomach and hypochlorhydria / low stomach acid, as well as microbial balance, dysbiosis, and overgrowth.

- Discussion of intestinal microbiome and oral microbiome.

2. Gastric Anatomy and Mucosal Layers

- The stomach: cardia, fundus, body, pylorus.

- The gastric mucosa: epithelial lining, lamina propria, muscularis mucosae.

- The epithelial layer: mucous cells, parietal cells, chief cells, enteroendocrine cells.

- Beneath the mucosa: submucosa and muscular layers that contribute to gastric motility, mechanical digestion, and more.

3. Mucous Cells

- The surface epithelium and gastric pits.

- Secretion of thick, viscous mucus.

- Protecting the epithelium.

- The mucus traps bicarbonate ions: neutral microenvironment that protects against acid-induced damage.

4. Parietal Cells and Gastric Acid Secretion

- Secretion of hydrochloric acid (HCl): denatures dietary proteins, sterilizes ingested food.

- Parietal cells produce intrinsic factor: binds vitamin B12 to facilitate absorption in the ileum.

5. Chief Cells and Pepsinogen

- Secretion of pepsinogen: activated by low pH into the proteolytic enzyme pepsin.

- Pepsin and protein digestion.

- Release of gastric lipase.

6. Hydrochloric Acid: Digestive and Protective Roles

- Immune defense.

- Pepsinogen activation.

- Adequate gastric acidity essential for properly acidified chyme.

- Priming release of bile and pancreatic enzymes.

7. The Small Intestine, Stomach, and Microbial Regulation

- The pyloric sphincter.

- The stomach supports minimal microbial diversity.

- Acidic barrier aids in limiting the entry of opportunistic microbes into the small intestine.

8. Hypochlorhydria, Low Stomach Acid

- Hypochlorhydria can compromise one of the body's defense mechanisms.

- Colonization of the small intestine.

- Insufficient pepsinogen activation and possible protein digestion impairment.

- Suboptimal chyme formation and downstream digestive capacity.

- Possible symptoms of hypochlorhydria.

- Possible impaired absorption of micronutrients including vitamin B12, iron, calcium, magnesium.

- H. pylori infection, autoimmunity, aging.

9. The Oral Microbiome, Intestinal Microbiome, and Dysbiosis

- Oral and environmental microbes.

- Altered gastric pH, bile, digestive enzymes, and more.

- The oral cavity as the gateway to the GI tract.

- Oral microbial species.

- Oral hygiene and oral microbiome health.

10. Conclusion

- Root-cause approach.

Thank you to our episode sponsor:

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