Gut Health & Digestion

The stations: the mouth — where chewing is the free first step of digestion and saliva's enzymes begin starch before you swallow (the most underused lever on the page). The stomach — acid at pH ~1.5–2 unfolding proteins, releasing B12 from its food-bound form, and defending against pathogens (the acid story ties directly to the B12 and iron chapters: suppress it long-term with medications, and absorption of both quietly falls). The small intestine — enzymes and bile dismantling fat and starch across an absorption surface of roughly 250 square meters, where the Iron & Nutrition page's pairing chemistry actually happens. And the colon — handed the residue, hosting the residents the Microbiome page covers.

The rhythm: the pipeline moves in waves — peristalsis for transport, and the migrating motor complex: housekeeping contractions that sweep residue downstream, running only in the gaps between meals. This is the quiet cost of all-day grazing — a system that never fasts never cleans. Transit moves faster with movement itself (the post-meal walk is a digestive tool as much as a glucose one), with fiber and water setting the traffic's texture.

The symptom science: bloating is mostly gas from fermentation plus transit speed — not automatically a food enemy (the guided journey exists to narrow it honestly). Reflux is the lower esophageal gate misbehaving — its honest levers are timing (finish meals earlier, stay upright after), volume, and weight, ahead of any food-blame list. And the functional-symptom territory (IBS and neighbors) is exactly where clinical partnership beats elimination-diet roulette — the Microbiome page's red flags apply here unchanged.

The shelf, graded: digestive enzymes — mostly unnecessary unless the pancreas actually fails (a clinical diagnosis, not a wellness feeling). Bitters and 'gut-healing protocols' — tradition dressed as mechanism, with thin trial support. HCl betaine — self-experimenting with stomach acid is genuinely dangerous without guidance. The pipeline's honest levers are behavioral — chewing, slowing, leaving gaps, managing stress (the gut-brain wiring pauses digestion in real time) — and food-form, which is the other pages' whole story.

• Chewing is the free first step — the most underused lever on the page.
• Stomach acid releases B12 and defends the gate; suppressing it long-term has absorption costs.
• Housekeeping waves run only between meals — grazing all day cancels the cleaning cycle.
• Movement moves the pipeline — the post-meal walk is a digestive tool.
• Bloating is fermentation plus transit — not automatically a food verdict.
• Enzymes, bitters, and betaine HCl: mostly the shelf's mythology, graded below its labels.