Glossary /
Gut Microbiome
The trillions of bacteria, archaea, fungi, and viruses living in your intestines that shape digestion, immunity, and mood.
What it is
By cell count, you are more microbe than human. Most of those microbes live in the large intestine, where they ferment fiber into short-chain fatty acids (butyrate, propionate, acetate), synthesize vitamins, and constantly negotiate with the immune cells lining the gut wall. The composition is established in early childhood and shifts with diet, antibiotics, sleep, and stress.
Why it matters
A diverse, fiber-fed microbiome is one of the strongest predictors of healthspan we can measure. Low diversity correlates with metabolic disease, autoimmunity, and depression. The fastest way to influence yours is the simplest: eat thirty or more different plant species across a week, sleep enough that the gut lining can repair, and avoid unnecessary antibiotics. Fancy probiotic supplements rarely outperform a real diet.