Définition
The gut microbiome is the ecosystem of trillions of microorganisms inhabiting the gastrointestinal tract. It regulates inflammation, immune function, hormone metabolism, neurotransmitter production, and metabolic health. Diversity of gut bacteria is one of the most consistent markers of health and biological age.
The human gut microbiome contains approximately 38 trillion microbial cells — more than the total number of human cells in the body — representing hundreds to thousands of distinct species. This ecosystem evolved in co-dependency with the human host over millions of years and performs functions the body cannot execute independently.
Key microbiome functions relevant to women's health: gut bacteria produce short-chain fatty acids (SCFAs), particularly butyrate, propionate, and acetate, by fermenting dietary fiber. Butyrate is the primary energy source for colonocytes (intestinal lining cells) and a potent suppressor of intestinal inflammation via NF-κB inhibition. Microbiome diversity is required for adequate SCFA production — a narrow, low-diversity microbiome produces far less butyrate.
The estrobolome — the subset of gut bacteria that metabolize estrogens — is a critical link between gut health and hormonal balance. These bacteria produce beta-glucuronidase, an enzyme that deconjugates estrogen for reabsorption. Dysbiosis that alters estrobolome composition can impair estrogen recycling, contributing to both estrogen deficiency and excess depending on the direction of the imbalance.
Gut microbiome diversity is the most consistent correlate of biological age in microbiome research. The primary drivers of diversity: plant food variety (aiming for 30+ different plant foods per week), fermented food consumption, adequate fiber intake (30g+ daily), specific strains like Lactobacillus plantarum 299v for gut barrier integrity, and minimization of ultra-processed foods.
Ava Longevity · Built on the Ava Method · MMXXV