POSTBIOTIC SCIENCE

Beyond Probiotics — The Metabolites Doing the Real Work.

Postbiotics — the bioactive metabolic compounds produced by gut bacteria during fermentation — represent the next frontier beyond probiotics and prebiotics. While probiotics introduce living bacteria and prebiotics feed them, postbiotics are the actual output that produces health effects: short-chain fatty acids (butyrate, propionate, acetate) that fuel colonocytes, seal the gut barrier, regulate appetite, and reduce systemic inflammation; urolithins that activate mitophagy in muscle cells; equol derived from soy isoflavones that modulates oestrogen receptor activity; trimethylamine N-oxide (TMAO) produced from red meat and eggs with cardiovascular implications; and indole-3-propionic acid that protects neuronal function. Understanding postbiotics explains why the same probiotic strain has wildly variable effects in different individuals — the microbiome ecosystem producing the postbiotics matters more than the supplemented strain alone.