Short-chain fatty acids (SCFAs)
Molecules (butyrate, propionate, acetate) produced when gut microbiota ferment fibre, with major roles in gut, metabolic and brain health.
SCFAs are the star products of fermentation of fibre and resistant starch by bacteria in the colon. The three main ones:
- Butyrate: the preferred fuel of colon cells (colonocytes), anti-inflammatory
- Propionate: regulates blood glucose and cholesterol (liver)
- Acetate: the most abundant, an energy source and a signal to various organs
An original angle (the microbiota’s messengers): SCFAs are much more than fermentation “waste”. They are signalling molecules that link the microbiota to the rest of the body:
- Gut barrier: butyrate feeds and strengthens colon cells, helping prevent leaky gut
- Immunity: they regulate immune cells and modulate inflammation (promoting regulatory T cells)
- Metabolism: they stimulate the secretion of satiety hormones (GLP-1, PYY), hence fibre’s appetite-suppressing effect
- Gut-brain axis: they cross the barrier and influence mood, appetite and even neuroinflammation
Butyrate is particularly valuable: it has anti-colorectal-cancer properties (it induces the death of cancerous colon cells while nourishing healthy cells, the butyrate paradox).
How can you boost your SCFAs? Eat a varied range of fermentable fibre (vegetables, pulses, oats), resistant starch and fermented foods. A diverse microbiota produces more SCFAs, as each type of fibre feeds different bacteria.