GLOSSARY

Short-chain fatty acids (SCFA) are fatty acids with fewer than 6 carbons, produced mainly by colonic bacteria through fibre fermentation; they serve as fuel for colonic cells and as important signalling molecules for the body’s metabolism and immunity.

Main Types

• Acetate (2 carbons; about 60 percent): enters the general circulation; fuels muscle and the heart and is a precursor of cholesterol and fat.
• Propionate (3 carbons; about 20 percent): taken up by the liver; a substrate for gluconeogenesis; may inhibit cholesterol synthesis.
• Butyrate (4 carbons; about 20 percent): the main fuel of colonocytes (supplying about 60–70 percent of their energy).

Effects