Collaborative JPEN‐Clinical Nutrition Scientific Publications Role of intestinal bacteria in nutrient metabolism

Abstract
The human large intestine contains a microbiota, the components of which are generically complex and metabolically diverse. Its primary function is to salvage energy from carbohydrate not digested in the upper gut. This is achieved through fermentation and absorption of the major products, short chain fatty acids (SCFA), which represent 40-50% of the available energy of the carbohydrate. The principal SCFA, acetate, propionate and butyrate, are metabolized by the colonic epithelium (butyrate), liver (propionate) and muscle (acetate). Intestinal bacteria also have a role in the synthesis of vitamins B and K and the metabolism of bile acids, other sterols and xenobiotics.