Which nutrient is fermented by bacteria in the colon into short chain fatty acids?

Which nutrient is fermented by bacteria in the colon into short chain fatty acids?

• A. Fiber
• B. Protein
• C. Fats
• D. Vitamins

Answer: (A)

Bacteria in the colon primarily ferment nondigestible carbohydrates found in dietary fiber to produce short-chain fatty acids. These SCFAs, such as acetate, propionate, and butyrate, rise from fiber fermentation and provide energy to colonocytes (butyrate in particular is a key fuel for the colonic lining) while also supporting gut health and anti-inflammatory effects. The other options don’t fit this specific process: fats are largely absorbed earlier in the digestive tract and aren’t a major substrate for colon fermentation; proteins can be fermented by gut bacteria but mainly yield different metabolites (like ammonia and branched-chain fatty acids) rather than the typical SCFAs; vitamins produced by gut bacteria are a separate microbial function and not the product of fermenting into SCFAs.

Bacteria in the colon primarily ferment nondigestible carbohydrates found in dietary fiber to produce short-chain fatty acids. These SCFAs, such as acetate, propionate, and butyrate, rise from fiber fermentation and provide energy to colonocytes (butyrate in particular is a key fuel for the colonic lining) while also supporting gut health and anti-inflammatory effects. The other options don’t fit this specific process: fats are largely absorbed earlier in the digestive tract and aren’t a major substrate for colon fermentation; proteins can be fermented by gut bacteria but mainly yield different metabolites (like ammonia and branched-chain fatty acids) rather than the typical SCFAs; vitamins produced by gut bacteria are a separate microbial function and not the product of fermenting into SCFAs.