Library · Molecule
Short chain fatty acids
Make it clearer
Fiber from plant foods is not digested in the small intestine: it reaches the large intestine intact. Waiting there are the bacteria of the microbiota, and in particular the anaerobic ones, which live without oxygen. Those bacteria ferment it, and the end products of that fermentation are the short chain fatty acids.
Three of them show up in the largest amounts: acetate, propionate, and butyrate. And the fermentation happens mostly in the first part of the colon.
What is interesting is how little of them leaves the body. The vast majority of what gets produced is absorbed by the colonocytes, the cells that line the inside of the colon, and only a fraction ends up in the stool.
And most butyrate does not even travel: the colonocyte that absorbs it burns it as its own fuel. It is like a factory that drops the fuel at the door of the house that is going to use it.
In brief
Short chain fatty acids are the end product of the fermentation of fiber, which resists digestion and reaches the large intestine.
The anaerobic microbiota mainly produces acetate, propionate, and butyrate, and does so mostly in the proximal colon.
Colonocytes absorb nearly all of them, and only a fraction leaves in the stool.
Most butyrate is used up as fuel by the colonocyte itself.
A factory that drops the fuel at the door of the house that burns it.
Sources (2)
- National Library of Medicine (PubMed Central), Journal of Lipid ResearchThe role of short-chain fatty acids in the interplay between diet, gut microbiota, and host energy metabolism, Journal of Lipid ResearchPublished
- National Center for Biotechnology Information, StatPearls PublishingThe Role of Dietary Fiber in Health Promotion and Disease Prevention: A Practical Guide for Clinicians, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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