Short-chain fatty acids (SCFAs) are

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...

s with fewer than six

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, ...

s. Derived from

intestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

microbial fermentation of indigestible foods, SCFAs are the main energy source of colonocytes, making them crucial to

gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

health. SCFAs all possess varying degrees of water solubility, which distinguishes them from longer chain fatty acids that are immiscible.

List of SCFAs

Functions

SCFAs are produced when dietary fiber is fermented in the colon. Macronutrient composition (carbohydrate, protein, or fat) of diets affects circulating SCFAs. Acetate, propionate, and butyrate are the three most common SCFAs. SCFAs and

medium-chain fatty acid Medium-chain triglycerides (MCTs) are triglycerides with two or three fatty acids having an aliphatic tail of 6–12 carbon atoms, i.e. medium-chain fatty acids (MCFAs). Rich food sources for commercial extraction of MCTs include palm kernel oil a ...

s are primarily absorbed through the portal vein during

lipid digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...

, while

long-chain fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...

s are packed into chylomicrons, enter lymphatic capillaries, then transfer to the blood at the subclavian vein. SCFAs have diverse physiological roles in body functions. They can affect the production of lipids, energy and vitamins. They can also affect appetite and cardiometabolic health. Additionally they may have an impact on mental health and mood. The three main SCFAs, acetate, propionate and butyrate, were shown to lower blood pressure in experimental models, and clinical trials to determine their effect on hypertensive patients are underway. Butyrate is particularly important for colon health because it is the primary energy source for colonocytes (the epithelial cells of the colon). The liver can use acetate for energy.

List of SCFAs

Functions

See also

References

Further reading