Volatile fatty acids

Short-chain fatty acids (SCFAs), also referred to as volatile fatty acids (VFAs), are fatty acids with two to six carbon atoms. Free SCFAs can cross the blood-brain barrier via monocarboxylate transporters.

Short-chain fatty acids are produced when dietary fiber is fermented in the colon.

Short-chain fatty acids and medium-chain fatty acids are primarily absorbed through the portal vein during lipid digestion, while long-chain fatty acids are packed into chylomicrons and enter lymphatic capillaries, and enter the blood first at the subclavian vein.

The short-chain fatty acid butyrate is particularly important for colon health because it is the primary energy source for colonic cells and has anti-carcinogenic as well as anti-inflammatory properties that are important for keeping colon cells healthy. Butyrate inhibits the growth and proliferation of tumor cell lines in vitro, induces differentiation of tumor cells, producing a phenotype similar to that of the normal mature cell, and induces apoptosis or programmed cell death of human colorectal cancer cells. Butyrate inhibits angiogenesis by inactivating Sp1 transcription factor activity and downregulating VEGF gene expression.

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