Short-chain fatty acids (SCFAs) are carbon chains made up of anywhere from two to six carbon atoms. Each one has a different function depending on its length and structure. The most important medicinal short-chain fatty acid is butanoic acid (butyric acid). Short-chain fatty acids are naturally produced when we break down dietary fibre in our large intestine.

Types of Short-Chain Fatty Acids

Each length of carbon chain has a particular name based on its structure, and all have different functions. Some of the longer chains, like butyric acid and valeric acid, actually have isomers that have the same chemical formula but a mirror image structure that also gives them a different function. Common SCFAs are formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid, valeric acid, and isovaleric acid. See the chart below for more information on each.

Nutritional Information

# of carbons
name
function
2
formic acid
found in bee venom and used for fermentation, tanning and cleaning.
3
acetic acid
major constituent in vinegar and used in pickling and for cleaning.
4
propionic acid
inhibits the growth of mold and some bacteria. may contribute to acne.
5butanoic (butyric) acid
found in milk (esp. goat, and sheep) and fermented dairy products. mediates inflammation in the colon.
5isobutyric acid
isomer of butyric acid found in carob and arnica root.
6
valeric acid
found in valerian root, and causes the strong smell associated with this herb.
6isovaleric acid
isomer of valeric acid found in some essential oils, valerian root, and is responsible for the smell of “stinky feet”.

Medicinal Short-Chain Fatty Acids

Although some of the short-chain fatty acids may be useful in everyday life and manufacturing for cleaning and preservation, there are others that have been found to be particularly useful for health. The most important of these is butanoic acid. Butanoic acid was formerly known as butyric acid, which, when conjugated with a base, forms butyrate. Butyrate is now correctly called butanoate, although both names can still be seen on product labels and in research papers.

Butyrates/Butanoates

There are many forms of butyrate available, such as salts of methyl butyrate, ethyl butyrate, butyl butyrate, and pentyl butyrate. Alternatively, butyrate can be part of a larger molecule and the name will contain “-butyro-“ within it. The presence of this fatty acid is extremely beneficial to colon health and can directly reduce colon inflammation. Some forms of butyrate have been found to have the potential to stop unhealthy cell growth and to slow the progression of Alzheimer’s disease in animal models.

Adding Short-Chain Fatty Acids To Your Diet

The source of each short-chain fatty acid is relatively unique. Those that have the most use in the human body are commonly manufactured from dietary fibre in our colon. For direct supplementation, butyrate is the most commonly sought-after short-chain fatty acid.