How Short-Chain Fatty Acids Affect Health and Weight

Short-chain fatty acids are produced by the friendly bacteria in your gut.
In fact, they are the main source of nutrition for the cells in your colon.
Short-chain fatty acids may also play an important role in health and disease.
They may reduce the risk of inflammatory diseases, type 2 diabetes, obesity, heart disease and other conditions.
This article explores how short-chain fatty acids affect health.

What Are Short-Chain Fatty Acids?

Short-chain fatty acids are fatty acids with fewer than 6 carbon (C) atoms.
They are produced when the friendly gut bacteria ferment fiber in your colon, and are the main source of energy for the cells lining your colon.
For this reason, they play an important role in colon health.
Excess short-chain fatty acids are used for other functions in the body. For example, they provide roughly 10% of your daily calorie needs.
Short-chain fatty acids are also involved in the metabolism of important nutrients like carbs and fat.
About 95% of the short-chain fatty acids in your body are:

• Acetate (C2).
• Propionate (C3).
• Butyrate (C4).

propionate is mainly involved in producing glucose in the liver, while acetate and butyrate are incorporated into other fatty acids and cholesterol.
Many factors affect the amount of short-chain fatty acids in your colon, including how many microorganisms are present, the food source and the time it takes food to travel through your digestive system.

Bottom Line: Short-chain fatty acids are produced when fiber is fermented in the colon. They act as a source of energy for the cells lining the colon.

Food Sources of Short-Chain Fatty Acids

Eating a lot of fiber-rich foods, such as fruits, vegetables and legumes, is linked to an increase in short-chain fatty acids.
One study of 153 individuals found positive associations between a higher intake of plant foods and increased levels of short-chain fatty acids in stools.
However, the amount and type of fiber you eat affects the composition of bacteria in your gut, which affects what short-chain fatty acids are produced.
For example, studies have shown that eating more fiber increases butyrate production, while decreasing your fiber intake reduces production.
The following sources of fiber are best for the production of short-chain fatty acids in the colon:

• Inulin: You can get inulin from artichokes, garlic, leeks, onions, wheat, rye and asparagus.
• Fructooligosaccharides (FOS): FOS can be extracted from the blue agave plant and is found in the Jerusalem artichoke.
• Resistant starch: You can get resistant starch from grains, barley, rice, beans, green bananas, legumes and potatoes that have been cooked and then cooled.
• Pectin: Good sources of pectin include apples, apricots, oranges and others.
• Arabinoxylan: is found in plant cell walls.
• Guar gum: Guar gum can be extracted from guar beans, which are legumes.
• Dairy: Certain cheeses, butter and cow’s milk contain butyrate.

Bottom Line: High-fiber foods, such as fruits, veggies, legumes and whole grains, encourage the production of short-chain fatty acids.

Short-Chain Fatty Acids and Digestive Disorders

Short-chain fatty acids may be beneficial against some digestive disorders.
For example, butyrate has anti-inflammatory effects in the gut .

Diarrhea

Your gut bacteria convert resistant starch and pectin to short-chain fatty acids, and eating them has been shown to reduce diarrhea in children .

Inflammatory Bowel Disease

Ulcerative colitis and Crohn’s disease are the two main types of inflammatory bowel disease (IBD). Both are characterized by chronic bowel inflammation.
Because of its anti-inflammatory properties, butyrate has been used to treat both of these conditions.
Studies in mice have shown that butyrate supplements reduce bowel inflammation, and acetate supplements had similar benefits. Additionally, lower levels of short-chain fatty acids were linked to worsened ulcerative colitis .
Human studies also suggest that short-chain fatty acids, especially butyrate, can improve symptoms of ulcerative colitis and Crohn’s disease.
A study involving 22 patients with ulcerative colitis found that consuming 60 grams of oat bran every day for 3 months improved symptoms.
Another small study found that butyrate supplements resulted in clinical improvements and remission in 53% of Crohn’s disease patients.
For ulcerative colitis patients, an enema of short-chain fatty acids, twice per day for 6 weeks, helped reduce symptoms by 13%.