MCFAs

Medium-chain fatty acids (MCFAs) are fatty acids with a chain length of six to twelve carbon atoms. The most common examples are caproic (C6:0), caprylic (C8:0), capric (C10:0), and lauric (C12:0) acids. In some classifications lauric acid is variably categorized as medium- or long-chain, reflecting differences in chemical properties and metabolism.

MCFAs are more water-soluble than long-chain fatty acids and are absorbed directly into the portal circulation after digestion. They are transported to the liver, where they are rapidly oxidized for energy. This can lead to a lower tendency to be stored as adipose tissue and, in some contexts, to increased production of ketone bodies.

Dietary sources and products: Coconut oil and palm kernel oil are rich in MCFAs. Dairy fats also contain MCFAs, though in smaller amounts. In nutrition and medicine, medium-chain triglycerides (MCTs) are fats in which the fatty acids are predominantly MCFAs; MCT oil is a refined supplement containing mainly caprylic and capric acids and is used to increase energy intake or support fat absorption in certain medical conditions.

Health effects and use: Evidence on weight management is mixed; some studies report modest improvements in energy expenditure or satiety, while others find no large effect. MCFAs may aid energy metabolism in fat-malabsorption conditions, and caprylic acid has demonstrated antimicrobial activity in some contexts. Ketogenic diets may leverage MCFAs to promote ketosis.

Safety: Dietary MCFAs from foods are generally safe for most people. High intake of MCT oil can cause gastrointestinal upset, including diarrhea, bloating, and cramps. As with other fats, consumption should fit within overall dietary guidelines.