WHAT ARE MCTs?
- MCTs are fats with fatty acids between 6 and 12 carbon chains in length
- The most active MCTs are those containing 6-10 chain length fatty acids (caproic, caprylic, and capric acids)
- They can be transported directly to the liver, from the gut, to be converted into ketones
- These ketones provide a beneficial fuel for the body and brain
Medium Chain Triglycerides (MCTs) are a particular type of dietary fat. 'Fat' itself is the term lay-term we use for a 'triglyceride'. A triglyceride consists of a glycerol 'backbone' with three 'fatty acids' attached to it. Dietary fats that we eat are almost always triglycerides but most contain long fatty-acid chains (greater than twelve carbons in length). MCTs are rarer in the diet and are found in small amounts in dairy foods and in palm and coconut oils. Coconut oils are especially rich in a medium chain fatty acid called 'lauric acid' that is 12 carbons in length. The other medium-chain fatty acids (MCFA) are fatty acids comprised of 6-10 carbons in chain. These MCTs are: caproic (C6), caprylic (C8), and capric (C10) acids.1
Long chain fats, which include most the dietary fats that we eat, require the action of bile and phospholipids in the gut to break up the fat into smaller 'packets' for digestion and once they have been absorbed into the intestinal wall they are bundled up into chylomicrons (a protein transport molecule) so that they can be delivered to the body via the lymphatic system. Medium Chain Triglycerides do not require the actions of bile, and rather than the standard absorption and transport pathways, they are instead transported directly to the liver for conversion into bio-available ketone fuels. Early animal studies demonstrated the ketogenic (ketone producing) effect of MCTs and indicated an approximately nine-fold increase in ketone body production after ingestion of MCT versus LCT2, 3 and it is well known that MCTs promote both an immediate boost in ketones and encourage the creation of ketones from other fat types in both animals 2, 3 and in humans 4.
1. Mingrone G, Greco AV, Castagneto M, De Gaetano A, Tataranni PA, Raguso C. Kinetics and thermogenesis of medium-chain monocarboxylic and dicarboxylic acids in man: sebacate and medium-chain triglycerides. JPEN Journal Of Parenteral And Enteral Nutrition. 1993;17(3):257-64.
2. Jiang ZM, Zhang SY, Wang XR, Yang NF, Zhu Y, Wilmore D. A comparison of medium-chain and long-chain triglycerides in surgical patients. Annals Of Surgery. 1993;217(2):175-84.
3. Lai H, Chen W. Effects of medium-chain and long-chain triacylglycerols in pediatric surgical patients. Nutrition. 2000;16(6):401-6.
4. Sandström R, Hyltander A, Körner U, Lundholm K. Structured triglycerides were well tolerated and induced increased whole body fat oxidation compared with long-chain triglycerides in postoperative patients. JPEN Journal Of Parenteral And Enteral Nutrition. 1995;19(5):381-6.