Medium-chain triglyceride

Medium-chain triglycerides (MCTs) are triglycerides whose fatty acids have an aliphatic tail of 6–12 carbon atoms.

The fatty acids found in MCTs are called medium-chain fatty acids (MCFAs). Like all triglycerides, MCTs are composed of a glycerol backbone and three fatty acids. In the case of MCTs, 2 or 3 of the fatty acid chains attached to glycerol are medium-chain in length.

Rich sources for commercial extraction of beneficial MCTs include palm kernel oil and coconut oil.

List of MCFAs

Lipid number	Name		Salt/Ester Name		Formula		Mass (g/mol)	Appearance	Diagram
	Common	Systematic	Common	Systematic	Molecular	Structural
C6:0	Caproic acid	Hexanoic acid	Caproate	Hexanoate	C6H12O2	CH3(CH2)4COOH	116.16	Oily liquid
C8:0	Caprylic acid	Octanoic acid	Caprylate	Octanoate	C8H16O2	CH3(CH2)6COOH	144.21	Oily liquid
C10:0	Capric acid	Decanoic acid	Caprate	Decanoate	C10H20O2	CH3(CH2)8COOH	172.26	White crystals
C12:0	Lauric acid	Dodecanoic acid	Laurate	Dodecanoate	C12H24O2	CH3(CH2)10COOH	200.32	White powder

With regard to MCFAs, apart from the above listed straight chain (unbranched chain) fatty acids, side chain (branched chain) fatty acids, e.g. nonanoic acid, also exist.

Applications

Dietary relevance

Molecular weight analysis of milk from different species showed that while milk fats from all studied species were primarily composed of long-chain fatty acid (16 and 18 carbons long), approximately 10-20% of the fatty acids in milk from horses, cows, sheep, and goats were medium chain fatty acids.

Some studies have shown that MCTs can help in the process of excess calorie burning, thus weight loss. MCTs are also seen as promoting fat oxidation and reduced food intake. Interest in MCTs has been expressed by endurance athletes and the bodybuilding community. While health benefits from MCTs seem to occur, a link to improved exercise performance is weak. A number of studies back the use of MCT oil as a weight loss supplement, but these claims are not without conflict, as about an equal number found inconclusive results.

Medical relevance

MCTs passively diffuse from the GI tract to the portal system (longer fatty acids are absorbed into the lymphatic system) without requirement for modification like long-chain fatty acids or very-long-chain fatty acids. In addition, MCTs do not require bile salts for digestion. Patients who have malnutrition, malabsorption or particular fatty-acid metabolism disorders are treated with MCTs because MCTs do not require energy for absorption, use, or storage.

Medium-chain triglycerides are generally considered a good biologically inert source of energy that the human body finds reasonably easy to metabolize. They have potentially beneficial attributes in protein metabolism, but may be contraindicated in some situations due to a reported tendency to induce ketogenesis and metabolic acidosis. However, there is other authority reporting no risk of ketoacidosis or ketonemia with MCTs at levels associated with normal consumption.

Due to their ability to be absorbed rapidly by the body, medium-chain triglycerides have found use in the treatment of a variety of malabsorption ailments. MCT supplementation with a low-fat diet has been described as the cornerstone of treatment for Waldmann disease. MCTs are an ingredient in some specialised parenteral nutritional emulsions in some countries (not USA). Studies have also shown promising results for epilepsy through the use of ketogenic dieting. Select studies have shown promising results for neurodegenerative disorders (e.g. Alzheimer's and Parkinson's diseases) but clinical effectiveness is not yet established.

Technical uses

MCTs are bland compared to other fats and do not generate off-notes (dissonant tastes) as quickly as LCTs. They are also more polar than LCTs. Because of these attributes, they are widely used as solvents for flavours and oral medicines and vitamins.

See also

• List of saturated fatty acids
• List of carboxylic acids

Further reading

• Medium chain triglycerides - Monograph.