Fats varying in fatty acid chain lengths are metabolized differently. Medium-chain triglycerides (MCT)(1) containing 6–12 carbon fatty acids, differ from long-chain triglycerides (LCT), which have fatty acids of > 12 carbons, in that they are absorbed directly into the portal circulation and transported to the liver for rapid oxidation.(2)
Usual dietary fats are long-chain triglycerides. The following foods are the richest sources of medium-chain triglycerides, including lauric acid, and listed along with their percentage composition of MCTs:
- coconut oil: 55%
- palm kernel oil: 54%
- butter: 8%
MCT oils are generally made by processing coconut and palm kernel oils in the laboratory.
Potential Health Benefits
Some people take MCTs by mouth along with usual medications for treating food absorption disorders including diarrhea, steatorrhea (fat indigestion), celiac disease, liver disease, and digestion problems due to partial surgical removal of the stomach (gastrectomy) or the intestine (short bowel syndrome).
MCTs may also help lower blood sugar levels. In one study, diets rich in MCTs increased insulin sensitivity in adults with type 2 diabetes.(3) In addition, MCTs produce ketones, which act as an alternative energy source for the brain and can thus improve brain function in people following very low-carb diets. Recently, there has been more interest in the use of MCTs to treat or prevent brain disorders like Alzheimer’s disease and dementia.(4)
Athletes sometimes take MCTs by mouth for nutritional support during training, to increase exercise performance, for decreasing body fat and increasing lean muscle mass, and for weight loss.
Dosage, safety, and side effects
MCT oil appears to be safe for most people.
It’s not clear what dose is needed to obtain potential health benefits, but many supplement labels suggest 1–3 tablespoons daily.
There are currently no reported adverse interactions with medications or other serious side effects. However, some minor side effects have been reported, including nausea, vomiting, diarrhea, and an upset stomach. These can be avoided by starting with small doses, such as 1 teaspoon, and increasing intake slowly. Once tolerated, MCT oil can be taken by the tablespoon.
Medium-chain triglycerides have many potential health benefits. While they are not a ticket to dramatic weight loss, they may provide a modest benefit. The same can be said for their role in endurance exercise. For these reasons, adding MCT oil to your diet may be worth a try.
1 Babayan, V. K. (1987) Medium-chain triglycerides and structured lipids. Lipids 22:417–420
2 Scalfi, L, Coltorti, A. & Contaldo, F. (1991) Postprandial thermogenesis in lean and obese subjects after meals supplemented with medium-chain and long-chain triglycerides. Am. J. Clin. Nutr. 53:1130–1133
3 Eckel, R.H., Hanson, A.S. et al (1992). Dietary substitution of medium-chain triglycerides improves insulin-mediated glucose metabolism in NIDDM subjects. Diabetes. 1992 May;41(5):641-7
4 Cunnane, S.C., Courchesne-Loyer A, et al. (2016) Dietary substitution of medium-chain triglycerides improves insulin-mediated glucose metabolism in NIDDM subjects. Ann N Y Acad Sci. 1367(1):12-20