The effects of medium chain triglyceride consumption on cardiometabolic markers: a systematic literature review

Medium chain triglycerides (MCT) are composed of saturated fatty acids with a six to twelve carbon atoms in a chain and their metabolism differs from that of long-chain triglycerides. MCT are directly absorbed into the portal circulation and once they reach the liver they are rapidly beta-oxidised in the mitochondria for energy or synthesised into ketone bodies. The consumption of MCT can also influence body weight, cardiometabolic health and the circulating lipid profile. The aim of this systematic literature review was to evaluate the current evidence of controlled trials investigating the effects of MCT consumption on cardiometabolic markers.
Following PRISMA 2009 guidelines, literature searches were conducted across five electronic databases (Scopus, PubMed, CINAHL, Cochrane, Web of Science) until February 2021. The primary outcomes were cardiometabolic markers, including circulating lipid profile, while secondary outcomes included body composition, blood pressure, blood glucose and insulin.
In total, 2,123 articles were screened, and thirteen studies met the inclusion criteria with a treatment duration between 3-16 weeks. Intake of MCT varied between 9-60 g/day, and the purity of MCT within the supplements was 85% (w/w) and greater. At the end of the treatment, higher values in the MCT group vs control were reported for total cholesterol (nstudies=4; 1.5 – 11%), triglycerides (nstudies=3; 1.75 – 22%) and blood glucose (nstudies=1; 11%). Four studies reported decrease in total cholesterol at the end of the treatment for both MCT and control groups (ΔMCT; 0.61 - 1.93; ΔControl; 0.3 – 1.88 mmol/L) while two studies reported decreases in triglycerides (ΔMCT; 0.3 – 0.5; ΔControl; 0.2 – 0.5 mmol/L). Six studies reported no changes in circulating lipid profiles, blood glucose and insulin profiles, while one study reported a decrease in participants exhibiting metabolic syndrome following MTC supplementation. Five studies reported weight loss in the MCT group (Δ -1.6 – 9.7kg) mainly due to fat mass loss (All P’s<0.05).
There is no consensus for the use of MCT in the management of cardiometabolic markers. While some metabolic benefits may exist, dose-response studies and longer trials are required to evaluate the effects of MCT on cardiometabolic health.