Review of the toxicologic properties of medium-chain triglycerides

Medium chain triglycerides (MCTs) are a family of triglycerides, containing predominantly, caprylic (C8) and capric (C10) fatty acids with lesser amounts of caproic (C6) and lauric (C12) fatty acids. MCTs are widely used for parenteral nutrition in individuals requiring supplemental nutrition and are being more widely used in foods, drugs and cosmetics. MCTs are essentially non-toxic in acute toxicity tests conducted in several species of animals. In ocular and dermal irritation testing MCTs exhibit virtually no potential as ocular or dermal irritants, even with prolonged eye or skin exposure. MCTs exhibit no capacity for induction of hypersensitivity. Ninety-day toxicity tests did not result in notable toxicity, whether the product was administered in the diet up to 9375 mg/kg body weight/day or by intramuscular (im) injection (up to 0.5 ml/kg/day, rabbits). There was no evidence that intravenous (iv) or dietary administration of MCTs adversely affected the reproductive performance of rats or resulted in maternal toxicity, foetal toxicity or teratogenic effects at doses up to 4.28 g/kg body weight/day (iv) or 12,500 mg/kg body weight/day (dietary). There was no evidence that dietary administration of MCTs adversely affected the reproductive performance of pigs or resulted in maternal toxicity, foetal toxicity or teratogenic effects at doses up to 4000 mg/kg body weight/day in the diet. In rabbits, following iv administration, the maternal and foetal no-observed-adverse-effect levels (NOAELs) were between 1.0 and 4.28 g/kg body weight/ day. A 2-year study in rats, conducted with a closely related compound (tricaprylin, a triglyceride with C8 fatty acids), provided no evidence of a carcinogenic effect when the material was administered by oral gavage at levels up to 10 ml/kg (9.54 g/kg) per day. Although tricaprylin was found to be positive in one of five strains of Salmonella typhimurium in the presence of metabolic activation in an Ames mutagenicity assay, the results of the carcinogenicity test with tricaprylin and mutagenicity tests with caprylic acid indicate that MCTs do not have the potential to be carcinogenic or mutagenic. The safety of human dietary consumption of MCTs, up to levels of 1 g/kg, has been confirmed in several clinical trials.