Medium chain triglycerides (MCT) are composed of a glycerol backbone joined to saturated fatty acids of between 8 and 10 carbons long. Because MCTs are readily oxidised by the liver as a fuel source, there is less potential for them to be stored as body fat. During weight loss, consumption of MCTs in place of the longer chain dietary saturated triglycerides (typically C16 and C18), may be beneficial. In addition, studies conducted on both animals and humans have reported that consumption of MCTs causes an increase in the satiating effects of a meal, suggesting that MCT have appetite regulatory effects. Medium chain triglycerides may therefore be beneficial in weight loss because they increase metabolic rate and cause satiety. As well as these benefits, MCT may also lower the traditional risk factors for cardiovascular disease, and this may be as a result of their weight loss properties.
For example, reserchers1 have used a randomised placebo-controlled trial to investigate the metabolic effects of feeding 31 over weight men and women (body mass index 27 to 33 kg/m2) ~12% of energy intake as MCTs or as an olive oil control (figure 1). Consumption of the both diets caused a reduction in fasting glucose and total cholesterol concentrations and there was also a significant drop in the diastolic blood pressure. At the beginning of the trial, 2 of the MCT oil treatment group were diagnosed as suffering from metabolic syndrome, but by the end of the trial this had reversed. In contrast, 1 of the subjects in the olive oil group developed metabolic syndrome during the trial, whereas 4 subjects had no change, and 1 improved. These results suggest that MCT consumption may cause beneficial cardioprotective effects over one containing olive oil.
Figure 1. Fatty acid composition of medium chain triglycerides and olive oil per 100g oil.
Consumption of the mainly C8 and C10 fatty acids present in MCT may therefore improve the metabolic abnormalities associated with metabolic syndrome. The weight loss programme that consisted of a 1500kcal/d or 1800kcal/d diet for the women and men, respectively, caused all the subjects to lose weight. However, those in the MCT group lost more weight than those in the olive oil placebo group. This supports previous data that shows that MCTs may increase weight loss when incorporated in a reduced calorie diet. Weight gain is a risk factor for cardiovascular disease, and so reductions in weight would be expected to reduce the risk of developing the disease. Because weight loss was greater in the MCT group, it would be expected that cardiovascular risk factors would improve the most in this group. Medium chain triglycerides may therefore decrease risk of cardiovascular disease because they induce weight loss.
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