Background: Medium chain triglyceride (MCT) oil is a synthetic oil made from medium chain C8 and C10 fatty acids. It has been traditionally used as a neutral “placebo” in lipid clinical trials. Thus, we had selected MCT oil capsules as a placebo, intended for comparison with an omega-3 polyunsaturated fatty acid containing supplement, to measure fatty acid profiles and inflammation in healthy people.
Methods: The trial was a double-blinded, randomized, placebo controlled trial with cross-over, 4 weeks each study arm. Using serum, the fatty acids were measured and analysed by FAME analysis. HDL and LDL cholesterol profiles and C-reactive protein as a measure of inflammation were also quantified. Blood samples were collected at each time point, and participants assessed for serum lipid profiles.
Results: The outcomes of interest were taken from the differences between measures for each phase of the trial. There were no significant changes in HDL or LDL cholesterol in this time, and CRP also showed no significant changes. However, levels of the fatty acids eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) showed significant decreases after MCT supplementation.
Conclusion: These results revealed an unexpectedly adverse effect of the MCT oil. Such comparisons raise questions about the use of MCT oil as a placebo, as it was not neutral in its effect on blood lipid biomarkers. The results have ramifications for claims made about the positive benefits of MCT oils.
Lynnette R Ferguson, Bobbi Laing, Stephanie Ellett, Gareth Marlow, Amalini Jesuthasan, Nishi Karunasinghe and Laurence Eyres