Supplementation of medium-chain triglycerides combined with docosahexaenoic acid improves cognitive function in Chinese older adults with mild cognitive impairment: A randomized double-blind, placebo-controlled trial

Background: Medium-chain triglycerides (MCT) and docosahexaenoic acid (DHA) could affect cognitive function, but their combination effects remain unclear. This randomized, double-blind, placebo-controlled trial aimed to evaluate effects of MCT and DHA supplementation, alone or in combination, on mild cognitive impairment (MCI) patients. Methods: A total of 280 MCI participants were randomly assigned to the placebo group, MCT group (14 g/ d octanoic acid+10 g/d capric acid), DHA group (800 mg/d) and MCT + DHA (14 g/d octanoic acid, 10 g/ d capric acid and 800 mg/d DHA) group, 70 individuals per group for 12 months. Cognitive function was assessed at baseline, 6 months and 12 months; blood indicators were analyzed at baseline and 12 months. This study is registered with Chinese Clinical Trial Registry (ChiCTR2200059641). Results: After 12 months intervention, compared with the placebo group, MCT group, DHA group and MCT + DHA group had statistically significant improvements in full scale IQ ((I: 0.107, 95 % CI: 0.006, 0.208; (I: 0.135, 95 % CI: 0.034, 0.235; (I: 0.136, 95 % CI: 0.035, 0.237), serum total ketone body levels ((I: 10.540, 95 % CI: 9.550, 11.531; (I: 5.884, 95 % CI: 4.894, 6.875; (I: 13.186, 95 % CI: 12.196, 14.176), and decreases in mtDNA deletions ((I: -0.370, 95 % CI: -0.648, -0.092; (I: -0.335, 95 % CI: -0.613, -0.056; (I: -0.427, 95 % CI: -0.705, -0.148) and plasma A(342 levels ((I: -3.318, 95 % CI: -5.571, -1.064; (I: -3.218, 95 % CI: -5.472, -0.965; (I: -2.906, 95 % CI: -5.160, -0.653).