Supplementation with 6 g/day of medium-chain triglycerides (MCTs) at dinnertime increases muscle function and cognition in frail elderly adults relative to supplementation with long-chain triglycerides. However, suitable timing of MCT supplementation during the day is unknown.

We enrolled 40 elderly nursing home residents (85.9 ± 7.7 years) in a 1.5-month randomized intervention trial. Participants were randomly allocated to two groups: one received 6 g/day of MCTs at breakfast (breakfast group) as a test group and the other at dinnertime (dinner group) as a positive control group.

Muscle mass, strength, function, and cognition were monitored at baseline and 1.5 months after initiation of intervention. RESULTS: Thirty-seven participants completed the study and were included in the analysis. MCT supplementation in breakfast and dinner groups respectively increased right arm muscle area from baseline by 1.1 ± 0.8 cm² (P<0.001) and 1.6 ± 2.5 cm² (P<0.001), left arm muscle area by 1.1 ± 0.7 cm² (P<0.001) and 0.9 ± 1.0 cm² (P<0.01), right knee extension time by 39 ± 42 s (P<0.01) and 20 ± 32 s (P<0.05), leg open and close test time by 1.74 ± 2.00 n/10 s (P<0.01) and 1.67 ± 2.01 n/10 s (P<0.01), and Mini-Mental State Examination score by 1.5 ± 3.0 points (P=0.06) and 1.0 ± 2.1 points (P=0.06). These increases between two groups did not differ statistically significantly.

Supplementation with 6 g MCTs/day for 1.5 months, irrespective of ingestion at breakfast or dinnertime, could increase muscle mass and function, and cognition in frail elderly adults.