Combined supplementation with medium-chain triglycerides (MCTs), leucine-rich essential amino acids, and vitamin D has been shown to improve muscle function in frail older adults; however, its chronic metabolic effects remain unclear.This study aimed to evaluate the metabolic impacts of this combined supplementation using fasting blood analyses.Frail older adults residing in a long-term care facility (n = 38) received leucine-rich essential amino acids (3 g/day) and vitamin D (20 μg/day), combined with either MCTs (6 g/day), long-chain triglycerides (LCTs), or no supplementation (Control group) for 3 months.Fasting venous blood samples were collected at baseline and after the intervention.Among the parameters examined, only fasting blood glucose showed a significant difference in changes among groups (ANCOVA, P = 0.021), with a greater decrease observed in the Control group, possibly reflecting reduced energy intake rather than a beneficial metabolic effect.Although changes in prealbumin did not reach statistical significance, levels tended to be higher in the MCT group than in the LCT group.These findings suggest that combined supplementation with MCTs may help maintain fasting blood glucose levels during the intervention period and support hepatic protein metabolism in frail older adults without causing clinically relevant abnormalities in fasting blood parameters.
Abe et al. (2026) studied this question.