Trigliceridi a media catena in combinazione alla leucina e alla vitamina D, in uno studio randomizzato controllato, aumentano la forza e la funzione muscolare negli anziani fragili

S. Abe, O. Ezaki and M. Suzuki

J Nutr. 2016;146(5):1017-26

Sarcopenia, the loss of skeletal muscle mass, strength, and function, is common in elderly individuals but difficult to treat.

38 elderly nursing home residents (11 men and 27 women with a mean ± SD age of 86.6 ± 4.8 y) in a 3 months randomized, controlled, single-blind, parallel group trial were enrolled. The participants were randomly allocated to 3 groups. The first group received a daily l-leucine (1.2 g) and cholecalciferol (20 μg)-enriched supplement with 6 g medium-chain triglycerides (TGs) (MCTs) (LD + MCT); the second group received the same leucine and cholecalciferol-enriched supplement with 6 g long-chain TGs (LD + LCT); and the third group did not receive any supplements (control). The supplement and oils were taken at dinner, and changes in muscle mass, strength, and function were monitored.

The increase in body weight in the LD + MCT (1.1 ± 1.0 kg) and LD + LCT (0.8 ± 1.1 kg) groups was greater than that in the control group (-0.5 ± 0.9 kg) (P < 0.05). After 3 months, participants in the LD + MCT group had a 13.1% increase in right-hand grip strength (1.2 ± 1.0 kg, P < 0.01), a 12.5% increase in walking speed (0.078 ± 0.080 m/s, P < 0.05), a 68.2% increase in a 10-s leg open-and-close test performance (2.31 ± 1.68 n/10 s, P < 0.001), and a 28.2% increase in peak expiratory flow (53 ± 59 L/min, P < 0.01). No significant improvements in muscle mass, strength, or function were observed in the LD + LCT or control groups.

Comment: The combined supplementation of MCTs (6 g), leucine-rich amino acids, and cholecalciferol at dinner may improve muscle strength and function in frail elderly individuals. Although this combination of several nutrients showed promise in the very frail elderly participants in this study, it is not clear whether similar favorable effects would be observed with MCTs only or the combination of 2 nutrients including MCTs, or in other frail populations. Further studies are required to clarify these issues.