A year-long randomised, double-blind, placebo-controlled study indicates that the combination of HMB and vitamin D3 improves muscle function in older adults, even without exercise. The study was supported by a grant from the National Institutes of Health and published in The Journals of Gerontology.
Larry Kolb, president of TSI USA (TSI) said: “It is unrealistic to simply increase dietary protein because as we age, we begin to lose our ability to respond to certain signals such as how our body responds to ingesting protein or to exercise. As a result, we need more protein or exercise to achieve the same muscle growth responses.”
HMB stimulates protein synthesis and reduces muscle breakdown while higher vitamin D3 levels are associated with greater strength and superior muscle function, especially in older adults.
The most exciting thing about this study is that with HMB+D, there was a significant improvement in muscle function in the non-exercise group specifically
“With this study, we now understand HMB and vitamin D3 can have a synergistic effect in older adults, superior to what either can do individually,” said principal investigator John Rathmacher, PhD.
A previous year-long, placebo-controlled study of HMB found it increased lean body mass in adults over age 65 but didn’t appear to improve strength. Because 70% of those study participants had insufficient vitamin D levels, researchers performed a retrospective analysis and found that only those who had sufficient vitamin D3 levels saw an increase in strength with HMB.
In the recently published study, 117 healthy adults ages 60 and older were assigned to take HMB and a vitamin D3 or a placebo supplement. In each group, half of the subjects participated in a mild resistance training program, while the other half did not exercise. The exercise consisted of 60 minute supervised progressive resistance training sessions, three days a week. Researchers measured physical function, muscle strength and body composition at three-month intervals.
The results indicated that HMB’s long-term functional benefits are fully realized among older adults when there is sufficient vitamin D3 present.
Among non-exercisers, participants taking HMB+D experienced greater improvements in physical function and tended to have greater increases in strength than did participants taking the placebo supplement, and they sustained this improvement over one year.
Combining HMB+D and moderate resistance training did not provide any further benefit over either exercise or HMB+D alone. “This indicates that HMB+D may uniquely protect muscle strength and physical function in those who are unable or unwilling to exercise such as older adults who are frail or have age-related muscle loss”.
“The most exciting thing about this study is that with HMB+D, there was a significant improvement in muscle function in the non-exercise group specifically," concluded Rathmacher.
Kolb concluded: “Results of this study indicate that adding vitamin D3 to daily HMB supplementation yields the full benefits of HMB. And older adults who have a higher functional muscle reserve will be more resistant to the numerous quality of life issues associated with age-related muscle loss.”