HMB (beta-hydroxy beta-methylbutyrate), a metabolite of the amino acid leucine, has long been popular for strength and recovery benefits among competitive athletes. A new trial, funded by the National Institutes of Health and published in the Journal of Gerontology, concluded that this compound administered in combination with vitamin D was able to preserve muscle function in older adults, even if they were unable to exercise, signifying a potential solution for inevitable and involuntary age-related muscle loss, which affects 100% of the population.
 
The trial, which lasted a year, enrolled 117 healthy adults over the age of 60, who were divided into two groups based upon whether they exercised or did not. Both groups were administered a daily dose of HMB and vitamin D3, which was able to improve muscle function in both groups.
 
“There is a large population who either know they need to exercise to maintain their muscle mass but don’t do it, or, they don’t do it to a sufficient level to maintain muscle health,” Larry Kolb, president of TSI USA, which produces the branded ingredient myHMB, said. “Others, especially among the older population, may be too frail or have other limitations prohibiting exercise. 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.”
 
In a previous study on HMB, it was observed that HMB increased lean body mass in adults over the age of 65, however, no improvements to strength were made, the authors of this study said. 70% of the participants in that previous trial had insufficient vitamin D levels, and a retrospective analysis that the current researchers performed found that only those who had sufficient vitamin D3 levels experienced an increase in strength during that trial.
 
“That led to the hypothesis that it is important for older adults to have an adequate vitamin D3 status when supplementing with HMB,” principal investigator John Rathmacher, PhD, said. “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.”
 
Results
 
With sufficient intake of vitamin D3, non-exercisers enrolled in the trial who took HMB and vitamin D experienced greater improvements in physical function and tended to have greater increases in strength than participants taking a placebo supplement, and they sustained this improvement over one year. While HMB generally had greater effects upon those who were able to practice resistance training, exercise was not needed to realize the protective effects of supplementation, which was the most notable result for this supplement. “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,” Rathmacher said. “I am unaware of any other nutrient capable of doing this.”
 
Improvements were observed over the 12-month trial through measurements of body composition, strength, functionality, and questionnaires.
 
A secondary benefit observed in the clinical trial involved greater self-perceptions of energy, the authors of the study said.