Oral administration of beta-hydroxy beta-methylbutyrate (HMB), a metabolite of leucine, promotes increased lean muscle mass in older adults, according to researchers who conducted a meta-analysis of eight randomized, placebo-controlled trials. The review, published in the journal European Geriatric Medicine, concluded that HMB supplementation is beneficial for improving body composition in older people.
 
Larry Kolb, president of nutraceutical ingredients supplier TSI Group, said that this news supports the growing healthy aging market.
 
“This review is timely given the growing healthy aging market segment. There is a very strong need among consumers and healthcare practitioners for more information on maintaining muscle mass and function in healthy older adults,” Kolb said.
 
The review authors, representing the Department of Geriatric Cardiology, The Second Affiliated Hospital of Chongqing Medical University, said that when compared to resistance training alone, dietary interventions for age-related muscle loss (sarcopenia) appear to be a safe and effective method for alleviating muscle atrophy in older adults with limited mobility or who are at high risk of fall-related injuries. “HMB supplementation is expected to be an important class of these dietary interventions,” they wrote.
 
They evaluated eight articles which covered nine randomized, placebo-controlled human clinical trials involving participants with a mean age of 65. In each of these trials, participants were administered HMB or some combination of substrates with HMB as a primary intervention for no fewer than four weeks, and researchers measured lean mass at baseline and post-intervention.
 
Doses of HMB ranged from 1.5g/day to 3g.day.. Where used, substrates included various combinations of L-arginine, L-glutamine, lysine, ascorbic acid, and a carbohydrate. Four of the nine studies included exercise intervention. While most of the studies’ participants were healthy older adults, one involved older adults diagnosed with stage four cancer, and another involved healthy older adults who had been on bed rest for 10 days, and one described participants as “ambulatory.”
 
Based on the entirety of the evidence evaluated, “The results of the meta-analysis showed that oral HMB supplementation could effectively increase muscle mass, but the change in fat mass was not significant,” the authors concluded. “The increase in muscle mass is due to the net positive balance of protein renewal in the skeletal muscle caused by HMB through stimulation of protein synthesis and attenuation of protein degradation.”