Daily supplements containing HMB, a metabolite of the branched chain amino acid leucine, may preserve muscle mass during bed rest, says a new study by Abbott Nutrition.
Results of a randomized, controlled, double-blind trial found that a daily dose of HMB (beta-hydroxy-beta-methylbutyrate) of 3 grams prevented declines in lean body mass in healthy older adults during 10 days of complete bed rest.
On the other hand, the placebo group experienced significant muscle loss, report researchers from the University of Arkansas for Medical Sciences and Abbott Nutrition in Clinical Nutrition .
It is well known that bed rest leads to significant loss of muscle, and healthy older adults are said to lose about 6% of their muscle tissue in the lower extremities after 10 days of bed rest. In addition, “this dramatic loss of muscle mass and strength is greater than is observed in young adults after 14 or 28 days of bed rest,” explained the researchers, led by Nicolaas Deutz from the University of Arkansas.
In order to test the effects of HMB supplementation in older people, Deutz and his co-workers recruited 24 people with an average age of 67 confined to complete bed rest for ten days. After this time, all the participants underwent a resistance training regime for eight weeks.
Participants were randomly assigned to either a placebo group or to receive two HMB sachets per day containing contained 1.5 g Ca-HMB (TSI, Salt Lake city, Utah), 4 g maltodextrin, and 200 mg calcium. The supplements were started five days prior to bed rest and continued for the full 10 days of bed rest.
Results showed that the control group lost an average of 2 kg of lean body mass after 10 days of complete. HMB supplements, however, were found to prevent this decline, said the researchers.
“Our current study shows that HMB is an effective nutritional intervention for preservation of muscle mass in healthy older adults confined to bed rest. It may be that a greater availability of EAAs was required than we provided, by using the RDA as a guideline for protein intake, for a stimulatory effect of HMB on muscle [fractional synthesis rate of muscle protein] to reach statistical significance.
“HMB was able to prevent the acute decline in muscle mass in older adults over 10 days of bed rest and this will most likely translate into maintenance of muscle strength/function during extended immobilization,” they concluded.
ISSN position paper
The International Society of Sports Nutrition recently published a position paper on HMB in Journal of the International Society of Sports Nutrition as a nutritional supplement.
For more information, please click here .
Source: Clinical Nutrition
Published online ahead of print, doi: 10.1016/j.clnu.2013.02.011
“Effect of β-hydroxy-β-methylbutyrate (HMB) on lean body mass during 10 days of bed rest in older adults”
Authors: N.E.P. Deutz, S.L. Pereira, N.P. Hays, J.S. Oliver, N.K. Edens, C.M. Evans, R.R. Wolfe