Our abilities to synthesize protein typically decreases as we age and leads to sarcopenia – the loss of muscle mass associated with aging.
While increasing protein intake can counter this, barriers including palatability, cost, satiety and habitual practices can inhibit regular protein intake, explain researchers from the University of Texas Medical Branch and the University of Central Florida.
Low-dose daily supplements of leucine may boost the rate of synthesis of protein after a meal, and provide a way of combating sarcopenia.
“We demonstrated that supplementing regular daily meals with a relatively small amount of leucine improves both mixed muscle protein synthesis and anabolic signaling in older adults,” wrote researchers in the journal Clinical Nutrition.
“Further, while we did not conduct a specific assessment of practical issues such as longer duration compliance, ease of use or palatability, our low-volume approach is intuitively less likely to be burdensome than most traditional higher-volume amino acid supplement regimens.”
Led by Douglas Paddon-Jones, PhD, the researchers recruited eight healthy older people with an average age of 68 and supplemented their meals with leucine at a dose of 12 grams per day for 14 days.
Results showed that leucine supplementation increased the rate of protein synthesis, as well as markers of nutrient signaling.
“Our data suggest that leucine supplementation may be an energetically efficient and practical means of chronically improving muscle protein synthesis in response to a low protein meal in older adults who habitually consume close to the RDA for protein,” wrote Dr Paddon-Jones and his co-workers.
“In the context of preventing or slowing sarcopenic muscle loss, the rationale for the use of a dietary supplement should take into account one or more of the following assumptions:
i) supplementation will improve net muscle protein anabolism above that afforded by regular meals alone,
ii) the supplement will not negatively influence consumption of normal daily meals and
iii) use of the supplement will not be compromised or restricted by a lack of compliance, complex preparation, high cost or poor palatability.”
Source: Clinical Nutrition
Published online ahead of print, doi: 10.1016/j.clnu.2012.01.005
“Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for protein”
Authors: S.L. Casperson, M. Sheffield-Moore, S.J. Hewlings, D. Paddon-Jones