HMB — can an unassuming powder protect older adults from muscle loss?

Aim of the study: Beta-hydroxy-beta-methylbutyrate (HMB), a metabolite of the branched-chain amino acid leucine, has been investigated as a potential supplement to improve muscle quality; however, whether HMB supplementation has beneficial effects on muscle loss in older adults remains unclear.

Results: A total of seven randomized controlled trials were included, in which 147 older adults received HMB intervention and 140 were assigned to control groups. The meta-analysis showed greater muscle mass gain in the intervention groups compared with the control groups (standard mean difference=0.352kg; 95% confidence interval: 0.11, 0.594; Z value=2.85; P=0.004). There were no significant fat mass changes between intervention and control groups (standard mean difference=-0.08kg; 95% confidence interval: -0.32, 0.159; Z value=0.66; P=0.511). Beta-hydroxy-beta-methylbutyrate supplementation contributed to preservation of muscle mass in older adults. HMB supplementation may be useful in the prevention of muscle atrophy induced by bed rest or other factors. Further studies are needed to determine the precise effects of HMB on muscle strength and physical function in older adults.

Aim of the study: Beta-hydroxy beta-methylbutyrate (HMB), a metabolite of leucine, is currently widely used in athletes to increase muscle mass and strength and has also been used as a nutritional supplement in recent years to maintain muscle mass in muscular atrophic diseases of older people. However, the effects of HMB supplementation on muscle mass, muscle strength, and physical function in older people remain controversial.

Results: A total of 9 studies (448 participants) were eventually found eligible. The pooled results showed that HMB supplementation significantly increased fat-free mass in older people compared with the control group (effect size: 0.37; 95% Cl 0.16, 0.58; Z value = 3.47, P = 0.001; Fixed-effect model). But it had no effect on fat mass (effect size: - 0.04 95% CI - 0.26, 0.18; Z value = 0.36, P = 0.716, fixed-effect model). Subgroup analysis of HMB supplementation alone showed a significant improvement in fat-free mass in older people (effect size: 0.59; 95% CI 0.32, 0.87; Z = 4.24, P < 0.001; fixed-effect model), whereas HMB supplementation combined with exercise intervention showed no additional fat-free mass change (effect size: 0.06; 95% CI - 0.26, 0.38; Z = 0.38, P = 0.705; Fixed-effect model). HMB supplementation is beneficial for improving body composition in older people. However, the effect of HMB supplementation combined with exercise therapy to improve muscle mass is not obvious.

Aim of the study: Sarcopenia is recognized as a major public health concern because of its association with several adverse health events. Beta-hydroxy-beta-methylbutyrate (HMB) supplementation reportedly delays the loss of muscle mass and function; however, the effect of HMB on sarcopenia remains inconclusive.

Results: After the 12-week intervention, the HMBG demonstrated significantly greater improvements in handgrip strength (4.61(95%CI:2.93,6.28) kg, P<0.001), gait speed (0.11(95%CI:0.02,0.20)m/s, P=0.014), five-time chair stand test (-3.65 (95%CI:-5.72, -1.58)s, P=0.001), muscle quality (2.47(95%CI:1.15,3.80),kg.kg-1 P=0.001) and tumor necrosis factor-like weak inducer of apoptosis (-15.23(95%CI:-29.80,-0.66)pmol/mL, P=0.041) compared with the PG; no significant differences in skeletal muscle mass, skeletal muscle index, and other body composition parameters were found between the two groups. In older adults with sarcopenia, HMB significantly enhance the effect of resistance exercise training on muscle strength, physical performance, muscle quality, and reduced inflammatory factors. Therefore, HMB supplementation could be an effective treatment for sarcorpenia. The trial protocol was registered at http://www.chictr.org.cn/showproj.aspx?proj=47571 as ChiCTR2000028778.

Aim of the study: to examine the clinical evidence reporting the prevalence of sarcopenia and the effect of nutrition and exercise interventions from studies using the consensus definition of sarcopenia proposed by the European Working Group on Sarcopenia in Older People (EWGSOP).

Results: prevalence of sarcopenia was, with regional and age-related variations, 1-29% in community-dwelling populations, 14-33% in long-term care populations and 10% in the only acute hospital-care population examined. Moderate quality evidence suggests that exercise interventions improve muscle strength and physical performance. The results of nutrition interventions are equivocal due to the low number of studies and heterogeneous study design. Essential amino acid (EAA) supplements, including ∼2.5 g of leucine, and β-hydroxy β-methylbutyric acid (HMB) supplements, show some effects in improving muscle mass and function parameters. Protein supplements have not shown consistent benefits on muscle mass and function. prevalence of sarcopenia is substantial in most geriatric settings. Well-designed, standardised studies evaluating exercise or nutrition interventions are needed before treatment guidelines can be developed.

Aim of the study: To document recent evidence regarding the role of nutrition as an intervention for sarcopenia.

Results: A review of seven randomized controlled trials (RCTs) on beta-hydroxy-beta-methylbutyrate (HMB) alone on muscle loss in 147 adults showed greater muscle mass gain in the intervention group, but no benefit in muscle strength and physical performance measures. Three other review articles examined nutrition and exercise as combined intervention, and suggest enhancement of benefits of exercise by nutrition supplements (energy, protein, vitamin D). Four trials reported on nutrition alone as intervention, mainly consisting of whey protein, leucine, HMB and vitamin D, with variable results on muscle mass and function. Four trials examined the combined effects of nutrition combined with exercise, showing improvements in muscle mass and function.