HMB, or beta-hydroxy-beta-methylbutyrate, is a metabolite of the amino acid leucine and has been widely studied for its effects on bolstering muscle synthesis and preventing muscle fiber breakdown. Ralf Jaeger, PhD, a sports nutritionist and fellow of the International Society of Sports Nutrition who has studied HMB in his own right, said that like a number of other ingredients coming out of the sports nutrition arena that target muscle growth, HMB has been increasingly studied in a healthy aging, sarcopenia-targeting setting.
“HMB was actually ahead of the curve in comparison to other sports nutrition ingredients, as it has been studied in non-athletic population already more than 15 years ago,” Jaeger told NutraIngredients-USA.
“HMB has been shown to reduce muscle atrophy during bedrest (-92% compared to control) and aid subsequent muscle gains during rehabilitation (Source: N.E. Deutz et al. Clin Nutr. 2013, 32(5):704-712). HMB (in combination with Arginine and Glutamine) has been shown to restore lean body mass in cachexia due to cancer (L. Berk et al. Support Care Cancer 2008, 16:1179-1188), rheumatoid arthritis (S. Marcora et al. Clin Nutr 2005, 24:442-454), AIDS (R.H. Clark et al. J Parenter Enteral Nutr 2000, 24:133-139), and in critically ill trauma patients,” Jaeger added.
The paper, published in the journal Clinical Nutrition, was a report on the NOURISH study (Nutrition effect On Unplanned ReadmIssions and Survival in Hospitalized patients), which was supported by Abbott Nutrition. The study was a multicenter, randomized, placebo controlled parallel-group study conducted in the United States between May 2012 and October 2014. The study evaluated the effects of a nutritional formulation that inlcuded high protein, HMB, and vitamin D on the postdischarge incidence of hospital readmission, nutritional status indices and morbid events in older hospitalized adults. Following from the initial protocol, the incidence of nonelective readmission within 90 days postdischarge was the primary outcome.
The results showed that the HP-HMB formulation did not significantly alter the rate at which patients were readmitted during the study window compared to placebo. The formula did, however, decrease overall mortlity during the 90-day period and also improved indicies of nutritional status.
Jaeger noted that the selective nature of the study group could be a confounding factor in the results. Similarly, the used of a blend of ingredients clouds the picture for applicability of the results to HMB itself.
“In contrast to previous studies with oral nutritional supplements, this study showed no effect on readmission. Potential reasons include the higher mortality rate in the control group resulting in patients dying without a prior readmission, length of the follow-up or competing events,” Jaeger said.
”The study investigated the effects of nutrient dense nutritional supplement, containing 20g of protein, 1.5g of HMB and 160 IU of Vitamin D in comparison to a low caloric (48 kcal) supplement containing 12 g carbohydrate, and 10 mg vitamin C with no further micro nutrients as control. The observed beneficial effects cannot be attributed to a single active ingredient (protein, or HMB or vitamin D), as several bioactive ingredients have been co-administered,” he added.
Solid overall backing
But Jaeger said that the overall backing for HMB is very solid, leading the ISSN to publish a favorable position stand in the ingredient in 2013. Jaeger also noted that the ingredient has shown additive, synergistic benefits in combination with other ingredients such as creatine or ATP.
“While HMB improves overall muscle balance by increasing muscle protein synthesis and decreasing muscle breakdown, studies suggest HMB is especially effective during times of increased stress to the muscle such overtraining, atrophy, or cachexia. Combinations with nutritional ingredients known to aid muscle health, such as vitamin D, or additionally stimulate muscle protein synthesis, such as leucine (protein) or phosphatidic acid, could provide additional benefits,” Jaeger said.
Source: Clinical Nutrition
“Readmission and mortality in malnourished, older, hospitalized adults treated with a specialized oral nutritional supplement: A randomized clinical trial”
pii: S0261-5614(15)00348-9. doi: 10.1016/j.clnu.2015.12.010. [Epub ahead of print]
Authors: Deutz NE et al.