Free acid gel form of β-hydroxy β- Methylbutyrate (HMB) improves HMB clearance from plasma in human subjects compared with the calcium HMB salt

Abstract

The leucine metabolite, β-hydroxy β- methylbutyrate (HMB), is a nutritional supplement that increases lean muscle and strength with exercise and in disease states. HMB is presently available as the Ca salt (CaHMB). The present study was designed to examine whether HMB in free acid gel form will improve HMB availability to tissues. Two studies were conducted and in each study four males and four females were given three treatments in a randomised, cross-over design. Treatments were CaHMB (gelatin capsule, 1g), equivalent HMB free acid gel swallowed (FASW) and free acid gel held sublingual for 15s then swallowed (FASL). Plasma HMB was measured for 3h following treatment in study 1 and 24h with urine collection in study 2. In both the studies, the times to peak plasma HMB were 128 (sem 11), 38 (sem 4) and 38 (sem 1)min (P<00001) for CaHMB, FASW and FASL, respectively. The peak concentrations were 131 (sem 6), 249 (sem 14) and 239 (sem 14)mol/l (P<00001) for CaHMB, FASW and FASL, respectively. The areas under the curve were almost double for FASW and FASL (P<00001). Daily urinary HMB excretion was not significantly increased resulting in more HMB retained (P<0003) with FASW and FASL. Half-lives were 317 (sem 022), 250 (sem 013) and 251 (sem 014)h for CaHMB, FASW and FASL, respectively (P<0004). Free acid gel resulted in quicker and greater plasma concentrations (+185%) and improved clearance (+25%) of HMB from plasma. In conclusion, HMB free acid gel could improve HMB availability and efficacy to tissues in health and disease. © 2010 The Authors.