Superior bioavailability of the calcium salt form of ß-hydroxy-ß-methylbutyrate compared with the free acid form.

We investigated the bioavailability of the calcium salt (HMB-Ca) and the free acid (HMB-FA) forms of ß-hydroxy-ß-methylbutyrate (HMB). Sixteen young individuals received the following treatments on three different occasions in a counterbalanced crossover fashion: (1) HMB-FA in clear capsules; (2) HMB-Ca in gelatine capsules; (3) HMB-Ca dissolved in water. All treatments provided 1 g of HMB. Blood samples were taken before and on multiple time points following ingestion. The following parameters were calculated: peak plasma (Cmax), time to peak (Tmax), slope of HMB appearance in blood, area under the curve (AUC), half-life time (t1/2) and relative bioavailability (HMB-Ca in water set as reference). All treatments led to rapid and large increases in plasma HMB. HMB-Ca in capsules and in water showed similar plasma HMB values across time (p = 0.438). HMB-FA resulted in lower concentrations vs. the other treatments (both p < 0.001). AUC (HMB-Ca in capsules: 50,078 ± 10,507; HMB-Ca in water: 47,871 ± 10,783; HMB-FA: 29,130 ± 12,946 µmol L-1 × 720 min), Cmax (HMB-Ca in capsules: 229.2 ± 65.9; HMB-Ca in water: 249.7 ± 49.7; HMB-FA: 139.1 ± 67.2 µmol L-1) and relative bioavailability (HMB-Ca in capsules: 104.8 ± 14.9%; HMB-FA: 61.5 ± 17.0%) were lower in HMB-FA vs. HMB-Ca (all p < 0.001). HMB-Ca in water resulted in the fastest Tmax (43 ± 22 min) compared to HMB-Ca in capsules (79 ± 40 min) and HMB-FA (78 ± 21 min) (all p < 0.05), while t1/2 was similar between treatments. To conclude, HMB-Ca exhibited superior bioavailability compared to HMB-FA, with HMB-Ca in water showing faster absorption. Elimination kinetics were similar across all forms, suggesting that the pharmaceutical form of HMB affects the absorption rates, but not its distribution or elimination.

Genetics and sport performance: current challenges and directions to the future

In recent years there has been a great progress in molecular biology techniques, which has facilitated the researches on influence of genetics on human performance. There are specific regions of DNA that can vary between individuals. Such variations (i.e., polymorphisms) may, in part, explain why some individuals have differentiated responses to certain stimuli, including the responses to sports training. In a particular sport, the presence of specific polymorphisms may contribute to high levels of performance. Since 1998, several polymorphisms have been associated with athletic phenotypes; however the accumulation of information generated over these 15 years shows that the influence of genetics to sport is extremely complex. In this review, we will summarise the current status of the field, discussing the implications of available knowledge for the practice of professionals involved with the sport and suggesting future directions for research. We also discuss topics related to the importance of polygenic profile characterization of athletes, methods for the identification of new polymorphisms associated with physical performance, the use of genetic testing for predicting competitive success, and how crucial is the genetic profile for the success athletes in competition.