Dose-response of beta-hydroxy beta-methyl butyrate supplementation (HMB -FA) on muscle and liver damage indices induced by an eccentric resistance exercise session in non-athlete females

Start or continuation of physical activity can especially be a challenge for non-athletes due to exercise-induced muscle injuries. Therefore, the purpose of this study was to investigate the dose-dependent effects of beta-hydroxy beta-methyl butyrate (HMB -FA) on muscle and liver damage indices induced by high-intensity eccentric resistance exercise in non-athlete girls.

24 non-athlete girls (age= 25.87±1.65 years, BMI=20.97±1.36) selected from volunteers to participate in this study. Participants were randomly divided into three HMB-FA supplementation groups (n=8) with doses of (HMB-1.5) 1.5, (HMB-3) 3, and (HMB-4) 4 g/d. After six days of supplementation, an eccentric resistance session with a maximum intensity of 120% was carried out. Blood and urine samples were collected in 4 stages including before supplementation, before exercise, immediately, and 24 hours after exercise. For comparison of the results, 3×4 variance analysis was used.

The results showed that different doses of supplementation had no significant effect on blood levels of AST and ALT as well as urine levels of creatinine and urea. However, LDH and CK levels showed significant inter and intragroup differences(p<0.05). Results showed that values of CK and LDH between HMB-1.5 and other groups had significant differences at 24h post-exercise session.

Considering significant differences in enzymatic indices of CK and LDH between 1.5g/d supplementation with 3 and 4 g/d doses, we conclude that 1.5g/d dose should not be considered as an inhibitor of high-intensity exercise-induced muscle damage. Also since 3 and 4 g/d showed no differences in inhibiting muscle and liver damage indices in blood and urine, the lower dose (3g/d) can be our prescription as the optimal dose.