Essential Amino Acid Ingestion Facilitates Leucine Retention and Attenuates Myofibrillar Protein Breakdown following Bodyweight Resistance Exercise in Young Adults in a Home-Based Setting.

Home-based resistance exercise (RE) has become increasingly prevalent, but its effects on protein metabolism are understudied. We tested the effect of an essential amino acid formulation (EAA+: 9 g EAAs, 3 g leucine) and branched-chain amino acids (BCAAs: 6 g BCAAs, 3 g leucine), relative to a carbohydrate (CHO) placebo, on exogenous leucine retention and myofibrillar protein breakdown following dynamic bodyweight RE in a home-based setting. Twelve recreationally active adults (nine male, three female) participated in a double-blind, placebo-controlled, crossover study with four trial conditions: (i) RE and EAA+ (EX-EAA+); (ii) RE and BCAAs (EX-BCAA); (iii) RE and CHO placebo (EX-CHO); and (iv) rest and CHO placebo (REST-CHO). Total exogenous leucine oxidation and retention (estimates of whole-body anabolism) and urinary 3-methylhistidine:creatinine ratio (3MH:Cr; estimate of muscle catabolism) were assessed over 5 h post-supplement. Total exogenous leucine oxidation and retention in EX-EAA+ and EX-BCAA did not significantly differ (p = 0.116) but were greater than EX-CHO (p < 0.01). There was a main effect of condition on urinary 3MH:Cr (p = 0.034), with post hoc analysis revealing a trend (p = 0.096) for reduced urinary 3MH:Cr with EX-EAA+ (32%) compared to EX-CHO. By direct comparison, urinary 3MH:Cr was significantly lower (23%) in EX-EAA+ than EX-BCAA (p = 0.026). In summary, the ingestion of EAA+ or BCAA provided leucine that was ~60% retained for protein synthesis following home-based bodyweight RE, but EAA+ most effectively attenuated myofibrillar protein breakdown.

Effect of Curcumin and α-Lipoic Acid in Attenuating Weight Gain and Adiposity.

Objective: Obesity is growing at epidemic proportions worldwide. Natural compounds curcumin and α-lipoic acid have been shown to reduce body-weight gain in both preclinical and clinical studies. This study examined the effect of a combination of curcumin and α-lipoic acid on weight gain and adiposity in high-fat-diet (HFD)-fed mice. Methods: C57BL6 mice (7 weeks old) were randomly assigned to receive either HFD (60% fat) or a normal diet (ND, 10% fat) for a 12-week period, following which the mice receiving HFD were further assigned to supplemental curcumin (0.07%), α-lipoic acid (0.2%), or a combination of curcumin and α-lipoic acid formulated into the HFD for a further 12 weeks. Food intake and body mass were determined on a weekly basis. Body fat composition was determined by dual energy X-ray absorptiometry. Results: Treatment with both curcumin and α-lipoic acid significantly reduced body weight gain in HFD-treated mice, and the combination was more effective in attenuating body weight compared to the individual agents. Food intake and caloric intake were significantly lower in the mice that received α-lipoic acid. Percentage body fat and fat mass and lean body mass, which were increased following HFD feeding, were attenuated in the mice receiving curcumin and the combination. Lean mass was also elevated in the mice that were subjected to an HFD, which was unaltered by curcumin or the combination. Conclusions: Taken together, the combination of curcumin and α-lipoic acid exhibits an additive effect in reducing weight gain and adiposity in response to high-fat feeding.