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Oral Supplementation Using Gamma-Aminobutyric Acid and Whey Protein Improves Whole Body Fat-Free Mass in Men After Resistance Training
Maya Sakashita, Utano Nakamura, Noriko Horie, Yasuhiro Yokoyama, Mujo Kim, Satoshi Fujita
Abstract
Background: Oral gamma-aminobutyric acid (GABA) supplementation increases growth hormone (GH) serum levels and protein synthesis. Therefore, post-exercise supplementation using GABA and protein may help enhance training-induced muscle hypertrophy. We evaluated whether GABA with whey protein enhanced muscular hypertrophy in men after progressive resistance training.
Methods: Twenty-one healthy men (26 - 48 years) were randomized to receive whey protein (WP; 10 g) or whey protein + GABA (WP + GABA; 10 g + 100 mg) daily for 12 weeks. Both groups performed resistance training twice per week (three sets of 12 repetitions at 60% of maximal strength; leg press, leg extension, leg curl, chest press, and pull down). Body composition was assessed using dual-energy X-ray absorptiometry.
Results: In the WP + GABA group, resting plasma GH concentrations were significantly elevated at 4 and 8 weeks, compared to baseline. However, resting plasma GH concentrations in the WP group were only significantly elevated at 8 weeks. After 12 weeks, the WP + GABA group exhibited significantly greater increase in whole body fat-free mass than the WP group.
Conclusions: The GABA and whey protein combination was more effective for increasing whole body fat-free mass; daily GABA supplementation may help enhance exercise-induced muscle hypertrophy.
Conclusions
To the best of our knowledge, this is the first study to evaluate the effects of GABA in combination with whey protein supplementation on muscular hypertrophy in men during a 12- week program of progressive resistance training. Our results indicate that GABA plus a suboptimal dose of whey protein resulted in significantly enhanced whole body fat-free mass, compared to whey protein alone. Thus, daily supplementation with GABA may be a useful addition to whey protein for enhancing exercise-induced muscle hypertrophy. Nevertheless, further studies are needed to validate our findings, to determine whether GABA directly promotes muscle protein synthesis, and to investigate the mechanism through which GABA enhances lean mass.
Maya Sakashita, Utano Nakamura, Noriko Horie, Yasuhiro Yokoyama, Mujo Kim, Satoshi Fujita
Abstract
Background: Oral gamma-aminobutyric acid (GABA) supplementation increases growth hormone (GH) serum levels and protein synthesis. Therefore, post-exercise supplementation using GABA and protein may help enhance training-induced muscle hypertrophy. We evaluated whether GABA with whey protein enhanced muscular hypertrophy in men after progressive resistance training.
Methods: Twenty-one healthy men (26 - 48 years) were randomized to receive whey protein (WP; 10 g) or whey protein + GABA (WP + GABA; 10 g + 100 mg) daily for 12 weeks. Both groups performed resistance training twice per week (three sets of 12 repetitions at 60% of maximal strength; leg press, leg extension, leg curl, chest press, and pull down). Body composition was assessed using dual-energy X-ray absorptiometry.
Results: In the WP + GABA group, resting plasma GH concentrations were significantly elevated at 4 and 8 weeks, compared to baseline. However, resting plasma GH concentrations in the WP group were only significantly elevated at 8 weeks. After 12 weeks, the WP + GABA group exhibited significantly greater increase in whole body fat-free mass than the WP group.
Conclusions: The GABA and whey protein combination was more effective for increasing whole body fat-free mass; daily GABA supplementation may help enhance exercise-induced muscle hypertrophy.
Conclusions
To the best of our knowledge, this is the first study to evaluate the effects of GABA in combination with whey protein supplementation on muscular hypertrophy in men during a 12- week program of progressive resistance training. Our results indicate that GABA plus a suboptimal dose of whey protein resulted in significantly enhanced whole body fat-free mass, compared to whey protein alone. Thus, daily supplementation with GABA may be a useful addition to whey protein for enhancing exercise-induced muscle hypertrophy. Nevertheless, further studies are needed to validate our findings, to determine whether GABA directly promotes muscle protein synthesis, and to investigate the mechanism through which GABA enhances lean mass.
