Scientists from Pharma Foods International Co., Ltd, Ritsumeikan University, and Mitsubishi Corporation report that GABA plus whey protein led to increased growth hormone levels after eight weeks of supplementation, compared to whey protein alone. After 12 weeks there were no differences between the groups.
Significant differences between whey protein and whey protein plus GABA groups were also observed for fat-free mass after 12 weeks, according to findings published in the Journal of Clinical Medicine Research.
“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,” wrote the researchers.
“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.”
GABA is a naturally-occurring amino acid and key inhibitory neurotransmitter found in human cells. GABA can be found in a range of foods, with certain fermented foods particularly popular in East Asia like kimchi having especially high concentrations.
The study used the PharmaGABA-branded ingredient from Pharma Foods International, which produces its GABA from the fermentation of lactobacillus using a proprietary process. The ingredient PharmaGABA is self-affirmed GRAS, and reportedly commands over 70% of the Japanese market.
The Japan-based scientists recruited 26 resistance-trained men aged between 26 and 48, and assigned them to receive 10 grams of whey protein per day with or without an additional 100 mg of PharmaGABA. All men trained twice a week for 12 weeks. Twenty-one men completed the study.
Results showed that resting plasma growth hormone levels were significantly increased in the whey plus GABA group after four and eight weeks, but not 12 weeks, compared to baseline values. On the other hand, the whey protein group only had elevated levels at week eight.
Muscle mass, measured using dual-energy X-ray absorptiometry (DXA) at baseline and 12 weeks, showed that muscle mass was significantly increased in the GABA plus whey group.
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.
“[F]urther 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,” concluded the researchers.
Source: Journal of Clinical Medicine Research
2019, Volume 11, Number 6, Pages 428-434, doi: 10.14740/jocmr3817
“Oral Supplementation Using Gamma-Aminobutyric Acid and Whey Protein Improves Whole Body Fat-Free Mass in Men After Resistance Training”
Authors: M. Sakashita et al.