Summary
Background
Preclinical and clinical investigations have revealed the metabolic health benefits of gamma-aminobutyric acid (GABA) supplementation. Exercise training is widely acknowledged for its positive effects on the health of individuals with obesity.
Objective
To investigate the effects of combined GABA supplementation and exercise training on the body composition, nutritional intake, physical performance, and serum biomarkers of women with obesity.
Methods
Twenty-six women with obesity were investigated in this randomized, double-blind, placebo-controlled trial. They received daily GABA (200 mg) supplementation for 90 days alongside exercise training (3 days/week).
Results
For intragroup comparisons hand grip improved in both groups (placebo, p = 0.00276; GABA, p = 0.00012), while sit-up performance increased only in the GABA group (p = 0.00664). Body mass index (p = 0.01273) and waist circumference (p = 0.01393) decreased in the GABA group. In the placebo group, body mass (p = 0.02956), fat-free mass (p = 0.00344), and basal metabolic rate (BMR) (p = 0.00386) decreased, while body fat increased (p = 0.02666). There were no differences in daily macronutrient intake, BMR, body mass, body fat, fat mass, fat-free mass, hip circumference, waist-hip ratio, blood pressure, heart rate, or serum levels of glucose, triglycerides, leptin, resistin, chemokine (C–C motif) ligand 2, chemokine ligand 16, and growth hormone between groups.
Conclusion
GABA supplementation combined with exercise training enhanced physical performance, accompanied by modest improvements in body composition, with no adverse effects on nutritional, physiological, or blood serum parameters.
Introduction
Obesity is a major global public health concern. Current healthcare models that intervene only after the development of obesity-related comorbidities must be replaced with approaches that recognize obesity as a chronic disease. A key priority in obesity treatment should be the promotion of a healthy diet and regular physical activity across various settings [1] (see Fig. 1).
In addition to diet and exercise, additional strategies for managing obesity must be identified. Gamma-aminobutyric acid (GABA), an amino acid that functions as an inhibitory neurotransmitter in the central nervous system, has been recognized as a potential anti-obesity compound. It can regulate obesity through its anti-inflammatory, antioxidant, and glucose metabolism-enhancing properties [[2], [3], [4]]. Studies of diabetic mice have shown that GABA administration improves glucose metabolism by increasing β-cell mass and function, without affecting body weight [5,6].
GABA increases insulin secretion, improves lipid profiles, regulates stress, and influences growth hormone (GH) secretion [[7], [8], [9]]. It is also associated with various physiological processes due to its anti-hypertensive, anti-diabetic, and anti-inflammatory effects [[10], [11], [12]]. Additionally, GABA promotes fat loss and supports muscle mass growth [9,[13], [14], [15], [16]].
GABA can also induce musculoskeletal adaptations such as muscle hypertrophy via GH secretion [9,17,18]. A deficiency in GH secretion has been associated with an increase in body fat, and a decrease in fat-free mass and exercise performance [19]. Furthermore, rats fed a high-fructose diet supplemented with GABA combined with physical exercise reduced body weight gain, as well as fat tissue and liver weight [20].
Several studies have investigated the effects of GABA as a dietary supplement [18,[21], [22], [23]]. In these studies, GABA was not associated with any serious adverse effects; only a small transient effect comprising a 10 % reduction in blood pressure was reported [15]. The present study investigated the anthropometric, biochemical, hormonal, immunological, and physical performance parameter effects of low-dose oral GABA supplementation combined with regular exercise in women with obesity.
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Section snippets
Ethics approval
The experimental protocol was approved by the Research Ethics Committee of the Federal University of Ouro Preto under the registration numbers CAAE: 40000620.3.0000.5150. The study was registered at https://ensaiosclinicos.gov.br/rg/under the code RBR-8t7h259. An informed consent form was diligently presented to the participants, which they signed accordingly.
Study design and participants
A randomized, double-blind, placebo-controlled, parallel-arm clinical trial was conducted. The participants were women with obesity with
Results
In the placebo group, body mass decreased by −1.34 ± 1.86 kg after 12 weeks of training (T0 = 91.56 ± 13.82 vs. T90 = 90.22 ± 14.07; p = 0.02956). However, body fat increased by 0.97 % (T0 = 46.08 ± 4.65 vs. T90 = 47.05 ± 4.38; p = 0.02666) and fat-free mass decreased by −0.91 % after 12 weeks (T0 = 27.19 ± 2.92 vs. 26.28 ± 2.89; p = 0.00344) (Table 1).
In the GABA group, BMI and waist circumference decreased by −0.41 kg m−2 (T0 = 30.63 ± 2.29 vs. T90 = 30.22 ± 2.38; p = 0.01393) and −2.02 cm
Discussion
In this randomized, double-blind, placebo-controlled, parallel-arm clinical trial, women with obesity were assessed over a 12-week period of GABA supplementation (200 mg per day) combined with exercise training. Participants in the GABA group maintained body fat mass and fat-free mass differently from those in the placebo group, who had increased fat mass and decreased fat-free mass after 12 weeks of intervention.
The unexpected results in the placebo group, despite higher adherence to exercise
Conclusion
The combined intervention of GABA supplementation and exercise training resulted in enhanced physical performance (hand grip and sit-ups), accompanied by modest improvements in body composition (BMI and waist circumference). There were no adverse effects on nutritional (daily macronutrient intake), physiological (basal metabolic rate, blood pressure, and heart rate), or blood serum parameters (glucose, triglycerides, leptin, resistin, CCL2, CXCL16, and GH levels).
Author contributions
FGDS, ECO and LKB contributed to the conception, design, funding, and supervision of the study. LVMP, ABM, COT, RSB, TGP, VLTS and KMCP performed the study (physical training, data collection and data tabulation). ECO performed the statistics test. LVMP, ECO and LKB drafted the manuscript. FGDS, DBC, KMCP, ECO and LKB performed critical revisions of the manuscript. All authors contributed to the manuscript final text and approved the submitted version.
Ethical considerations
The experimental protocol was submitted to and approved by the Research Ethics Committee of the Federal University of Ouro Preto, under the number CAAE: 40000620.3.0000.5150. The informed consent form was read and signed by the volunteer.
Funding statement
National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq), Coordination and Improvement of Superior Education Staff (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES), Minas Gerais State Research Support Foundation (Fundação de Amparo à Pesquisa do Estado de Minas Gerais - FAPEMIG, APQ-00662-22), and Pro-Rectory of Research, Postgraduate and Innovation of the Federal University of Ouro Preto (
Declaration of competing interest
Authors declare no conflict of interest.
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