J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 11, Number 6, June 2019, pages 428-434

Oral Supplementation Using Gamma-Aminobutyric Acid and Whey Protein Improves Whole Body Fat-Free Mass in Men After Resistance Training

Figure 1. Resting plasma growth hormone concentrations. Values represent the mean ± standard error for 10 subjects (the whey protein group (WP)) or 11 subjects (the whey protein + gamma-aminobutyric acid group (WP + GABA)). *P < 0.05 vs. baseline of the WP + GABA group; **P < 0.05 vs. baseline of the WP group.

Figure 2. Change in body composition after 12 weeks as measured using dual-energy X-ray absorptiometry. (a) Whole body fat-free mass and (b) arm and leg lean mass. Values represent the mean ± standard error for 10 subjects (the whey protein group (WP)) or 11 subjects (the whey protein + gamma-aminobutyric acid group (WP + GABA)). *P < 0.05 vs. the WP group.

**Table 1.** Nutritional Intake Values at Baseline and After 12 Weeks
	WP group	WP + GABA group	ANOVA
Data are reported as mean ± standard deviation. WP: whey protein; WP + GABA: whey protein + gamma-aminobutyric acid; ANOVA: analysis of variance; G: group effect; T: time effect; G × T: group × time effect.
Energy intake (kcal/day)	2,153 ± 1,034	2,105 ± 723	1,681 ± 585	1,761 ± 395	G: P = 0.186, T: P = 0.907, G × T: P = 0.651
Protein intake (g/day)	69 ± 24	75 ± 24	61 ± 26	62 ± 20	G: P = 0.302, T: P = 0.431, G × T: P = 0.488
Carbohydrate intake (g/day)	303 ± 170	299 ± 125	219 ± 79	218 ± 58	G: P = 0.103, T: P = 0.913, G × T: P = 0.925
Fat intake (g/day)	53 ± 19	54 ± 18	49 ± 21	50 ± 15	G: P = 0.608, T: P = 0.809, G × T: P = 0.957

Table 1. Nutritional Intake Values at Baseline and After 12 Weeks

WP group

WP + GABA group

ANOVA

Baseline

12 weeks

Baseline

12 weeks

Data are reported as mean ± standard deviation. WP: whey protein; WP + GABA: whey protein + gamma-aminobutyric acid; ANOVA: analysis of variance; G: group effect; T: time effect; G × T: group × time effect.

Energy intake (kcal/day)

2,153 ± 1,034

2,105 ± 723

1,681 ± 585

1,761 ± 395

G: P = 0.186, T: P = 0.907, G × T: P = 0.651

Protein intake (g/day)

69 ± 24

75 ± 24

61 ± 26

62 ± 20

G: P = 0.302, T: P = 0.431, G × T: P = 0.488

Carbohydrate intake (g/day)

303 ± 170

299 ± 125

219 ± 79

218 ± 58

G: P = 0.103, T: P = 0.913, G × T: P = 0.925

Fat intake (g/day)

53 ± 19

54 ± 18

49 ± 21

50 ± 15

G: P = 0.608, T: P = 0.809, G × T: P = 0.957

**Table 2.** Maximal Strength Values at Baseline and After 12 Weeks
	WP group	WP + GABA group	ANOVA
Data are reported as mean ± standard deviation. WP: whey protein; WP + GABA: whey protein + gamma-aminobutyric acid; ANOVA: analysis of variance; G: group effect; T: time effect; G × T: group × time effect.
Leg press (kg)	127 ± 31	202 ± 53	133 ± 38	230 ± 74	G: P = 0.414, T: P = 0.000, G × T: P = 0.404
Leg extension (kg)	64 ± 17	91 ± 33	64 ± 13	91 ± 15	G: P = 0.968, T: P = 0.000, G × T: P = 0.947
Leg curl (kg)	53 ± 14	77 ± 22	55 ± 11	78 ± 19	G: P = 0.866, T: P = 0.000, G × T: P = 0.929
Chest press (kg)	52 ± 11	65 ± 13	63 ± 14	78 ± 16	G: P = 0.058, T: P = 0.000, G × T: P = 0.727
Pull down (kg)	59 ± 15	73 ± 15	65 ± 15	78 ± 15	G: P = 0.411, T: P = 0.000, G × T: P = 0.876

Table 2. Maximal Strength Values at Baseline and After 12 Weeks

WP group

WP + GABA group

ANOVA

Baseline

12 weeks

Baseline

12 weeks

Leg press (kg)

127 ± 31

202 ± 53

133 ± 38

230 ± 74

G: P = 0.414, T: P = 0.000, G × T: P = 0.404

Leg extension (kg)

64 ± 17

91 ± 33

64 ± 13

91 ± 15

G: P = 0.968, T: P = 0.000, G × T: P = 0.947

Leg curl (kg)

53 ± 14

77 ± 22

55 ± 11

78 ± 19

G: P = 0.866, T: P = 0.000, G × T: P = 0.929

Chest press (kg)

52 ± 11

65 ± 13

63 ± 14

78 ± 16

G: P = 0.058, T: P = 0.000, G × T: P = 0.727

Pull down (kg)

59 ± 15

73 ± 15

65 ± 15

78 ± 15

G: P = 0.411, T: P = 0.000, G × T: P = 0.876

**Table 3.** Body Composition at Baseline and After 12 Weeks
	WP group	WP + GABA group	ANOVA
Data are reported as mean ± standard deviation. WP: whey protein; WP + GABA: whey protein + gamma-aminobutyric acid; BMI: body mass index; ANOVA: analysis of variance; G: group effect; T: time effect; G × T: group × time effect.
Weight (kg)	70.5 ± 8.6	70.8 ± 9.0	70.5 ± 8.9	71.7 ± 10.4	G: P = 0.917, T: P = 0.079, G × T: P = 0.252
Fat mass (kg)	16.8 ± 4.9	16.9 ± 5.4	16.4 ± 5.6	16.3 ± 6.3	G: P = 0.846, T: P = 0.957, G × T: P = 0.773
BMI (kg/m²)	23.3 ± 2.2	23.4 ± 2.3	24.2 ± 3.6	24.6 ± 4.1	G: P = 0.501, T: P = 0.089, G × T: P = 0.247
Whole body fat-free mass (kg)	50.9 ± 4.7	51.0 ± 4.6	51.2 ± 5.4	52.5 ± 6.2	G: P = 0.714, T: P = 0.011, G × T: P = 0.037
Arm and leg lean mass (kg)	23.0 ± 2.3	23.6 ± 2.7	23.4 ± 2.8	24.2 ± 2.9	G: P = 0.695, T: P = 0.001, G × T: P = 0.584

Table 3. Body Composition at Baseline and After 12 Weeks

WP group

WP + GABA group

ANOVA

Baseline

12 weeks

Baseline

12 weeks

Data are reported as mean ± standard deviation. WP: whey protein; WP + GABA: whey protein + gamma-aminobutyric acid; BMI: body mass index; ANOVA: analysis of variance; G: group effect; T: time effect; G × T: group × time effect.

Weight (kg)

70.5 ± 8.6

70.8 ± 9.0

70.5 ± 8.9

71.7 ± 10.4

G: P = 0.917, T: P = 0.079, G × T: P = 0.252

Fat mass (kg)

16.8 ± 4.9

16.9 ± 5.4

16.4 ± 5.6

16.3 ± 6.3

G: P = 0.846, T: P = 0.957, G × T: P = 0.773

BMI (kg/m²)

23.3 ± 2.2

23.4 ± 2.3

24.2 ± 3.6

24.6 ± 4.1

G: P = 0.501, T: P = 0.089, G × T: P = 0.247

Whole body fat-free mass (kg)

50.9 ± 4.7

51.0 ± 4.6

51.2 ± 5.4

52.5 ± 6.2

G: P = 0.714, T: P = 0.011, G × T: P = 0.037

Arm and leg lean mass (kg)

23.0 ± 2.3

23.6 ± 2.7

23.4 ± 2.8

24.2 ± 2.9

G: P = 0.695, T: P = 0.001, G × T: P = 0.584