Table 1. Baseline values for the general characteristics and sleep status variables according to the three intervention groups.
| Variables | Intervention groups* | |||||
|---|---|---|---|---|---|---|
| Group A | Group B | Group C | ||||
| Placebo | γ-PGA | Placebo | VitB6 | Placebo | γ-PGA + VitB6 | |
| Number of participants | 16 | 14 | 17 | |||
| Age (yrs) | 24.93 ± 2.43 | 24.42 ± 1.98 | 25.17 ± 2.69 | |||
| Male and female | 8 (50.0%)/8 (50.0%) | 8 (57.1%)/6 (42.9%) | 9 (52.9%)/8 (47.1%) | |||
| Body mass index (kg/m2) | 23.0 ± 2.97 | 22.9 ± 3.06 | 23.4 ± 3.66 | 23.4 ± 3.67 | 24.1 ± 4.38 | 24.1 ± 4.41 |
| Caffeine intake (mg/day) | 283.3 ± 282.7 | 237.6 ± 384.1 | 158.1 ± 148.9 | 148.2 ± 150.7 | 234.5 ± 174.9 | 281.2 ± 187.8 |
| Sleep duration (hours/day) | 6.72 ± 1.45 | 7.05 ± 1.02 | 6.97 ± 1.89 | 6.98 ± 1.22 | 6.76 ± 1.19 | 6.82 ± 1.07 |
| PSQI | 4.81 ± 2.56 | 4.56 ± 1.96 | 6.07 ± 2.81 | 5.85 ± 2.47 | 4.76 ± 2.81 | 4.82 ± 2.55 |
| ESS | 5.75 ± 3.90 | 6.06 ± 3.21 | 5.57 ± 3.36 | 6.35 ± 3.00 | 6.41 ± 3.42 | 6.58 ± 3.95 |
| Serum serotonin (ng/mL) | 185.4 ± 48.1 | 183.5 ± 46.0 | 177.9 ± 57.1 | 170.8 ± 70.0 | 171.4 ± 50.8 | 168.6 ± 48.7 |
Variable values are presented as mean ± SD.
γ-PGA, poly-γ-glutamic acid; VitB6, vitamin B6; PSQI, Pittsburgh Sleep Quality Index; ESS, Epworth Sleepiness Scale.
*Group A received γ-PGA supplementation only; Group B received VitB6 supplementation only; Group C received both γ-PGA and VitB6 supplementation.