Table 3. Differences in the baseline and follow-up values according to the three intervention groups.
| Variables | Intervention groups* | |||||
|---|---|---|---|---|---|---|
| Group A | Group B | Group C | ||||
| Placebo | γ-PGA | Placebo | VitB6 | Placebo | γ-PGA + VitB6 | |
| Caffeine intake (mg/day) | 32.6 ± 170.5 | −14.0 ± 317.8 | −14.9 ± 128.8 | −66.2 ± 119.8 | −1.84 ± 98.5 | −8.16 ± 63.1 |
| Sleep duration (hours/day) | 0.03 ± 1.04 | −0.03 ± 0.71 | 0.14 ± 0.86 | 0.67 ± 0.80 | −0.25 ± 1.25 | 0.27 ± 0.98† |
| PSQI | −0.06 ± 1.73 | 0.31 ± 1.53 | −0.92 ± 1.30 | −0.50 ± 1.95 | 0.64 ± 1.93 | −0.52 ± 1.58† |
| ESS | −0.18 ± 2.83 | −0.68 ± 2.33 | −0.14 ± 2.38 | −1.21 ± 3.04 | 0.11 ± 1.72 | −0.11 ± 1.49 |
| Serum serotonin (ng/mL) | −2.50 ± 50.8 | 1.93 ± 47.7 | 11.5 ± 54.0 | −4.25 ± 49.5 | 17.9 ± 60.5 | 4.59 ± 38.5 |
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. †P<0.05 when being compared with a placebo group in each intervention. Comparison was performed using a nonparametric test.