Table 1.

Baseline characteristics of the selected volunteers.

Group	Number	Age range/year	Gender	Gastrointestinal disease	Taking antibiotics and other medicines
Young men	11	20–30	Male	None	None
Older men	10	40–60	Male	None	None
Young women	10	20–30	Female	None	None
Older women	10	40–60	Female	None	None