1. Exercise Sciences Research Group, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan.
2. Food Research Department, Yakult Central Institute, 11 Izumi 5-chome, Kunitachi-shi, Tokyo 186-8650, Japan.
3. Microbiological Research Department, Yakult Central Institute, 11 Izumi 5-chome, Kunitachi-shi, Tokyo 186-8650, Japan.
4. Faculty of Kinesiology and Physical Education, University of Toronto, 55 Harbord Street, Toronto, ON M5S 2W6, Canada.