Effect of Kurozu on Peripheral Blood Cells and NK Cell Activity in Student Bicycle Racers

We investigated the effect of kurozu, a brewed vinegar, on the NK cell activity and peripheral blood cells in 18 university student cyclists. They were assigned to two groups, one of 11 drinking kurozu, and the other of 7 cyclists not drinking it. The drinking group was given 30 ml of kurozu a day for 80 days. Both groups performed an equal amount of training for 80 days. The NK cell activity was significantly decreased by 80 days of training in the non-drinking group (from 71.9 ± 15.9% to 61.9 ± 11.3%) (p < 0.05), but not in the drinking group. Kurozu therefore prevent the degradation of NK cell activity by intense training, suggesting its contribution to the physical condition of student bicycle racers.