Effects of dried tofu supplementation during interval walking training on the methylation of the NFKB2 gene in the whole blood of older women.

Muscle atrophy with aging is closely associated with chronic systemic inflammation and lifestyle-related diseases. Here, we assessed whether dried tofu intake during 5-month interval walking training (IWT) enhanced increases in thigh muscle mass and strength and ameliorated susceptibility to inflammation in older women. Subjects (n = 32, ~ 65 years) who performed IWT for > 6 months participated in this study. They were randomly divided into 2 groups: IWT + placebo intake (PLG, n = 16; 108 kcal, 0.2 g protein, 5.5 g fat, and 14.4 g carbohydrate) and IWT + dried tofu intake (DTG, n = 16; 111 kcal, 9.6 g protein, 6.0 g fat, and 4.6 g carbohydrate). They were instructed to repeat ≥ 5 sets of fast and slow walking for 3 min each at ≥ 70 and 40% peak aerobic capacity for walking, respectively, per day for ≥ 4 days/week. Immediately after daily exercise, subjects were instructed to consume the supplements assigned to each group. In the DTG, after IWT, the methylation increased at 4/6 sites in the promoter region of the NFKB2 gene in the whole blood (all, P < 0.04), with an 18% increase in the average methylation of the 6 sites (P = 0.035). On the other hand, in the PLG, the increase occurred at only 2/6 sites, with no significant increase in the average methylation of the 6 sites. No significant differences were observed in increases in thigh muscle strength or cross-sectional area between the groups (all, P > 0.2). Altogether, dried tofu supplementation during IWT likely enhanced the methylation of the NFKB2 gene more than IWT alone, without detectably enhanced increases in thigh muscle strength or cross-sectional area.