Abstract
BACKGROUND: Oral probiotic intake is suggested to have positive effects on skin. We aimed to elucidate the effects of oral Bifidobacterium breve M-16V intake on skin by analyzing facial images, the skin myco/microbiota, and the gut microbiota. METHODS: We conducted a randomized, double-blind, placebo-controlled study in Japan. Healthy women aged over 30 years were randomly allocated to either the B. breve (1 × 1010 colony-forming units (CFU)/sachet, two sachets daily) or the placebo group and consumed the corresponding study food for 12 weeks. Facial images were taken at weeks 0, 4, 8, and 12 using VISIA evolution. Stool and skin samples were collected at weeks 0 and 12. The primary outcome was the change in the total VISIA score from baseline. RESULTS: A total of 120 females aged 30-79 years were assigned to the B. breve (n = 59) or placebo (n = 61) group. The total VISIA score worsened in the placebo group at week 8 (p = 0.029) but not in the B. breve group. Compared with that of the placebo group, the VISIA brown spot score of the B. breve group improved at weeks 4 (p = 0.013) and 8 (p = 0.041). The VISIA pore score improved at weeks 4 (p = 0.013), 8 (p = 0.041), and 12 (p = 0.004) within the B. breve group. Genus-level analysis of the gut microbiota revealed a significant increase in Blautia abundance in the B. breve group. The frequency of adverse events was not different between the groups. CONCLUSIONS: Oral B. breve M-16V administration may suppress skin deterioration, including the appearance of brown spots, on the faces of adult females.