(P20-035-23) Blackcurrants Shape Distinct Gut Microbiota Profile and Reduce Risk of Postmenopausal Osteoporosis Potentially via Gut Microbiome-Immune System-Bone Axis

Objectives: Beneficial effects of blackcurrant (BC) supplementation on bone metabolism have recently been demonstrated, but the role of gut microbiota and its mechanism of action remain unknown. The current study aimed to investigate the effects of BC supplementation on changes in the gut microbiota abundance and composition, immune and endocrine biomarkers and their relationships with changes of bone mass.

Methods: The effects of BC supplementation on bone density, gut microbiota and immune/inflammation and endocrine biomarkers were evaluated using DXA, stool specimens and fasting blood samples collected from a 3-arm, randomized, double-blind, placebo-controlled clinical trial in peri- and early postmenopausal women. Forty peri- and early postmenopausal women aged 45-60 years were randomly assigned into one of three treatment groups for six months: placebo (control group), 392mg/day BC powder (low-BC group) and 784mg/day BC powder (high-BC group).

Results: Both doses of blackcurrant were able to prevent the loss of whole-body BMD compared with that of the control group (P < 0.05). Peripheral IL-1β (P < 0.05) and TRANCE/RANKL (P=0.066 in %change) was reduced by BC treatment compared to the control group. Changes in whole-body BMD over 6-months were inversely correlated with 6-month changes in TRANCE/RANKL (P < 0.01) and IL-4 (P=0.098). The relative abundance of Alistipes, a recovery-related bacteria playing a key role in restoring microbial balance in the gut, dose-dependently increased in 3 groups by time (P < 0.05). Six bacteria known as key symbionts of the gut ecosystem, including Gordonibacter, Ruminococcus, and Holdemania were identified to be correlated with total BMD changes in high BC group (P < 0.05).

Conclusions: Taken all together, the findings of this study suggest that daily consumption of 784 mg of blackcurrant for 6-month might mitigate the risk of postmenopausal bone loss potentially through enhancing gut microbial balance and modulating TRANCE/RANKL, an osteoclastogenic cytokine that links the bone and the immune system.

Funding Sources: This research was funded by the USDA NIFA Seed Grant to Dr. Ock K. Chun. We thank just the berries Ltd. for providing the blackcurrant extract.