Prune Consumption and Bone Health in Older Men: A One-Year Randomized Controlled Trial

Background/Objectives: Approximately 53.4 million U.S. adults aged 50 or older have low bone mass, yet male bone health remains under-researched. This study evaluated the effects of one year of prune supplementation on bone health in older men susceptible to, or with, osteopenia. Methods: A total of 59 men (aged 55–80 years) were randomly assigned to one of three groups: 100 g prunes, 50 g prunes, or 0 g prunes (control; multivitamin only) daily, with each group also receiving 450 mg elemental calcium and 800 IU vitamin D3 via a multivitamin. Dual-energy X-ray absorptiometry (Lunar model DXA; GE Healthcare, CA, USA) scans and blood samples were collected at baseline, 3 months, 6 months, and 12 months. Results: No significant changes were observed in total bone mineral density (BMD) or lumbar spine BMD over one year. There were no significant changes in C-reactive protein (CRP). Osteoprotegerin (OPG) decreased significantly in all groups; however, the decrease was significantly greater in the control group compared to the levels in both prune groups. Sclerostin (SOST) significantly increased over time within all groups. Tartrate-resistant acid phosphatase-5b (TRAP5b) increased in all groups, albeit in the control group, it increased significantly more over time compared to the increase in the 100 g group. Conclusions: Overall, prune supplementation, regardless of dosing, did not increase total or lumbar BMD or aid in maintaining bone density beyond the levels achieved by Ca++ and vitamin D3 supplementation in older men susceptible to, or with, osteopenia (with a negative T-score down to –2.5 standard deviations (SD) below the mean). Although between-group differences were observed in select secondary biomarkers (OPG, TRAP5b), these did not correspond to detectable changes in BMD and should therefore be considered exploratory rather than directly indicative of clinical bone benefit. Additional research is needed to fully understand the effects of prunes on bone metabolism in men.