Rationale and study design of Randomized Controlled Trial of Dietary Supplementation with prune (dried plums) on bone density, geometry, and estimated bone strength in postmenopausal women: The Prune study

The use of non-pharmacological alternatives to pharmacological interventions, e.g., nutritional therapy, to improve or maintain bone mineral density (BMD) in postmenopausal women has gained traction over the past decade, but limited data exist regarding its efficacy. This paper describes the design of the Prune Study, a randomized controlled trial (RCT) that explored the effectiveness of a 12-month intervention of daily prune consumption on bone density, bone structure and strength estimates, bone turnover, various biomarkers of immune function, inflammation, and cardiovascular health, as well as phenolic and gut microbiota analyses. Postmenopausal women between the ages of 55–75 years were randomized into either control group (no prune consumption; n = 78), 50g prune (50g prune/day; n = 79), or 100g prune (100g prune/day; n = 78). All participants received 1200 mg calcium +800 IU vitamin D(3) daily as standard of care. The Prune Study is the largest and most comprehensive investigation of a dose response of prune consumption on bone health, biomarkers of immune function, inflammation, and cardiovascular health, as well as detailed phenolic and gut microbiota analyses in postmenopausal women. 235 women were randomized and 183 women completed the entire study. The findings of this study will help expand our current understanding of clinical implications and mechanisms underlying the resultant health effects of prune as a functional food therapy.