The Effect of 12-Month Prune (Dried Plum) Supplementation on Pro-inflammatory Cytokine Secretion in Postmenopausal Women

Abstract

Objectives Osteoporosis is characterized by decreased bone strength and increased risk for fracture and is estimated to affect over 200 million women worldwide, causing approximately 9 million fractures annually. Current pharmacological therapies include antiresorptive and anabolic agents to treat low bone mineral density (BMD) but are associated with high cost, poor compliance, and adverse effects, contributing to their declining use and popularity. There is increasing interest in the potential of whole food dietary interventions to mitigate postmenopausal bone loss. Prunes (dried plums) are an abundant source of bioactive phenolic compounds that can target inflammatory pathways, which are upregulated in a hypoestrogenic environment and consequently promote bone loss. However, few studies have evaluated the effect of prunes on inflammatory mediators in postmenopausal women. This study aimed to evaluate the effect of 12 months of prune consumption (two doses, 50 and 100 g) on pro-inflammatory cytokine secretion in postmenopausal women. Methods Postmenopausal women (n = 87, 55–75 years old) were recruited for a single-center, parallel-arm, 12-month randomized controlled trial to test the effects of 50 g and 100 g prunes/day compared to a control group on inflammatory mediators. All participants received 1200 m g calcium and 800 IU vitamin D3 as standard of care. Blood was collected at baseline and after 12 months of prune consumption. Peripheral blood mononuclear cells (PBMCs) were isolated at each time point and stimulated with lipopolysaccharide (LPS). Pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8, MCP-1) were quantified by ELISA in the supernatants from LPS-stimulated PBMCs and in plasma. Results Prune consumption did not alter plasma pro-inflammatory cytokine concentrations. However, in supernatants from LPS-stimulated PBMCs, there were reductions in IL-1β (P = 0.013), IL-6 (P = 0.007), and IL-8 (P = 0.049) secretion in the 100 g prunes/day group and in TNF-α (P < 0.001) secretion in the 50 g prunes/day group compared to the control group. Conclusions Consumption of 50g-100g/day of prunes for 12 months attenuated TNF-α, IL-1β, IL-6, and IL-8 production from LPS-stimulated PBMCs in postmenopausal women, suggesting a potential anti-inflammatory effect secondary to prune consumption. Funding Sources California Prune Board.