  Citation: George, K.S.; Munoz, J.; Ormsbee, L.T.; Akhavan, N.S.; Foley, E.M.; Siebert, S.C.; Kim, J.-S.; Hickner, R.C.; Arjmandi, B.H. The Short-Term Effect of Prunes in Improving Bone in Men. Nutrients 2022, 14, 276. https://doi.org/10.3390/ nu14020276 Academic Editors: Giuseppe Annunziata, Gian Carlo Tenore and Ettore Novellino Received: 9 December 2021 Accepted: 4 January 2022 Published: 10 January 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). nutrients Article The Short-Term Effect of Prunes in Improving Bone in Men Kelli S. George 1,2 , Joseph Munoz 2 , Lauren T. Ormsbee 2 , Neda S. Akhavan 2,3 , Elizabeth M. Foley 4 , Shalom C. Siebert 2 , Jeong-Su Kim 2,3 , Robert C. Hickner 3,5 and Bahram H. Arjmandi 2,3, * 1 Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26506, USA; kelli.george@mail.wvu.edu 2 Center for Advancing Exercise and Nutrition Research on Aging, Florida State University, Tallahassee, FL 32304, USA; jm12t@my.fsu.edu (J.M.); lormsbee@fsu.edu (L.T.O.); nsa08@my.fsu.edu (N.S.A.); ss17u@my.fsu.edu (S.C.S.); jkim6@fsu.edu (J.-S.K.) 3 Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL 32304, USA; rhickner@fsu.edu 4 Department of Epidemiology and Cancer Control, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; elizabeth.foley@stjude.org 5 Institute for Successful Longevity, Florida State University, Tallahassee, FL 32304, USA * Correspondence: barjmandi@fsu.edu Abstract: Osteoporosis is a major health concern in aging populations, where 54% of the U.S. pop- ulation aged 50 and older have low bone mineral density (BMD). Increases in inflammation and oxidative stress play a major role in the development of osteoporosis. Men are at a greater risk of mortality due to osteoporosis-related fractures. Our earlier findings in rodent male and female models of osteoporosis, as well as postmenopausal women strongly suggest the efficacy of prunes (dried plum) in reducing inflammation and preventing/reversing bone loss. The objective of this study was to examine the effects of two doses of prunes, daily, on biomarkers of inflammation and bone metabolism in men with some degree of bone loss (BMD; t-score between −0.1 and −2.5 SD), for three months. Thirty-five men between the ages of 55 and 80 years were randomized into one of three groups: 100 g prunes, 50 g prunes, or control. Consumption of 100 g prunes led to a significant decrease in serum osteocalcin (p < 0.001). Consumption of 50 g prunes led to significant decreases in serum osteoprotegerin (OPG) (p = 0.003) and serum osteocalcin (p = 0.040), and an increase in the OPG:RANKL ratio (p = 0.041). Regular consumption of either 100 g or 50 g prunes for three months may positively affect bone turnover. Keywords: osteoporosis; bone diseases; metabolic; men; inflammation; antioxidant 1. Introduction Osteoporosis has significant public health importance for both women and men. It is estimated that 53.6 million adults have osteoporosis and low bone mineral density (BMD), representing approximately 54% of the adult population aged 50 years and older in the United States (U.S.) [1–3]. The culprit of many chronic diseases and conditions, including osteoporosis, is chronic inflammation [4]. It is known that inflammation alters bone remodeling, resulting in bone loss [5–8]. With time, this continual loss of bone may lead to impairments in the ability to perform everyday tasks, as well as an increased risk of falls and fractures [8,9]. Decreasing inflammation is an important therapeutic target for the prevention of osteoporosis. Inflammation is perpetuated by increases in oxidative stress [10,11]; therefore, antioxidants and substances rich in antioxidants, such as prunes (Prunus domestica L.), are of great interest for preventing the inflammatory state. Although there has been previous work that provides evidence for the effectiveness of prunes in preventing and reversing bone loss and inflammation in postmenopausal women, there is a lack of such studies in men. Nutrients 2022, 14, 276. https://doi.org/10.3390/nu14020276 https://www.mdpi.com/journal/nutrients