THIS PROJECT IS RELEVANT AND INNOVATIVE TO THE HEALTH OF PERI AND POSTMENOPAUSAL FEMALES FOR MANY REASONS. MODERN MEDICINE DOES NOTHING TO PREVENT OR SLOW DOWN THIS HIGHLY VULNERABLE PERIOD OF BONE LOSS WHICH, IS THE TIME PERIOD WHEN BONE LOSS IS THE GREATEST. IF OUR PROJECT CAN SLOW DOWN AND OR PREVENT BONE LOSS IT CAN POTENTIALLY PREVENT/DELAY OSTEOPOROSIS IN FEMALES- WHICH IS A HUGE BENEFIT. THE LATE PERIMENOPAUSAL AND EARLY POSTMENOPAUSE PERIOD REPRESENTS AN OPPORTUNISTIC WINDOW FOR STUDY BECAUSE BONE LOSS IS AT ITS GREATEST AT THIS TIME WITH FEMALES LOSING AS MUCH AS 6-7% OF BONE. WE ARE PROPOSING TO UTILIZE A WHOLE FOOD, PRUNES, TO SLOW DOWN AND PREVENT BONE LOSS BECAUSE WE HAVE HAD SUCCESS IN SLOWING DOWN AND PREVENTING BONE LOSS IN OLDER POSTMENOPAUSAL FEMALES. IF THIS PROJECT IS SUCCESSFUL AT ATTENUATING BONE LOSS, IT CAN IMMEDIATELY BE DISSEMINATED TO THE PUBLIC TO PROMOTE PRUNE CONSUMPTION TO SLOW DOWN AND ATTENUATE PERIMENOPAUSAL BONE LOSS. AS SUCH, THIS PROJECT COULD IMPROVE THE LONG-TERM BONE HEALTH OF FEMALES AND AVOID OR DELAY OSTEOPOROSIS AND IMPROVE QUALITY OF LIFE. OUR LONG-TERM GOAL IS TO TEST THE NOVEL HYPOTHESIS THAT PRUNE CONSUMPTION FOR 18 MONTHS DURING THE 3-YEAR LATE PERIMENOPAUSALAND EARLY POSTMENOPAUSEPERIOD PREVENTS THE DRAMATIC RATE OF BONE LOSS IN PERIMENOPAUSAL FEMALES DURING A WINDOW OF HEIGHTENED PHYSIOLOGICAL VULNERABILITY. AT PENN STATE UNIVERSITY (DE SOUZA, PI), WE WILL COMPARE THE EFFECTS OF 18 MONTHS OF DAILY DIETARY CONSUMPTION OF 50 G OF PRUNES (5-6) VERSUS A NO-PRUNE CONTROL GROUP ON BONE OUTCOMES (DEXA-DERIVED BMD, PQCT-DERIVED BONE GEOMETRY), MECHANISTIC FACTORS (BONE AND INFLAMMATORY MARKERS, INFLAMMATORY RESPONSE OF EX VIVO CULTURED PBMCS, MONOCYTES), AND GUT MICROBIOME. THIS PROPOSAL IS SUBMITTED IN RESPONSE TO A SPECIFIC COMMODITY BOARD TOPIC: CONDUCT CLINICAL TRIALS DURING LATE PERIMENOPAUSALAND EARLY POSTMENOPAUSEIN FEMALES TO STUDY THE LONG-TERM EFFECTS OF PRUNE CONSUMPTION ON BONE HEALTH.