(P44-34-26) Calcium Absorption Is Increased in Adult Gonadectomized Rats Following Acute and Chronic Prune Supplementation

Objectives: Calcium (Ca) metabolism and bone health is profoundly influenced by sex hormones. Prunes have been identified as a functional food that mitigates hormone-deprivation-induced skeletal issues. This study investigated the effects of acute and chronic dietary prune supplementation on calcium utilization using kinetic modeling in adult ovariectomized (OVX) female and orchiectomized (ORX) male Sprague Dawley rats.

Methods: In an acute 4-day dietary intervention study, 3-months-old female OVX rats (N=43) were randomized to modified AIN-93M diets containing 0%, 5%, 15%, or 25% prune to assess dose-dependent effects on Ca utilization. A second, three-weeks long study using both female OVX (N=26) and male ORX rats (N=26) investigated if Ca utilization effects were sustained with a 15% prune diet. In both studies, Ca isotopic tracers were administered four days prior to sacrifice to quantify whole-body Ca kinetics. Mathematical modeling of tracer kinetic data using WINSAAM was performed to evaluate Ca metabolism including fractional Ca absorption (FCA).

Results: In a positive dose response, acute prune intervention increased FCA from the upper intestine (p < 0.0001): 0.28 (control), 0.42 (5%), 0.49 (15%), and 0.67 (25%). Increased FCA in OVX and ORX rats was sustained in the chronic study using 15% prune diet compared to controls (p < 0.01), though the effect was diminished compared to acute feeding and was more dramatic in males (p < 0.05).

Conclusions: Prune supplementation enhances calcium absorption in sex-hormone-deficient rats, especially with acute intake. These findings support the role of prunes as a potential nutritional strategy to counteract hormone loss–related bone mineral deficits.

Funding Sources: This research was funded by the California Prune Board.