We previously reported the efficacy of dried plum (Prunus domestica L.) in preventing ovariectomy-induced bone loss in a rat model of osteoporosis and improving bone biomarkers in postmenopausal women. The present study evaluated whether dried plum was able to restore bone mass in osteopenic ovariectomized rats.
Ninety-day-old Sprague-Dawley rats were either sham-operated (Sham; one group) or ovariectomized (Ovx; five groups) and were fed a standard diet for 40 days to establish bone loss and subsequently experimental treatments were initiated. Sham, Ovx control, and Ovx + 17β-estradiol (E2; 10 μg/kg body weight per day) animals continued to receive the standard diet, whereas the remaining three Ovx groups received the following dietary treatments: Ovx + 5% dried plum (low dose), Ovx + 15% dried plum (medium dose), and Ovx + 25% dried plum (high dose). After 60 days, blood and bone specimens were collected for analyses.
Dried plum, as low as 5%, was effective in restoring femoral and tibial bone density. Dried plum increased lumbar bone density as well, with HD achieving a statistical significance. The increase in femoral bone density of dried plum-fed rats resulted in improved bone quality as indicated by 6.9% and 6.0% improvement in overall yield and ultimate force, respectively. Varying doses of dried plum were also able to significantly improve trabecular microarchitectural properties in comparison with ovariectomized controls.
The improvement in biomechanical properties of long bones due to dried plum, in part, may be due to the favorable microstructural changes as evident by enhanced tibial bone volume and connectivity. Loss of bone volume accompanied by loss of trabecular connectivity is generally believed to be an irreversible process, but our observations suggest that dried plum improves trabecular microstructure of tibia after losses have already occurred.
This study demonstrated that dried plum (prunes), as low as 5% of diet, restored femoral and tibial bone density in a rat model of osteopenia. Furthermore, dried plum improved trabecular micro architecture in a dose-dependent manner, a rather unique observation.
From the Departments of 1Nutritional Sciences and 2Biosystems & Agricultural Engineering, Oklahoma State University, Stillwater, OK.
Received November 16, 2004; revised and accepted April 13, 2005.
This study was supported by the California Dried Plum Board.
Address correspondence to: Bahram H. Arjmandi, PhD, RD, Department of Nutritional Sciences, 301 Human Environmental Sciences, Oklahoma State University, Stillwater, OK 74078-6141. E-mail: email@example.com.