Progress 08/01/03 to 01/31/05
Outputs
The purpose of this one year project was to investigate the osteoprotective effects of dried plum in a male animal model of osteoporosis. In the U.S. alone, 2 million men are afflicted with osteoporosis and another 12 million are considered at risk. While most treatment options have targeted postmenopausal osteoporosis, over the past decade therapeutic strategies for osteopenia and/or osteoporosis in males have been evaluated on a limited basis. Among the dietary approaches for improving skeletal health, dried plum has been found to have some of the most potent effects on bone by both preventing and reversing bone loss in female osteoporosis models. However, to date the effectiveness of dried plum in the prevention of bone loss in males has not been examined. To achieve the objectives outlined in this project, we performed an animal study using 6-month old male Sprague Dawley rats (n=60). The orchidectomized rat was utilized in this study to mimic the bone loss induced
by hypogonadism, a major risk factor for osteoporosis in men. Rats were randomly assigned to the sham-operated (Sham=1 group) or orchidectomized (Orx=4 groups) groups and dietary treatments were initiated immediately following surgery. The treatments consisted of one of four doses of dried plum (i.e. 0, 5%, 15%, or 25% w/w) incorporated into a standard semi-purified diet for 90 days. The efficacy of dried plum was determined based on bone density, microarchitectural and biomechanical measures, as well as alterations in bone metabolism. We found that dried plum at the two higher doses completely prevented the Orx-induced decrease in bone mineral density of the whole body, femur, and fourth lumbar vertebra. Biomechanical properties of both the cortical and trabecular bone were also preserved in the orchidectomized rats consuming these two diets. These same doses of dried plum prevented the deterioration in trabecular bone microarchitecture of the distal femur and vertebral body as
indicated by bone volume, trabecular number and separation. At the end of the 90-day treatment period, serum insulin-like growth factor-I was increased and urinary deoxypyridinoline crosslink excretion was decreased suggesting that bone formation was enhanced and bone resorption was suppressed in the groups consuming the dried plum. The mRNA levels for alkaline phosphatase as well as the bone matrix protein, Type I collagen, were up-regulated in a dose-dependent manner with dried plum providing further evidence that osteoblast activity was increased. Based on the results of this study, we conclude that dried plum has potent effects on the male skeleton, which are similar to those previously observed in females. The results of this study suggest that incorporation of dried plum into the diet provides protection against bone loss by inhibiting bone resorption and enhancing bone formation. Nonetheless, these findings related to bone metabolism are preliminary and should be confirmed by
histomorphometric assessment of bone metabolism at the tissue level. Further work is also warranted to identify the bioactive components in dried plum responsible for these compelling osteoprotective effects.
Impacts
An important public health strategy for reducing the incidence of osteoporosis is to identify foods and their bioactive compounds that could prevent and/or reverse bone loss. Dried plums, rich in antioxidants, have previously been shown to have positive effects on the skeletal health of female animal models. The results of this study demonstrate that males also benefit from these same osteoprotective effects are also afforded to male animal models of osteoporosis. These findings provide fundamental evidence for clinical studies to evaluate whether the incorporation of dried plums into the diet can protect men and women against bone loss and reduce the risk of osteoporotic fracture.
Publications
- Franklin M, Lucas EA, Lancaster EA, Soung DY, Devareddy L, Bellmer DD, Marlow DD, Arjmandi BH, Smith BJ. Dried plum prevents bone loss in animal model of male osteoporosis. J Bone Min Res 2004;19:M447.
- Smith BJ, Franklin M, Lancaster EA, Lucas EA, Bu SY, Devareddy L, Arjmandi BH. Dried plum restores bone mass and microarchitecture in osteopenic orchidectomized rats. FASEB J 2005;19(4):A56.
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