Master of Science (MS)
The accelerated rate of bone loss that occurs after menopause may be reduced by consuming rice bran oil (RBO), which contains natural oryzanol. Three different forms of oryzanol (natural oryzanol, NO; crystalline oryzanol, CO; and solubilized oryzanol, SO) were evaluated in a rat model of postmenopausal women. Retired Sprague-Dawley breeder rats were stratified by weight and assigned randomly to one of five groups for a thirteen week study. Rats were either variectomized (O, n=37) or sham-operated (ShC, n=10) and assigned to control (C) diets (OC, n=10 or ShC, n=10) or one of three forms of oryzanol (NO, n=9; CO, n=9; or SO, n=9). Bone mineral density of the vertebrae, humerus, femur, and tibia were measured by pDEXA. Results demonstrated that the diet consisting of natural oryzanol (RBO) was slightly protective in preventing bone loss at several bone sites including the elbow, total femur, hip, knee, and femoral mid-shaft. Also, the NO-containing diet was effective in preventing loss of bone mineral density of the tibia. Although the NO-containing diet seemed to have a positive effect on long bones, it did not demonstrate similar effects in the vertebrae. This suggests that NO primarily affects cortical bone. The benefits seen with the natural oryzanol were not seen with the crystalline or solubilized oryzanol. One explanation might be that the natural oryzanol was absorbed more effectively than the crystalline and solubilized oryzanol. Another reason could be that the benefits of the NO diet are due to other components of the unsaponifiable fraction of rice bran oil. Rice bran oil, fed as a sole source of dietary fat reduced bone loss in long bones of ovariectomized rats suggesting there may be beneficial effects in humans.
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Colona, Heather Compton, "The effects of oryzanol on bone mineral density in ovariectomized, retired breeder rats" (2002). LSU Master's Theses. 3316.