Grapefruit pulp increases antioxidant status and improves bone quality in orchidectomized rats.
Br J Nutr. 2007 Feb;97(2):365-72. PMID: 18595661
OBJECTIVE: Orchidectomy causes oxidative stress and increases the incidence of osteoporosis. The objective of this research was to evaluate whether eating grapefruit pulp (GP) modifies antioxidant status and reduces osteoporosis in orchidectomized rats. METHODS: Fifty-six 90-d-old male Sprague-Dawley rats were randomized into two groups: sham-control group (n = 14) and orchidectomized (ORX) group (n = 42). The orchidectomized group was equally divided among the following three treatments: orchidectomy, orchidectomy + 5.0% GP, and orchidectomy + 10% GP. At the termination of the study (day 60), all rats were euthanized and the plasma was collected for antioxidant status and indices of bone turnover. Bone quality and mineral contents in the bone, urine, and feces were evaluated. RESULTS: Orchidectomy lowered (P < 0.05) antioxidant status, bone quality, bone mineral contents and elevated (P < 0.05) indices of bone turnover, urinary deoxypyridinoline, and fecal calcium excretion. In contrast to the ORX group, independent of dosage, antioxidant status, bone density, and delayed time-induced femoral fracture were higher (P < 0.05) in the GP groups, whereas fecal calcium excretion and urinary deoxypyridinoline excretion were lowered (P < 0.05). GP dose-dependently slowed down bone turnover (P < 0.05), elevated bone calcium and magnesium contents (P < 0.05), tended to lower urinary excretion of magnesium, and numerically improved bone strength. CONCLUSION: The beneficial effects of eating red grapefruit on bone quality of ORX rats is due to bone mineral deposition and slowed-down bone turnover.