Calcium and vitamin D controversies

Black tea may be a prospective adjunct for calcium supplementation to prevent early menopausal bone loss in a rat model of osteoporosis

The present study was undertaken to find out the ability of black tea extract (BTE) as a suitable alternative of adjunct for calcium supplementation in treating an ovariectomized rat model of early osteoporosis. Female Wistar rats weighing 140-150 g were divided into four groups consisting of six animals in each group: (A) sham-operated control; (B) bilaterally ovariectomized; (C) bilaterally ovariectomized + BTE; (D) bilaterally ovariectomized + 17 β -estradiol. Results suggest that BTE could promote intestinal absorption of calcium significantly (P < 0.01 for duodenum and ileum; and P < 0.05 for jejunum). This was found associated with enhanced activities of two relevant intestinal mucosal enzymes alkaline phosphatase (P < 0.01 for duodenum, jejunum, and ileum) and Ca(2+) activated ATPase (P < 0.01 for duodenum, jejunum, and ileum). Such BTE-mediated promotion of calcium absorption was coupled with increase in serum estrogen titer (P < 0.01) and recovery of all urinary, bone, and serum osteoporotic marker parameters, including bone histological features. Serum parathyroid hormone level, however, was not altered in these animals (P > 0.05). A comparative study with 17 β -estradiol, a well-known adjunct for calcium supplementation, indicated that efficacy of BTE in maintaining skeletal health is close to that of 17 β -estradiol. This study suggests that simultaneous use of BTE is promising as a prospective candidate for adjunctive therapies for calcium supplementation in the early stage of menopausal bone changes.