Collectively , these outcomes support a volumetric dilution of vitamin D. The slopes of the respective regression lines , however , indicate a smaller increase in 25OHD than would be expected from a direct mobilization of stores into the circulation .
Hence , sequestration of 25OHD and its conversion to inactive metabolites would also play a role .
The purpose of this review was to confirm a volumetric dilution of vitamin D in obesity .
It was based on the hypothesis that weight loss , particularly fat loss , would increase serum 25-hydroxyvitamin D ( 25OHD ) in the obese .
Bone minerals changes in obese women during a moderate weight loss with and without calcium supplementation.
A significant relationship between body weight ( BW ) and bone mass ( BM ) has been established previously . A diet-induced weight loss is accompanied by a significant decrease in bone mineral density ( BMD ) and total body bone mineral ( TBBM ) , but the underlying mechanisms are not clarified . Sixty-two obese women were included in the study .  Dual-energy X-ray absorptiometry ( DXA ) and measurements of a series of calcium-regulating hormones and biochemical markers of bone turnover were performed at baseline and after 1 month and 3 months on a low calorie diet . Thirty of the women were r and omized to a daily supplement of 1 g of calcium . After an additional 3 months without dietary prescriptions or calcium supplements , a subgroup of 48 subjects ( 24 from each group ) were scanned again using DXA . There was a significant decrease in TBBM after 1 month and 3 months . A similar pattern was observed in the bone mineral content ( BMC ) of the lumbar spine in the patients who did not receive a calcium supplement , whereas no changes occurred in the supplemented group . The initial calcium supplementation seemed to protect against bone loss in the lumbar spine but not in the TBBM . In the nonsupplemented group , a statistically significant inverse correlation was found between the calcium/creatinine ratio in the morning urine and the changes in BMC of the lumbar spine . Such a relationship was not seen in the calcium-supplemented group . In the nonsupplemented group , no significant biochemical changes were observed , whereas a significant decrease in serum parathyroid hormone ( PTH ) was seen in the calcium-supplemented group . This might explain some of the protective effects of calcium supplementation on trabecular bone mass . We conclude that a diet-induced weight loss is accompanied by a generalized bone loss , which probably is explained mainly by a reduced mechanical strain on the skeleton . This loss can be partly inhibited by a high calcium intake . Therefore , a calcium supplementation should be recommended during weight loss , even if the diet contains the officially recommended amounts of calcium
Collectively , these outcomes support a volumetric dilution of vitamin D. The slopes of the respective regression lines , however , indicate a smaller increase in 25OHD than would be expected from a direct mobilization of stores into the circulation .
Hence , sequestration of 25OHD and its conversion to inactive metabolites would also play a role .
The purpose of this review was to confirm a volumetric dilution of vitamin D in obesity .
It was based on the hypothesis that weight loss , particularly fat loss , would increase serum 25-hydroxyvitamin D ( 25OHD ) in the obese .