Dietary recommendations and r and omized trials on vitamin D supplementation should evaluate whether increases in circulating 25-hydroxyvitamin D levels match expectations -- for instance , the average increases obtained by trials on vitamin D3 without concomitant calcium supplements
CONTEXT Few studies in subjects over 50 yr of age have evaluated the influence of variable doses of vitamin D supplementation on serum 25-hydroxyvitamin D levels .
OBJECTIVE We performed a meta- analysis of changes in circulating 25-hydroxyvitamin D level associated with vitamin D supplementation in Caucasian subjects over 50 yr old .
Long-term effects of nutrient intervention on markers of bone remodeling and calciotropic hormones in late-postmenopausal women.
BACKGROUND Adequate intakes of calcium and vitamin D reduce bone loss and fracture risk in the elderly . Other nutrients also affect bone health , and adequate intakes may influence bone turnover and balance . OBJECTIVE We compared the long-term effects on bone turnover markers and calciotropic hormones of a multinutrient supplement , a calcium and vitamin D supplement , and dietary instruction aim ed at increasing calcium intake through foods . DESIGN Ninety-nine healthy postmenopausal women participated in a 3-y , r and omized trial , receiving either 1 ) supplemental calcium ( 1450 mg/d ) and vitamin D [ 10 microg ( 400 IU)/d ] , 2 ) calcium , vitamin D , and other nutrients ( multinutrient supplement ) , or 3 ) dietary instruction ( dietary control group ) . Data are from 83 subjects who completed the trial . RESULTS Increases over baseline in calcium intakes and serum 25-hydroxyvitamin D concentrations were sustained over 3 y in all treatment groups . Circulating parathyroid hormone concentrations were reduced at year 1 in all treatment groups but trended toward baseline thereafter . Bone turnover markers followed a similar pattern , and none of the changes in biochemical concentrations differed significantly between groups . CONCLUSIONS All 3 interventions offer long-term feasibility for increasing calcium intake and serum 25-hydroxyvitamin D concentrations . The dietary addition of micronutrients implicated in skeletal physiology confers no obvious bone-sparing effect in healthy postmenopausal women beyond that of calcium and vitamin D alone . The attenuation over time in suppression of parathyroid hormone and bone turnover might help explain why nutrient intervention tends to have less of a bone-sparing effect than do skeletally active medications such as estrogen or bisphosphonates
Dietary recommendations and r and omized trials on vitamin D supplementation should evaluate whether increases in circulating 25-hydroxyvitamin D levels match expectations -- for instance , the average increases obtained by trials on vitamin D3 without concomitant calcium supplements
CONTEXT Few studies in subjects over 50 yr of age have evaluated the influence of variable doses of vitamin D supplementation on serum 25-hydroxyvitamin D levels .
OBJECTIVE We performed a meta- analysis of changes in circulating 25-hydroxyvitamin D level associated with vitamin D supplementation in Caucasian subjects over 50 yr old .