Long-term effects of nutrient intervention on markers of bone remodeling and calciotropic hormones in late-postmenopausal women

Abstract

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 aimed at increasing calcium intake through foods. Design: Ninety-nine healthy postmenopausal women participated in a 3-y, randomized trial, receiving either 1) supplemental calcium (1450 mg/d) and vitamin D [10 μg (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.