Bonjour JP , Benoit V , Payen F , Kraenzlin M. - 44392 N - J Clin Endocrinol Metab 2013 ; 98(7) : 2915-21.

Consumption of yogurts fortified in vitamin D and calcium reduces serum parathyroid hormone and markers of bone resorption: a double-blind randomized controlled trial in institutionalized elderly women

Context:Nutritional prevention of bone deterioration with fortified foods seems particularly suitable in institutionalized elderly women at risk of vitamin D deficiency, secondary hyperparathyroidism, increased bone resorption and osteoporotic fracture.Objective:To evaluate whether fortification of yogurts with vitamin D and calcium exerts an additional lowering effect on serum parathyroid hormone (PTH) and bone resorption markers (BRM) as compared to iso-caloric and iso-protein dairy products in elderly women.Design:A randomized double-blind controlled trial, 56-d intervention was conducted in institutionalized women (mean age 85.5 yr) consuming two 125 g servings of either vitamin D and calcium-fortified yogurts (FY) at supplemental levels of 10 mug vitamin D3/d and calcium 800 mg/d, or non fortified control yogurts (CY) providing 280 mg/d of calcium.Main Outcomes:The endpoints were serum changes from baseline (D0) to D28 and D56 in 25-hydroxyvitamin-D (25OHD), PTH and in BRM: Tartrate-resistant-acid-phosphatase-isoform-5b (TRAP5b), the primary outcome, and carboxy-terminal-cross-linked-telopeptide of type-I-collagen (CTX).Results:At D56, serum 25OHD increased (mean+/-SEM) by 25.3+/-1.8 vs. 5.2+/-2.5 nmol/L in FY (n=29) and CY (n=27), respectively (P<0.0001). The corresponding changes in PTH were -28.6+/-7.2 vs. -8.0+/-4.3% (P=0.0003), TRAP5b -21.9+/-4.3 vs. 3.0+/-3.2% (P<0.0001), CTX -11.0+/-9.7 vs. -3.0+/-4.1% (P=0.0146), in FY and CY, respectively. At D28, these differences were less pronounced, but already significant for 25OHD, PTH and TRAP5b.Conclusions:This study in institutionalized elderly at high risk for osteoporotic fracture suggests that fortification of dairy products with vitamin D3 and calcium provides a greater prevention of accelerated bone resorption as compared to non-fortified equivalent foods.