Role of food fortification with vitamin D and calcium in the bone remodeling process in postmenopausal women: a systematic review of randomized controlled trials.

Context Foods containing vitamin D reduce the deficiency of this vitamin and improve bone turnover. Objective To discuss effects of the intake of vitamin D-fortified foods in isolated form or associated with calcium on bone remodeling in postmenopausal women. Data sources PubMed, Lilacs, Scopus, and Bireme databases. OpenThesis and Google Scholar were searched as grey literature. Medical subject headings or similar terms related to food fortified with vitamin D and bone in postmenopausal women were used. Data extraction Information was collected on study methodology and characteristics of studied populations; dosage; the food matrix used as the fortification vehicle; duration of intervention; dietary intake; 25-hydroxyvitamin D [25(OH)D] levels; serum parathyroid hormone (PTH) concentrations; bone resorption and/or formation markers (ie, carboxy terminal cross-linked telopeptide of type I collagen [CTX], tartrate-resistant acid phosphatase isoform 5b [TRAP5b], and procollagen type 1 N-terminal propeptide [P1NP]); main results; and study limitations. Data analysis Five randomized controlled trials involving postmenopausal women were included. The mean ages of participants ranged from 56.1 to 86.9 years. Daily consumption of soft plain cheese fortified with 2.5 µg of vitamin D3 and 302 mg of calcium for 4 weeks resulted in a mean increase of 0.8 ng/mL in 25(OH)D and 15.9 ng/mL in P1NP levels compared with baseline, and decreased CTX, TRAP5b, and PTH values. A similar intervention for 6 weeks, using fortified cheese, showed a reduction only in TRAP5b values (-0.64 U/L). Yogurt fortified with 10 µg of vitamin D3 and 800 mg of calcium did not change P1NP values after 8 weeks of intervention, but was associated with decreases of 0.0286 ng/mL and 1.06 U/L in PTH and TRAP5b, respectively. After 12 weeks of eating the fortified yogurt, 25(OH)D levels increased by a mean of 8.8 ng/mL and PTH levels decreased in by a mean of 0.0167 ng/mL. Conclusions The interventions contributed toward the improvement of the bone resorption process but not to the bone formation process in postmenopausal women. Prospero registration number CRD42019131976.