Effect of isolated vitamin D supplementation on bone turnover markers in younger postmenopausal women: a randomized, double-blind, placebo-controlled trial.

Vitamin D (VD) plays an important role in bone mineralization. The present study investigates the effect of VD supplementation alone on bone turnover markers in younger postmenopausal women. It has been shown that VD supplementation in postmenopausal women with hypovitaminosis D is associated with a reduction in bone turnover markers. PURPOSE: The purpose of this study is to evaluate the effect of VD supplementation alone on bone turnover markers in younger postmenopausal women. METHODS: In this double-blind, placebo-controlled trial, 160 women were randomized into the VD group (supplementation with 1000 IU of vitamin D3/day, orally; n = 80) or placebo group (n = 80). Women aged 50-65 years with amenorrhea ≥ 12 months and normal bone mineral density were included. The intervention lasted 9 months, and the participants were assessed at the beginning and end of treatment. Serum levels of total calcium, parathormone (PTH), alkaline phosphatase (AP), and 24-h urine calcium were determined. Serum C-terminal telopeptide of type I collagen (s-CTX) and procollagen type 1 N-terminal propeptide (P1NP) were measured by immunoassay as markers of bone resorption and formation, respectively. Plasma 25-hydroxyvitamin-D [25(OH)D] concentrations were measured by HPLC. Intention-to-treat analysis was performed using ANOVA, Student's t test, Tukey's test, and gamma distribution. RESULTS: Over the period of 9 months, 25(OH)D concentrations increased from 15.0 ± 7.5 to 27.5 ± 10.4 ng/mL (+ 45.4%) in the VD group and decreased from 16.9 ± 6.7 to 13.8 ± 6.0 ng/mL (- 18.5%) in the placebo group (p < 0.001). There was a decrease (- 21.3%) of PTH levels in the VD group with a significant difference between groups at the end of the study (p < 0.001). No significant differences were observed in the other laboratory parameters (total calcium, AP, and calciuria) in either group (p > 0.05). A comparison of bone turnover markers showed a significant reduction in of s-CTX (- 24.2%, p < .0001) and P1NP (- 13.4%, p = 0.003) levels in the VD group. No significant variations in bone turnover markers were observed in the placebo group (s-CTX, - 6.9%, p = 0.092 and P1NP, - 0.6%, p = 0.918). CONCLUSION: In younger postmenopausal women with VD deficiency, isolated supplementation with 1000 IU of vitamin D3 for 9 months is associated with a reduction in bone turnover markers. However, any between-group differences was not observed in bone turnover markers.

Effects of omega-3 on metabolic markers in postmenopausal women with metabolic syndrome.

OBJECTIVE: The aim of this study was to evaluate the effect of diet alone or combined with omega-3 supplementation on metabolic and inflammatory markers in postmenopausal women with metabolic syndrome. METHODS: This randomized, controlled trial included 87 Brazilian women (age ≥ 45 years and with amenorrhea ≥ 12 months). Exclusion criteria were: cardiovascular disease, insulin-dependent diabetes, cancer, autoimmune diseases and use of either statins or hormone therapy. Participants were randomized to diet alone (n = 43, control) or diet plus omega-3 supplementation, 900 mg/day orally (n = 44). All women were provided with an individualized dietary prescription. Clinical, anthropometrical (body mass index and waist circumference) and biochemical variables were measured. The inflammatory profile included C-reactive protein, tumor necrosis factor α and interleukins (IL-1ß and IL-6). The intervention time was 6 months, with assessments at initiation and completion. Data were analyzed according to intention-to-treat, using the independent t-test and ANOVA. RESULTS: There were significant reductions in body mass index and waist circumference in both groups (p < 0.05) without significant changes in body fat or muscle mass. Intervention with diet plus omega-3 was associated with significant reduction in systolic (< 12.2%) and diastolic (< 8.2%) blood pressure, serum triglyceride concentration (< 21.4%), and insulin resistance (< 13.1%) (p < 0.05), as well as a reduction in serum IL-6 concentration (< 28.5%) (p = 0.034). CONCLUSION: In postmenopausal women with metabolic syndrome, dietary intervention plus supplementation of omega-3 resulted in a further decrease in triglycerides and blood pressure and also in an improvement in insulin resistance and inflammatory markers, important components of metabolic syndrome.