Background: Pregnancy and lactation in adolescents with habitually low calcium intake may adversely affect maternal bone mass. Objective: We investigated the effect of calcium plus vitamin D supplementation during pregnancy on bone mass during lactation in Brazilian adolescent mothers with low-calcium diets (w600 mg/d). Design: Pregnant adolescents (14-19 y) randomly received daily calcium (600 mg) plus vitamin D 3 (200 IU) (n = 30) or a placebo (n = 26) from 26 wk of pregnancy (baseline) until parturition. The bone mineral content (BMC), bone area (BA), and bone mineral density (BMD) at the total body, lumbar spine, and hip (total and femoral neck) were evaluated by using dual-energy X-ray absorptiometry at 5 and 20 wk postpartum. Serum hormones and 25-hydroxyvitamin D [25(OH)D] were measured. Group comparisons were adjusted for significant covariates. Results: The mean serum 25(OH)D concentration was 59 nmol/L at baseline. In comparison with the placebo, 25(OH)D tended to be 14-15 nmol/L higher postpartum in the supplemented group (P = 0.08). Total body and hip BMC and BMD decreased over time (P # 0.005) in both groups with a group 3 time interaction at the femoral neck (P , 0.04). Supplemented mothers had higher lumbar spine BA (6.7%; P = 0.002) and lumbar spine BMC (7.9%, P = 0.08) than did mothers who consumed the placebo at 5 wk postpartum. At 20 wk postpartum, differences between groups were more evident, with higher lumbar spine BMC (13.9%), lumbar spine BA (6.2%), and lumbar spine BMD (10.6%) in the supplemented group (P # 0.008). Conclusions: Calcium plus vitamin D supplementation during pregnancy of adolescents with low calcium intake results in higher lumbar spine bone mass and a reduced rate of femoral neck bone loss during lactation. Additional studies are required to determine whether bone effects are temporary or long-lasting. This trial was registered at clinicaltrials.gov as NCT01732328.Am J Clin Nutr 2013;98:82-91.

It appears that adolescent mothers with habitually low calcium intakes recover from lactation-associated bone loss after weaning. The rate of bone accretion, however, may not be sufficient to attain peak bone mass at maturity. Hormones regulating bone turnover during lactation may influence bone recovery in adolescent mothers.

Obesity is associated with hyperleptinemia and endothelial dysfunction. Hyperleptinemia has been reported to induce both oxidative stress and inflammation by increasing reactive oxygen species production. The objective of this study was to determine the effects of 1,25-dihydroxycholecalciferol [1,25(OH)D] against leptin-induced oxidative stress and inflammation in human endothelial cells. Small interfering RNA (siRNA) were used to knock down the expression of vitamin D receptor (VDR) in human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated for 4 h with physiologic (10 M) or supraphysiologic (10 M) concentrations of 1,25(OH)D and exposed to leptin (10 ng/mL). Superoxide anion production and translocation of nuclear factor (erythroid-derived 2)-like 2 (NRF2) and nuclear transcription factor κB (NF-κB) subunit p65 to the nucleus and the activation of their target genes were quantified. Pretreatment of HUVECs with 1,25(OH)D prevented the leptin-induced increase in superoxide anion production ( < 0.05). Pretreatment with 1,25(OH)D further increased NRF2 translocation to the nucleus (by 3-fold; < 0.05) and increased mRNA expression of superoxide dismutase 2 (; by 2-fold), glutathione peroxidase (; by 3-fold), NAD(P)H dehydrogenase (quinone) 1 (; by 4-fold), and heme oxygenase 1 (; by 2-fold) ( < 0.05). Leptin doubled the translocation of NF-κB ( < 0.05) to the nucleus and increased ( < 0.05) the upregulation of vascular inflammatory mediators such as monocyte chemoattractant protein 1 (; by 1-fold), transforming growth factor β ( β by 1-fold), and vascular cell adhesion molecule 1 (; by 4-fold) ( < 0.05), which were prevented ( < 0.05) by pretreatment with 1,25(OH)D Protective effects of 1,25(OH)D were confirmed to be VDR dependent by using VDR siRNA. Pretreatment with 1,25(OH)D in the presence of a high concentration of leptin has a beneficial effect on HUVECs through the regulation of mediators of antioxidant activity and inflammation.

Calcium and vitamin D supplementation of the adolescents studied resulted in higher fetal body weight at 36 wk of gestation and had no effect on infant bone mass at 5 wk postpartum. Because correlations between maternal and infant bone mass were evident only in the placebo group, infant bone mass appeared to be more dependent on maternal skeletal mass when calcium intake was low. This trial was registered at clinicaltrials.gov as NCT01732328.

This article aims to present methodological aspects on the collection, analyses, coverage, challenges, and the lessons learned from laboratory assessment of micronutrients on the Brazilian National Survey on Child Nutrition (ENANI-2019). This is a household survey on a probability sample of children under five years of age from 123 Brazilian municipalities in all 26 states and the Federal District. Blood samples were drawn by venipuncture at the homes of children 6 to 59 months of age. This procedure was performed by experienced phlebotomists from the laboratories located in the selected municipalities and scheduled in advance. Blood and serum levels were measured for biomarkers of nutritional status, using the services of a clinical test laboratory with nationwide coverage, for the following micronutrients: iron (hemoglobin and ferritin), zinc, selenium, folic acid, and vitamins A, B1, B6, B12, D, and E. C-reactive protein was analyzed as a marker of inflammation. A barcode identifier was used to track the blood samples and to link the biochemical test results to the other data collected in the survey. A total of 14,558 children were studied. Of the 12,598 eligible children, 8,829 (70.1%) had blood samples drawn. Of the total number of children who had samples drawn, 91.8% (n = 8,025) have results for at least nine of the 12 analyses performed. Coverage of the analysis varied from 95% (for vitamins A and E) to 84.2% (for folic acid). Aliquots of whole blood and serum were stored in a biorepository for future analyses. The results of this pioneering study in the country will back the formulation and, when necessary, the reorientation of public policies in food and nutrition.