Vitamin D3 and B12 supplementation in pregnancy

An 8-Week Vitamin D3-Fortified Fruit Drink Supplementation Increases Serum Ferritin Concentration: A Randomized Controlled Trial in Malaysian Women With Low Iron Stores

BACKGROUND

There is limited randomized controlled trial evidence to support the association between vitamin D deficiency and anemia risk, highlighting the necessity for further investigations into the role of vitamin D in influencing iron status.

OBJECTIVE

The aim of this study was to determine the effect of vitamin D3-fortified fruit drink consumption (4,000 IU) on vitamin D and iron status biomarkers among iron-deficient women (serum ferritin of <20 μg/L [to convert μg/L ferritin to ng/mL, multiply by 1]).

DESIGN

An 8-week double-blind randomized controlled trial was conducted.

SUBJECTS/SETTING

A total of 45 healthy, nonpregnant, nonlactating subjects aged 18 through 40 years (mean [SD] 25.3 [4.6] years) were included in the study, excluding those who donated blood 6 months prior, regularly consumed nutritional supplements, or had gastrointestinal or iron metabolic disorders.

INTERVENTION

Subjects were randomly assigned to receive either vitamin D3-fortified fruit drink or a placebo.

MAIN OUTCOME MEASURES

Measurements of 25-hydroxyvitamin D (25[OH]D), serum ferritin, high-sensitivity C-reactive protein, and full blood count concentrations were obtained at baseline, interim, and post intervention.

STATISTICAL ANALYSES

A mixed model, repeated measures analysis of variance was used to analyze the intervention effect.

RESULTS

Attrition rate for the study was 13%, with 6 dropouts, and 39 subjects completed the study. Daily consumption of vitamin D3-fortified fruit drink in the intervention group resulted in significant increases in 25(OH)D and serum ferritin concentrations compared with the placebo group. The intervention group showed significantly higher mean (SD) changes (Δ) in both 25(OH)D (Δ 76.4 [30.2] nmol/L [to convert nmol/L 25(OH)D to ng/mL, multiply by .4] vs Δ -1.3 [10.7] nmol/L; P = .001) and serum ferritin concentrations (Δ 2.2 [4.2] μg/L vs Δ -0.3 [3.4] μg/L; P = .048) between baseline and post intervention. The other iron status biomarkers were not affected by the intervention.

CONCLUSIONS

Our study found that daily vitamin D3-fortified fruit drink supplementation for 8 weeks effectively improved 25(OH)D and iron stores, indicated by increased serum ferritin concentrations, in iron-deficient women. Further research is needed to evaluate its safety, efficacy, feasibility, and optimal food fortification in diverse populations.

Vitamin B12 supplementation during pregnancy for maternal and child health outcomes

BACKGROUND

Vitamin B12 deficiency is a major public health problem worldwide, with the highest burden in elderly people, pregnant women, and young children. Due to its role in DNA synthesis and methylation, folate metabolism, and erythropoiesis, vitamin B12 supplementation during pregnancy may confer longer-term benefits to maternal and child health outcomes.

OBJECTIVES

To evaluate the benefits and harms of oral vitamin B12 supplementation during pregnancy on maternal and child health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) on 2 June 2023, and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, or cluster-RCTs evaluating the effects of oral vitamin B12 supplementation compared to placebo or no vitamin B12 supplementation during pregnancy.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Four review authors independently assessed trial eligibility. Two review authors independently extracted data from included studies and conducted checks for accuracy. Three review authors independently assessed the risk of bias of the included studies using the Cochrane RoB 1 tool. We used GRADE to evaluate the certainty of evidence for primary outcomes.

MAIN RESULTS

The review included five trials with 984 pregnant women. All trials were conducted in low- and middle-income countries, including India, Bangladesh, South Africa, and Croatia. At enrolment, 26% to 51% of pregnant women had vitamin B12 deficiency (less than 150 pmol/L), and the prevalence of anaemia (haemoglobin less than 11.0 g/dL) ranged from 30% to 46%. The dosage of vitamin B12 supplementation varied from 5 μg/day to 250 μg/day, with administration beginning at 8 to 28 weeks' gestation through to delivery or three months' postpartum, and the duration of supplementation ranged from 8 to 16 weeks to 32 to 38 weeks. Three trials, involving 609 pregnant women, contributed data for meta-analyses of the effects of vitamin B12 supplementation compared to placebo or no vitamin B12 supplementation. Maternal anaemia: there may be little to no difference for maternal anaemia by intervention group, but the evidence is very uncertain (70.9% versus 65.0%; risk ratio (RR) 1.08, 95% confidence interval (CI) 0.93 to 1.26; 2 trials, 284 women; very low-certainty evidence). Maternal vitamin B12 status: vitamin B12 supplementation during pregnancy may reduce the risk of maternal vitamin B12 deficiency compared to placebo or no vitamin B12 supplementation, but the evidence is very uncertain (25.9% versus 67.9%; RR 0.38, 95% CI 0.28 to 0.51; 2 trials, 272 women; very low-certainty evidence). Women who received vitamin B12 supplements during pregnancy may have higher total vitamin B12 concentrations compared to placebo or no vitamin B12 supplementation (mean difference (MD) 60.89 pmol/L, 95% CI 40.86 to 80.92; 3 trials, 412 women). However, there was substantial heterogeneity (I2 = 85%). Adverse pregnancy outcomes: the evidence is uncertain about the effect on adverse pregnancy outcomes, including preterm birth (RR 0.97, 95% CI 0.55 to 1.74; 2 trials, 340 women; low-certainty evidence), and low birthweight (RR 1.50, 95% CI 0.93 to 2.43; 2 trials, 344 women; low-certainty evidence). Two trials reported data on spontaneous abortion (or miscarriage); however, the trials did not report quantitative data for meta-analysis and there was no clear definition of spontaneous abortion in the study reports. No trials evaluated the effects of vitamin B12 supplementation during pregnancy on neural tube defects. Infant vitamin B12 status: children born to women who received vitamin B12 supplementation had higher total vitamin B12 concentrations compared to placebo or no vitamin B12 supplementation (MD 71.89 pmol/L, 95% CI 20.23 to 123.54; 2 trials, 144 children). Child cognitive outcomes: three ancillary analyses of one trial reported child cognitive outcomes; however, data were not reported in a format that could be included in quantitative meta-analyses. In one study, maternal vitamin B12 supplementation did not improve neurodevelopment status (e.g. cognitive, language (receptive and expressive), motor (fine and gross), social-emotional, or adaptive (conceptual, social, practical) domains) in children compared to placebo (9 months, Bayley Scales of Infant and Toddler Development Third Edition (BSID-III); 1 trial; low-certainty evidence) or neurophysiological outcomes (72 months, event-related potential measures; 1 trial; low-certainty evidence), though children born to women who received vitamin B12 supplementation had improved expressive language domain compared to placebo (30 months, BSID-III; 1 trial; low-certainty evidence).

AUTHORS' CONCLUSIONS

Oral vitamin B12 supplementation during pregnancy may reduce the risk of maternal vitamin B12 deficiency and may improve maternal vitamin B12 concentrations during pregnancy or postpartum compared to placebo or no vitamin B12 supplementation, but the evidence is very uncertain. The effects of vitamin B12 supplementation on other primary outcomes assessed in this review were not reported, or were not reported in a format for inclusion in quantitative analyses. Vitamin B12 supplementation during pregnancy may improve maternal and infant vitamin B12 status, but the potential impact on longer-term clinical and functional maternal and child health outcomes has not yet been established.

Babies of South Asian and European Ancestry Show Similar Associations With Genetic Risk Score for Birth Weight Despite the Smaller Size of South Asian Newborns

Size at birth is known to be influenced by various fetal and maternal factors, including genetic effects. South Asians have a high burden of low birth weight and cardiometabolic diseases, yet studies of common genetic variations underpinning these phenotypes are lacking. We generated independent, weighted fetal genetic scores (fGSs) and maternal genetic scores (mGSs) from 196 birth weight-associated variants identified in Europeans and conducted an association analysis with various fetal birth parameters and anthropometric and cardiometabolic traits measured at different follow-up stages (5-6-year intervals) from seven Indian and Bangladeshi cohorts of South Asian ancestry. The results from these cohorts were compared with South Asians in UK Biobank and the Exeter Family Study of Childhood Health, a European ancestry cohort. Birth weight increased by 50.7 g and 33.6 g per SD of fGS (P = 9.1 × 10-11) and mGS (P = 0.003), respectively, in South Asians. A relatively weaker mGS effect compared with Europeans indicates possible different intrauterine exposures between Europeans and South Asians. Birth weight was strongly associated with body size in both childhood and adolescence (P = 3 × 10-5 to 1.9 × 10-51); however, fGS was associated with body size in childhood only (P < 0.01) and with head circumference, fasting glucose, and triglycerides in adults (P < 0.01). The substantially smaller newborn size in South Asians with comparable fetal genetic effect to Europeans on birth weight suggests a significant role of factors related to fetal growth that were not captured by the present genetic scores. These factors may include different environmental exposures, maternal body size, health and nutritional status, etc. Persistent influence of genetic loci on size at birth and adult metabolic syndrome in our study supports a common genetic mechanism that partly explains associations between early development and later cardiometabolic health in various populations, despite marked differences in phenotypic and environmental factors in South Asians.