Supplementation with (6S)-5-methyltetrahydrofolic acid appears as effective as folic acid in maintaining maternal folate status while reducing unmetabolised folic acid in maternal plasma: a randomised trial of pregnant women in Canada.

Folic acid supplementation is recommended during pregnancy to support healthy fetal development; (6S)-5-methyltetrahydrofolic acid ((6S)-5-MTHF) is available in some commercial prenatal vitamins as an alternative to folic acid, but its effect on blood folate status during pregnancy is unknown. To address this, we randomised sixty pregnant individuals at 8-21 weeks' gestation to 0·6 mg/d folic acid or (6S)-5-MTHF × 16 weeks. Fasting blood specimens were collected at baseline and after 16 weeks (endline). Erythrocyte and serum folate were quantified via microbiological assay (as globally recommended) and plasma unmetabolised folic acid (UMFA) via LC-MS/MS. Differences in biochemical folate markers between groups were explored using multivariable linear/quantile regression, adjusting for baseline concentrations, dietary folate intake and gestational weeks. At endline (n 54), the mean values and standard deviations (or median, inter-quartile range) of erythrocyte folate, serum folate and plasma UMFA (nmol/l) in those supplemented with (6S)-5-MTHF v. folic acid, respectively, were 1826 (sd 471) and 1998 (sd 421); 70 (sd 13) and 78 (sd 17); 0·5 (0·4, 0·8) and 1·3 (0·9, 2·1). In regression analyses, erythrocyte and serum folate did not differ by treatment group; however, concentrations of plasma UMFA in pregnancy were 0·6 nmol/l higher (95 % CI 0·2, 1·1) in those supplementing with folic acid as compared with (6S)-5-MTHF. In conclusion, supplementation with (6S)-5-MTHF may reduce plasma UMFA by ∼50 % as compared with supplementation with folic acid, the biological relevance of which is unclear. As folate is currently available for purchase in both forms, the impact of circulating maternal UMFA on perinatal outcomes needs to be determined.

Human milk oligosaccharide composition following supplementation with folic acid vs (6S)-5-methyltetrahydrofolic acid during pregnancy and mediation by human milk folate forms.

Supplementation with folic acid versus (6S)-5-methyltetrahydrofolic acid (5-MTHF) results in different folate forms in human milk, with folic acid increasing unmetabolized folic acid (UMFA) at the expense of reduced folate forms. It is unknown whether folate forms present in human milk have further effects on human milk composition, such as human milk oligosaccharide (HMO) concentrations. We randomized 60 pregnant women in Canada to 0.6 mg/day folic acid or (6S)-5-MTHF. Human milk folate forms (LC-MS/MS) and nineteen HMOs (HPLC) were quantified at 1 week postpartum. Linear regression and causal mediation analysis were used to evaluate the effect of folate supplementation on HMO concentrations, and possible mediation by concentrations of UMFA and reduced folate forms in human milk (controlling for secretor status and parity). HMO concentrations were not different between groups, with no evidence of mediation by reduced folate forms; however, increased UMFA was associated with reduced concentrations of total HMOs and 3'-sialyllactose.

Optimizing vitamin D status in polycystic ovary syndrome: a systematic review and dose-response meta-analysis.

CONTEXT: Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder in women of reproductive age. Vitamin D supplementation is a promising complementary therapy for PCOS, yet there is no consensus on an optimal dose, leading to a lack of evidence-based supplementation guidelines. OBJECTIVE: The objective of this study was to conduct a vitamin D dose-response meta-analysis among women with PCOS. DATA SOURCES: MEDLINE, CINAHL, and EMBASE databases from inception to November 2022 were searched for relevant articles. DATA EXTRACTION: Study screening and bias assessment were conducted by 2 independent reviewers. Eight relevant studies were identified; data for serum 25(OH)D (nmol/L) at baseline and at 12 weeks in each intervention group (mean ± SD) and vitamin D dose were extracted. DATA ANALYSIS: Estimates across studies were used to create a pooled curve, using restricted cubic splines with knots at the 10th, 50th, and 90th percentiles of the distribution of doses, to estimate the mean difference in effect for serum 25(OH)D at each dose compared with 0 IU/day. Sensitivity analyses were conducted fixing knots at 4000 IU/day and 7000 IU/day, which were a priori identified as potentially important thresholds, and to assess model fit and estimate heterogeneity. The pooled analysis demonstrated strong evidence of a dose-response relationship (P < .001), suggesting an increasing effect with increasing dose. An initial increase in serum 25(OH)D was evident until doses of approximately 3000 IU/day; this was followed by a plateau in effect between approximately 3000 IU/day and 5000 IU/day. The effect of supplementation with >5000 IU/day was unclear, given the minimal data at higher doses. The curve produced robust results for moderate doses (3000 IU/day to 4000 IU/day), which were not sensitive to model specification. CONCLUSION: Women with PCOS are responsive to vitamin D supplementation, but the benefit of providing doses of >3000 IU/day appears minimal. Further data is required to determine dose-response at doses of >5000 IU/day, and whether higher intakes provide a clinically meaningful advantage in this population. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021259396.

Human milk unmetabolized folic acid is increased following supplementation with synthetic folic acid as compared to (6S)-5-methyltetrahydrofolic acid.

Folic acid supplementation is recommended perinatally, but may increase unmetabolized folic acid (UMFA) in human milk; this is concerning as it is an inactive form which may be less bioavailable for the infant. "Natural" (6S)-5-methyltetrahydrofolic acid [(6S)-5-MTHF] is available as an alternative to folic acid, and may prevent the accumulation of UMFA in human milk. Pregnant women (n = 60) were enrolled at 8-21 weeks of gestation and randomized to 0.6 mg/day folic acid or (6S)-5-MTHF. At ~ 1-week postpartum, participants provided a human milk specimen. Total human milk folate (nmol/L) and concentrations of UMFA (nmol/L) were quantified via LC-MS/MS. Differences between groups were evaluated using multivariable quantile/linear regression, adjusting for dietary folate, weeks supplementing, and milk collection methods. No significant difference in total milk folate was found; however, the median milk UMFA concentration was 11 nmol/L higher in those receiving folic acid versus (6S)-5-MTHF (95% CI = 6.4-17 nmol/L), with UMFA representing 28% and 2% of total milk folate. In conclusion, the form of supplemental folate had markedly differential effects on the human milk folate profile, with folic acid increasing the mean proportion of milk UMFA by ~ 14-fold. Investigation of whether increased UMFA impacts folate-related metabolism and infant health outcomes is required.

Iron-Deficiency Prevalence and Supplementation Practices Among Pregnant Women: A Secondary Data Analysis From a Clinical Trial in Vancouver, Canada.

BACKGROUND: North American public health guidelines recommend supplementation with an iron-containing prenatal multivitamin throughout pregnancy to meet the RDA of 27 mg of elemental iron daily. However, whether supplementation with standard prenatal multivitamins is sufficient to prevent maternal iron deficiency is unclear, as needs increase substantially with advancing gestation. OBJECTIVES: This study aimed to assess iron status in early and late pregnancy among 60 pregnant women receiving 27 mg/day of elemental iron as part of a randomized trial in Vancouver, Canada. METHODS: Study visits were conducted at 8-21 (baseline) and 24-38 (endline) weeks of gestation. Venous blood specimens were collected for a complete blood count and measurement of iron and inflammatory biomarkers. Supplementation with any additional iron (beyond 27 mg/day) was reported by participants (treatment with additional iron is recommended if ferritin is <30 µg/L). Quantile regression was used to explore predictors of endline ferritin concentrations, including ethnicity, education, income, and baseline ferritin measurement. RESULTS: Overall, 60 and 54 women participated in baseline and endline visits, respectively. Rates of probable iron deficiency (ferritin <30 µg/L) at baseline and endline were 17 (28%) and 44 (81%), respectively. Less than half (n = 18; 41%) of participants with probable iron deficiency at endline reported supplementation with additional iron. Ethnicity was the only significant modifier of endline ferritin, with higher concentrations in those of South, East, and Southeast Asian ethnicity compared to those of European ethnicity (ß: 10.4 µg/L; 95% CI: 0.3-20.5). CONCLUSIONS: Pregnant individuals may require additional supplemental iron beyond 27 mg to meet requirements in later pregnancy, given the high rates of iron deficiency observed in this clinical trial, despite consumption meeting 100% of the RDA. This trial was registered at clinicaltrials.gov as NCT04022135.

Pregnancy-induced alterations of 1-carbon metabolism and significance for maternal nutrition requirements.

OBJECTIVES: The pregnancy-induced alterations in 1-carbon (1C) metabolism, effects of advancing gestation on maternal plasma concentrations of methyl nutrients, and potential implications for maternal dietary intake and infant clinical outcomes are summarized in this narrative review. BACKGROUND: 1C metabolism encompasses a series of pathways where 1C units are transferred among nutrients such as B vitamins, choline, and amino acids (the methyl nutrients). Use of isotopic tracers and measuring methyl nutrients in maternal plasma and infant cord blood has advanced the understanding of 1C flux in pregnancy and kinetics of maternal-placental-fetal transfer. Methyl nutrients are supplied from maternal plasma to the placenta and fetus to support growth and 1C metabolism in these compartments. METHODS: A literature review was completed in MEDLINE and Google Scholar using search terms related to 1C metabolism, methyl nutrients, and nutrition requirements in pregnancy. English-language articles were reviewed in which 1C metabolism in pregnancy, maternal-placental-fetal transfer of methyl nutrients, and determinants of maternal plasma concentrations of methyl nutrients among healthy pregnant women were assessed. DISCUSSION: Adaptations in 1C metabolism occur throughout a healthy pregnancy to support this unique period of accelerated growth. Studies report similar temporal changes in plasma concentrations of many methyl nutrients, including B vitamins, choline, betaine, methionine, and cysteine, among healthy pregnant women from diverse geographic regions. Other key findings discussed in this review include an apparent high degree of B vitamin transfer to the placenta and fetus, influence of choline supplementation on 1C flux and possible benefit of supplementation for infant cognitive development, and that glycine may be conditionally essential in pregnancy. CONCLUSION: Understanding the flux of 1C metabolism in pregnancy and methyl nutrient transfer from maternal plasma is needed to establish appropriate plasma references ranges and, ultimately, dietary recommendations that aim to prevent deficiency and associated adverse health outcomes for mother and baby.

Regression to the Mean: A Statistical Phenomenon of Worthy Consideration in Anemia Research.

BACKGROUND: Regression to the mean (RTM) is a statistical phenomenon where second measurements are more likely to be closer to the mean. This is particularly observed in those with baseline values further from the mean. Anemic individuals (hemoglobin <120 g/L) are often recruited when evaluating iron supplementation programs, as they are more likely to elicit a greater hemoglobin response; however, they are also at greater risk for RTM as their baseline values are lower than the overall population mean. OBJECTIVE: The aim was to calculate and apply RTM to a previously conducted iron supplementation trial of women in Cambodia at increasingly severe baseline anemia cutoffs (hemoglobin <120 g/L, <115 g/L, and <110 g/L). METHODS: Women received either 60 mg/d iron (n = 191) or placebo (n = 185) for 12 wk. Hemoglobin was measured at baseline and at 12 wk (endline), and change in hemoglobin was calculated in each group for each cutoff. RTM was calculated in the placebo group at each cutoff and applied to the change observed at each cutoff in the iron group to obtain the RTM-free effect. RESULTS: In the placebo group, mean change in hemoglobin increased as cutoffs became more extreme (0.9 g/L to 1.9 g/L in those with baseline hemoglobin <120 g/L and <110 g/L, respectively). RTM estimates similarly increased: 1.0 g/L (<120 g/L), 1.3 g/L (<115 g/L), and 1.8 g/L (<110g/L). When applying RTM to the iron group, we found that ∼10% of the "treatment effect" could be attributable to RTM at each cutoff. However, iron supplementation was still effective in increasing hemoglobin, with an increased effect in those with lower baseline values, as proven by the RTM-free effect at each cutoff: 8.7 g/L (<120 g/L), 10.9 g/L (<115 g/L), and 13.6g/L (<110 g/L). CONCLUSIONS: RTM may have accounted for ∼10% of the observed change in hemoglobin following iron supplementation; however, appropriate use of a placebo group in the statistical analyses of the trial controls for this potential RTM effect.

Is natural (6S)-5-methyltetrahydrofolic acid as effective as synthetic folic acid in increasing serum and red blood cell folate concentrations during pregnancy? A proof-of-concept pilot study.

BACKGROUND: North American health authorities recommend 0.4 mg/day folic acid before conception and throughout pregnancy to reduce the risk of neural tube defects. Folic acid is a synthetic form of folate that must be reduced by dihydrofolate reductase and then further metabolized. Recent evidence suggests that the maximal capacity for this process is limited and unmetabolized folic acid has been detected in the circulation. The biological effects of unmetabolized folic acid are unknown. A natural form of folate, (6S)-5-methyltetrahydrofolic acid (Metafolin®), may be a superior alternative because it does not need to be reduced in the small intestine. Metafolin® is currently used in some prenatal multivitamins; however, it has yet to be evaluated during pregnancy. METHODS/DESIGN: This double-blind, randomized trial will recruit 60 pregnant women aged 19-42 years. The women will receive either 0.6 mg/day folic acid or an equimolar dose (0.625 mg/day) of (6S)-5-methyltetrahydrofolic acid for 16 weeks. The trial will be initiated at 8-21 weeks' gestation (after neural tube closure) to reduce the risk of harm should (6S)-5-methyltetrahydrofolic acid prove less effective. All women will also receive a prenatal multivitamin (not containing folate) to ensure adequacy of other nutrients. Baseline and endline blood samples will be collected to assess primary outcome measures, including serum folate, red blood cell folate and unmetabolized folic acid. The extent to which the change in primary outcomes from baseline to endline differs between treatment groups, controlling for baseline level, will be estimated using linear regression. Participants will have the option to continue supplementing until 1 week postpartum to provide a breastmilk and blood sample. Exploratory analyses will be completed to evaluate breastmilk and postpartum blood folate concentrations. DISCUSSION: This proof-of-concept trial is needed to obtain estimates of the effect of (6S)-5-methyltetrahydrofolic acid compared to folic acid on circulating biomarkers of folate status during pregnancy. These estimates will inform the design of a definitive trial which will be powered to assess whether (6S)-5-methyltetrahydrofolic acid is as effective as folic acid in raising blood folate concentrations during pregnancy. Ultimately, these findings will inform folate supplementation policies for pregnant women. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT04022135. Registered on 14 July 2019.