Dietary Intake Adequacy and Food Sources of Nutrients Involved in the Methionine-Methylation Cycle in Women of Childbearing Age from the ANIBES Spanish Population

Growing evidence confirms choline as a critical perinatal nutrient. However, intake levels of choline and betaine among the Spanish fertile population remain unknown. Given their role in one-carbon metabolism with potential epigenetic effects, the aim of the present study was to evaluate the dietary intakes, their adequacy to existing guidelines and the main food sources together with other micronutrients involved in the methylation-methionine cycle (vitamin B6, folates and vitamin B12) in women of childbearing age. The ANIBES study, a cross-sectional study of a representative sample of women of childbearing age (18-45 years, n = 641) resident in Spain, was used. The sample was divided into younger women (18-30 years, n = 251) and older women (31-45 years, n = 390). Dietary intake was assessed by a three-day dietary record by using a tablet device. Total median intakes for the total sample were 303.9 mg/d for choline; 122.6 mg/d for betaine; 1.3 mg/d for vitamin B6; 140.8 μg/d for folates, and 3.8 μg/d for vitamin B12. The older subgroup showed significantly higher choline (p < 0.05), betaine (p < 0.001) and folates (p < 0.05) intakes than younger women. Main food sources for the whole sample were meat and meat products for choline (28.3%), vitamin B6 (25.7%) and vitamin B12 (22.8%); cereals and derivatives (79.9%) for betaine; vegetables (20.0%) for folates. Overall intake adequacy was only observed for vitamin B12, with a very limited number of participants showing adequate intakes for all the other micronutrients. These results illustrate there is a relevant need to raise awareness about optimizing the status of the methionine cycle-related vitamins and cofactors in this potentially vulnerable population.

[Quantification, dietary intake adequacy, and food sources of nutrients involved in the methionine-methylation cycle (choline, betaine, folate, vitamin B6 and vitamin B12) in pregnant women in Spain]

OBJECTIVE

a quantification of dietary intakes of the micronutrients involved in the methylation-methionine cycle (choline, betaine, folate, vitamins B6 and B12) in a representative sample of pregnant women in Spain; assessment of intake adequacy to available official recommendations; and analysis of their main food sources.

MATERIAL AND METHODS

the median intake of each micronutrient was established using food consumption data reported in the National Dietary Survey of adults, the elderly, and pregnant women (ENALIA-2) (n = 133). For folate, vitamin B6 and vitamin B12 intake, nutritional composition data from the Spanish Food Composition Tables were used, whereas for choline and betaine, which are not included in European food composition databases, the National Nutrient Database for Standard Reference of the United States Department of Agriculture (USDA) was considered. Intake adequacy was estimated in accordance with the recommendations of the main Spanish, European, and US guidelines.

RESULTS

mean daily intakes observed were 271.1 mg/day of choline; 142.5 mg/day of betaine; 182.8 μg/day of folate; 1.4 mg/day of vitamin B6; and 4.5 μg/day of vitamin B12. Intake adequacy levels were insufficient for choline (< 60.2 %) and folate (< 30.5 %); close to adequacy for vitamin B6 (> 71.6 %); and fully adequate only in the case of vitamin B12 (> 101.1 %). It is not possible to draw any conclusions regarding betaine intake in the absence of established recommendations. Main food sources included foods of animal origin for choline and vitamin B12 (71.8 % and 97.4 %, respectively); cereals and derivatives for betaine (85.3 %); vegetables (27.5 %) together with cereals and derivatives (18.6 %) for folate; and meats and derivatives (26.6 %) followed by vegetables (17.9 %) for vitamin B6.

CONCLUSIONS

these findings are clearly indicative of the need to improve the intake and nutritional status of these components, which are of great nutritional interest for the health of pregnant women and, consequently, of their offspring. Consequent to the degree of adequacy observed, it seems necessary and urgent to employ not only dietary improvement strategies and the use of fortified foods, but also nutritional supplements with an individualized approach.

The role of Vitamin B12 and genetic risk factors in the etiology of neural tube defects: A systematic review

Neural tube defects (NTDs) are birth defects that arise during embryogenesis when normal neural tube closure fails to occur. According to the World Health Organization, NTDs are detected annually in approximately 300,000 neonates worldwide. The exact etiology of NTDs remains complex and poorly understood. It is generally agreed that most NTD cases are of multifactorial origin, having a combination of multiple genes and a number of environmental risk factors. The role of folic acid, vitamin B12 deficiency, genetics and other risk factors, in the etiology of NTDs, has also been extensively studied. This knowledge synthesis brings together different types of evidence to update the role of vitamin B12 deficiency, genetics and other risk factors, in the etiology of NTDs. Following a PubMed search and screening for relevant articles, we included 40 studies in our review (30 case-control studies, 3 cross-sectional studies, 5 cohort studies, and 2 case reports). The available data showed that vitamin B12 levels were decreased in mothers and infants in NTD groups compared with control groups. Holo-transcobalamin, the active form of vitamin B12, was also found in lower levels in mothers with NTD-affected infants. Several studies reported elevated homocysteine levels in mothers and infants in NTD groups. Additionally, numerous studies reported links between genetic variants and increased NTD risk. These genes include GIF, LRP2, CUBN, TCb1R, MTHFR, and others. Several maternal factors have also been linked with significant NTD risk such as BMI, maternal diet, air pollutants, low maternal age, and many others. The majority of studies on NTDs have focused on the role of folic acid, hence there is a need for well-designed studies on the role of other risk factors like vitamin B12 deficiency in the etiology of NTDs.

Maternal biomarkers for early prediction of the neural tube defects pregnancies

BACKGROUND

Neural tube defects (NTD) are one of the most common congenital birth defects. The reason for the NTD cause is still not completely known, but it is believed that some genetic and environmental factors might play a role in its etiology. Among the genetic factors the polymorphism in the folate gene pathway is crucial. Numerous studies have suggested the possible role of maternal higher plasma concentration of homocysteine and low concentration of folate and cobalamin in the development of NTD but some negative studies are also published.

AIM

Aim of the present was to find out the exact relation between NTD and maternal biomarkers like folate, cobalamin and homocysteine by conducting a meta-analysis.

METHOD

Different electronic databases were searched for the eligible studies. Standardized mean difference (SMD) with 95% confidence interval (CI) was used to determine association between maternal markers as risk for NTD pregnancy. The p value <0.05 was considered statistically significant in all tests. All the statistical analyses were done in the Open Meta-Analyst program.

RESULTS

The homocysteine is significantly associated with the increased risk of NTD (SMD = 0.57; 95% CI: 0.35-0.80, p = <0.001; I2 = 93.01%), s-folate showed protective role in NTD (SMD = -0.48; 95% CI: -0.77 to -0.19, p = 0.001; I2 = 95.73%), similarly cobalamin is also having protective role (SMD = -0.28; 95% CI: -0.43 to -0.13, p = <0.001; I2 = 80.40%).

CONCLUSION

In conclusion this study suggest that different maternal biomarkers may be used for the early prediction of the NTDs.

The correlation between methylenetetrahydrofolate reductase gene 677C > T polymorphism and fetal congenital defects: A meta-analysis

Objective To investigate the correlation between the methylenetetrahydrofolate reductase (MTHFR) gene 677C> T polymorphism and fetal congenital defects.

Method Original studies relevant to the MTHFR gene 677C>T single nucleotide polymorphism and fetal congenital defects were systematically searched in the electronic databases of Medline, EMBSE and China National Knowledge Infrastructure (CNKI). All relevant publications were screened for inclusion in the present work. The correlation between the MTHFR gene 677C > T single nucleotide polymorphism and the occurrence of fetal congenital defects was expressed as an odds ratio (OR) and its 95% confidence interval (95% CI). Publication bias was assessed by Begg’s funnel plot and Egger’s line regression test.

Results Nineteen case-control studies were ultimately included in the present meta-analysis. The pooled results indicated that the general risk of fetal congenital defects was significantly elevated in subjects with the 677T allele of the MTHFR gene in dominant (OR=1.07,95%CI:1.03-1.12, P<0.05), homozygous (OR=1.17,95%CI:1.06-1.30, P<0.05) and recessive genetic models (OR=1.16,95%CI:1.03-1.31, P<0.05) through the random effect method. However, significant publication bias was identified upon pooling the individual data and evaluating the correlation.

Conclusion According to the present evidence, the MTHFR gene 677C>T single nucleotide polymorphism is correlated with poor pregnancy outcomes, and subjects with the T allele have an increased risk of developing general fetal congenital defects.