Dietary and genetic determinants of homocysteine levels among Mexican women of reproductive age

Abstract

Objective: To evaluate the independent and joint effects of dietary folate, vitamin B 12 consumption and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (677C4T and 1298A4C) on the circulating folate and homocysteine (Hcy) levels among Mexican women of reproductive age. Design: A cross-sectional, population-based study. Subjects: The first 130 healthy non-pregnant women (aged 16-34 years) who agreed to participate in a reproductive cohort in Morelos, Mexico. Main outcome measurements: Dietary intakes of vitamin B 12 and folate were estimated using a semiquantitative food frequency questionnaire. MTHFR 677C4T and 1298A4C polymorphisms were ascertained using the PCR-based method. Serum levels of Hcy and folate were determined using high-performance liquid chromatography and radioimmunoassay, respectively. Results: Genotype frequencies for the MTHFR 677C4T polymorphism were 21.5% (CC), 52.3% (CT) and 26.2% (TT) among Mexican women. Of the population, 22% had the MTHFR 1298AC genotype, while no individual carried the 1298CC genotype. We observed an increased level of Hcy among carriers of the 677TT genotype, compared to carriers of the 677CC genotype. The highest level of Hcy was observed among MTHFR 677TT carriers with low B 12 intake (o2.0 mg/day), which resulted with a significant interaction (P ¼ 0.01).

Maternal dietary intake of folate, vitamin B12 and MTHFR 677C>T genotype: their impact on newborn’s anthropometric parameters

“…According to estimates by the National Nutrition Survey, in Mexico, 34.7 % of women aged 12-49 years have an inadequate consumption of folate (Barquera et al 2003). Although there is no information about the deficiency of vitamin B 12 intake at the population level, in previous reports with non-pregnant women of reproductive age in the same population, we found a dietary vitamin B 12 deficiency of 15.4 % (Torres- Sánchez et al 2006) and 21.3 % of pregnant women during the first trimester of pregnancy (Del Río-García et al 2009). …”

“…Dietary sources of vitamin B 12 included: liver, sardines, tuna, pork, lamb, beef, dairy, eggs, fish, chocolate, beer and white and red wines. This methodology is described in two previous studies where we used this program (Torres-Sánchez et al 2006;Del Río-García et al 2009). …”

Prenatal dichlorodiphenyldichloroethylene (DDE) exposure and child growth during the first year of life

“…The frequency of consumption of 95 items with predetermined portions was classified according to 10 response categories, going from ‘never’ up to ‘six times per day’. Nutrient intake including folate, vitamin B 12 , calcium, iron and zinc was estimated through a computer program developed by the University of Texas (Food Intake Analysis System [FIAS] 3.0) and used previously in other similar populations (Torres et al, 2006; López-Carrillo et al, 1999). More details on the methodology are available elsewhere (Río García et al, 2009).…”

Assessing the association between the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism and blood folate concentrations: a systematic review and meta-analysis of trials and observational studies

“…Of the remaining 38 studies, 7 studies reported using MAs, 28 reported using PBAs (e.g., chemiluminescent immunoassay), 1 reported use of both a PBA and LC-MS/MS to measure plasma folate and RBC folate, respectively (50), and 2 did not report assay method used (48,51). The 2 unknown assay studies and 3 PBA studies that specifically used the BRQ II RIA (52)(53)(54) were restricted to tier 2 analyses. In the case of the study that used 2 methods, RBC folate values were not used in meta-analyses because it was the only study to use LC-MS/MS (50).…”