Cobalamin and folate intake by pregnant women: its relationship to homocysteine metabolism and to polymorphism in methionine synthase, methylenetetrahydrofolate reductase and methionine synthase reductase genes

Author(s)

Perla Menezes Pereira

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2007-02-15

Examining board members

Elvira Maria Guerra Shinohara; Fabíola Attié de Castro; Rosário Dominguez Crespo Hirata

• Advisor: Elvira Maria Guerra Shinohara

Abstract

The inadequate intake of cobalamin and folate associated to polymorphisms in key-enzyme genes of homocysteine can worsen comorbidities related to the deficiency of these vitamins. The aims of this study were to evaluate the intake of cobalamin, foiate and vitamin 86 by pregnant women through three 24-hour dietary recaIl (IR24h); to assess the correlation between serum concentrations of folate, cobalamin, methionine, S-adenosilmethionine (SAM), S-adenosilhomocysteine (SAH), total homocysteine (tHcy) and methylmalohic acid (MMA)towards vitamins and proteins intaked by women, to analyze association between MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G polymorphisms and changes on vitamin and metabolites concentration, and to determine the nutritional and genetic determinants during a gestational period. 73 pregnant women participated in this study, with gestational ages of 16,28 and 36 weeks, onto whom were applied three IR24h to each woman, being one in each gestational age. Serum concentrations of cobalamin, foiate and red blood cell foiate, total homocysteine, methionine, MMA, SAM and SAH were evaluated. The polymorphisms of MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRRA66G were performed by PCR-RFLP. It was observed that folate intake was low in relationship to recommended value for pregnant women of 600 µg/day. Cobalamin intake was less than the one found in literature. Vitamin 86 and total protein intake was similar to the one found in literature. Serum Cbl concentrations were directly related to protein intake. MMA concentrations were in,verselycorrelated to cobalamin intake, to total proteins intakes and mounth per capita income. There were reduction of serum cobalamin concentration and enhance of MMAthroughout pregnancy weeks, being observed higher serum concentration of MMAamongst women that intaked less cobalamin. There was no association between MTHFRA1298Cand RRA66Gpolymorphism and the change in vitamins and metabolites concentrations. The women carrying allele 2756G for MTR polymorphism presented lesser serum methionine concentrations and alieie 677T for MTHFR C677T had less concentration of red blood cell folate. The red blood cell folate concentrations, intake of total proteins, serum creatinine concentrations and intake of vitamin 86 were eterminant of tHcy concentration. Serum creatinine was responsible for SAMconcentrations variability. Higher concentrations of serum foiate and lesse r concentrations of serum creatinine were responsible for the enhance of SAM/SAHvalues. The higher concentrations of MMAwere attributed to lesse r cobalamin intake, to lower per capita income and to lesser seruro concentration Df coba}amin. ConcJusions: lo/ate intake was less than ha(f of recommended amount, and cobalamina intake reached the recommended amount, however this amount was not enough to keeping the maternal metabolism. The poly~orphisms were not associated to low vitamin intake for explaining the changes Inserum concentrationsof tHcy,SAM,SAM/SAHand MMA. (AU)