Excessive
iron consumption during pregnancy can lead to increased oxidative stress in the maternal body, which may result in adverse pregnancy outcomes.
Glutathione S-
transferases (
GSTs) originate from a superfamily of detoxifying
enzymes that play a role in reducing
xenobiotic compounds and oxidative stress. The aim of this study was to determine the relationship among GST gene expression, maternal
iron intake during pregnancy, and neonatal
birth weight. The study participants were 1087 Korean gravidas and their newborns recruited for the Mothers and Children's Environmental Health study between 2006 and 2010. A 24-h dietary recall interview was conducted to estimate
iron intake; additional intake through nutritional supplements was thoroughly investigated. Deletion polymorphisms of GSTM1 and GSTT1 were genotyped using PCR.
Dietary iron consumption during pregnancy was positively associated with
birth weight in pregnant women who were GSTM1-present after adjustment for the following covariates: maternal age, prepregnancy BMI, mother's education level, log-transformed urinary
cotinine level, infant gender, gestational age at term, log-transformed energy intake, parity, and the use of
folic acid supplements (P < 0.05). There were interactions between the GSTM1 genotype and
iron intakes from animal foods (P < 0.05), diet (P < 0.05), and diet with supplements (P < 0.05). No relationship was found between maternal
iron intake and
birth weight for the GSTT1 polymorphism. This study demonstrates that increased
iron consumption during pregnancy may improve infant
birth weight for mothers who are GSTM1-present, but it might not be beneficial for mothers with the GSTM1-null genotype.