Epidemiological Study On Effect And Mechanism Of Low Glycemic Index Diet Intervention On Methylation Of Overweight Pregnant Women

Objective:To evaluate whether the low glycemic diet influence intervention during pregnancy to overweight pregnant women have any impact on DNA methylation in placenta tissue and cord blood of their neonates and the nutritional status of pregnancy women.M ethods Randomized, single blinded, congtrolled intervention trial was selecteded. Overweight pregnant women(BMI≥24kg/m2) were recruited at first prenatal visit within12gastational weeks.Subjects were randomized and allocated into two groups,intervention group and control group.The intervention group was provided3times diet consultation about low glycemic load diet combined with the national diet and physical activity recommendations.This paper included the first recruited50overweight pregnant women. Placenta tissue and umbilical cord blood sample were collected at delivery and proprely treated according to standard potocal. The methylation of placenta tissue and umbilical cord blood DNA was detected by two-step genome wide methylation based association analysis strategy. Illumina450K whole genome Beadchip was applied for the first stage differential methylation analysis,and Illumina custom designed Goldengate methylation chip was used for the second stage methylation association analysis.Results In this study, their total energy intake in early pregnancy and the second trimester were1633kcal,1679kcal, respectively,accounting for77.8%,73.0%of the energy recommended.The dietary protein intake in early and the second trimester of pregnancy accounted for88.6%,95.0%of the protein recommended.Dietary vitamin A was low,accounting for91.2%,98.6%of the recommended in different times of pregnancy. Dietary vitamin B1was low,accounting for57.4%,57.3%of the recommended in different times of pregnancy. Dietary vitamin B2was low,accounting for58.8%,80.6%of the recommended in different times of pregnancy. Vitamin B3and Vitamin E were basically met the requirement.The intakes of mineral calcium were63.1%AI,81.5%AI in different times of pregnancy.The intakes of iron were111.0%,73.2%in different times of pregnancy.The means of fat intake for treat group showed higher than the control group in in early pregnancy of women.The intake of Vitamin E was significantly different between two groups in second trimester of pregnancy of women.Birth weight of intervention group was heavier than control (3.7±0.5Kg VS.3.5±0.4Kg),but it did not reach statistical significant(P=0.248).The meathylation of2of19CpG sites was significantly difference in umbilical cord blood between two groups,locating in TEKT5and MIR378gene,respecticely. however, there was1of19CpG sites significantly difference in placenta tissue which located in PGBD5.Conclusions These novel data suggest neonatal DNA methylation varies with low glycemic index diet intervention during pregnancy to overweight pregnant women. the potential contribution of these changes to clinically significant postnatal outcomes warrants further investigation.