Combined Vitamin B-12 and Balanced Protein-Energy Supplementation Affect Homocysteine Remethylation in the Methionine Cycle in Pregnant South Indian Women of Low Vitamin B-12 Status.

Low-quality dietary protein intake and vitamin B-12 deficiency could interact to decrease methionine transmethylation and remethylation rates during pregnancy and may affect epigenetic modifications of the fetal genome. The objective of this randomized, partially open-labeled intervention trial was to examine the effect of supplemental high-quality protein and vitamin B-12 on third-trimester methionine kinetics in pregnant Indian women with a low vitamin B-12 status. Pregnant women with low serum vitamin B-12 concentrations (<200 pmol/L) were randomly assigned to 1 of 3 groups: the first group received balanced protein-energy supplementation of 500 mL milk/d plus a 10-μg vitamin B-12 tablet/d (M+B-12 group; = 30), the second group received milk (500 mL/d) plus a placebo tablet (M+P group; = 30), and the third group received a placebo tablet alone (P group; = 33).

Unlike pregnant adult women, pregnant adolescent girls cannot maintain glycine flux during late pregnancy because of decreased synthesis from serine.

During pregnancy, glycine and serine become more important because they are the primary suppliers of methyl groups for the synthesis of fetal DNA, and more glycine is required for fetal collagen synthesis as pregnancy progresses. In an earlier study, we reported that glycine flux decreased by 39% from the first to the third trimester in pregnant adolescent girls. As serine is a primary precursor for glycine synthesis, the objective of this study was to measure and compare glycine and serine fluxes and inter-conversions in pregnant adolescent girls and adult women in the first and third trimesters.

Energy and Protein Supplementation Does Not Affect Protein and Amino Acid Kinetics or Pregnancy Outcomes in Underweight Indian Women.

Background: In India, the prevalence of low birth weight is high in women with a low body mass index (BMI), suggesting that underweight women are not capable of providing adequate energy and protein for fetal growth. Furthermore, as pregnancy progresses, there is increased need to provide methyl groups for methylation reactions associated with the synthesis of new proteins and, unlike normal-BMI American women, low-BMI Indian women are unable to increase methionine transmethylation and remethylation rates as pregnancy progresses from trimester 1 to 3. This also negatively influences birth weight.

Adaptation of in vivo amino acid kinetics facilitates increased amino acid availability for fetal growth in adolescent and adult pregnancies alike.

During pregnancy, adult women with a normal BMI synthesise extra amino acids after an overnight fast by increasing body protein breakdown and decreasing amino acid oxidation. It is not known whether adolescent girls can make these adaptations during pregnancy. The present study aimed to measure and compare the protein, glutamine and alanine kinetics of adult women and adolescent girls at early-, mid- and late-pregnancy.