The effects of high maternal folate status on the offspring are unknown; however, early life exposure to environmental stimuli, including dietary factors, is thought to influence the risk of developing chronic disease. An animal study was performed to determine the effect of maternal folic acid supplementation during pregnancy and lactation on DNA methylation and global gene expression patterns in the offspring. Supplementation of the maternal diet with folic acid (5, 8, and 25 mg/kg diet) induced global DNA hypomethylation in the liver of juvenile and adult offspring, and altered the expression of the imprinted H19 gene and genes involved in lipid metabolism, coagulation, and iron transport and homeostasis. Our data suggest that intrauterine and early postnatal periods are susceptible to changes in DNA methylation and gene expression in response to high levels of folic acid, which may be associated with health status and disease later in life.

There are increasing concerns that exposure to unmetabolized folic acid, which results from folic acid intakes that overwhelm the liver’s metabolic capacity, may be associated with adverse effects. In this study, we examined the folic acid status of women of reproductive age in relation to dietary intake and the effect of folic acid supplementation (1.1 mg or 5 mg). Plasma unmetabolized folic acid was not significantly correlated with folate intake estimated by food frequency questionnaire or biomarkers. The proportion of women with detectable levels of unmetabolized folic acid increased from 65% to 100% after twelve weeks of supplementation (p < 0.05), however, the increase in concentrations did not reach statistical significance and the effect was not sustained. Moreover, there were no significant differences between the two doses. This suggests that there are mechanisms by which the body adapts to high folic acid intakes to limit exposure to unmetabolized folic acid.

The effects of high maternal folate status on the offspring are unknown; however, early life exposure to environmental stimuli, including dietary factors, is thought to influence the risk of developing chronic disease. An animal study was performed to determine the effect of maternal folic acid supplementation during pregnancy and lactation on DNA methylation and global gene expression patterns in the offspring. Supplementation of the maternal diet with folic acid (5, 8, and 25 mg/kg diet) induced global DNA hypomethylation in the liver of juvenile and adult offspring, and altered the expression of the imprinted H19 gene and genes involved in lipid metabolism, coagulation, and iron transport and homeostasis. Our data suggest that intrauterine and early postnatal periods are susceptible to changes in DNA methylation and gene expression in response to high levels of folic acid, which may be associated with health status and disease later in life.

Thesis (M.P.H.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 36-39).

No description available.

Human leukemia cell K562 in culture displayed an absolute requirement for folate, proliferating at optimal rate only when the total intracellular folate concentration was greater than 1.5 uM. This critical intracellular concentration was maintained by extracellular 5-formyltetrahydrofolic acid or 5-methyltetrahydrofolic acid at a 100-fold lower concentration than folic acid. Growth rate of folate-deficient cells was proportional to intracellular concentration of fully-reduced, non-methylated folate but not to intracellular 5-methyltetrahydrofolate concentration. Growth of folate-deficient cells was stimulated by inosine but not by thymidine, suggesting that the primary cause of growth restriction in these cells was purine deficiency. Serine stimulated, and glycine inhibited, growth of K562 cells, likely by modulating the supply of one-carbon units for folate metabolism. Folate-deficient cells were larger in size than folate-replete cells, but megaloblastic morhology was not observed. DNA content of folate-deficient cells was predominantly characteristic of cells in S or G2/M phases of the cell cycle.

No description available.

The objective of this study was to determine Thai women's nutrition awareness of folic acid and its role in the prevention of neural tube defects. Three hundred and two Thai women between 18-45 years completed a 30 itemized survey. There was a significant lack of nutrition awareness of folic acid. Many women (n= 274; 91.9%) had not heard of neural tube defects (NTD) and only 8.1 % (n=24) had heard of spina bifida/NTD. More than 50% (n=176) were unaware of NTD. Only 11.6% of the women (n=35) thought consuming vitamins during pregnancy would reduce the risk of birth defects. More than 80% of the women reported the best time to take folic acid supplement was during pregnancy. Less than 20% of the women indicated taking folic acid supplement before or after pregnancy. In this population, nutrition awareness of folic acid was minimal. / Department of Family and Consumer Sciences

Graduation date: 1978

Rice is an important dietary grain but may be difficult to fortify with water-soluble vitamins due to the losses incurred during processing and preparation. Edible coatings can offer reasonable protection against folate processing losses in fortified rice, in particular pectin (Shrestha, 2003). However, pectin, an indigestible fibre, may entrap or bind added folate, decreasing its absorption efficiency. Healthy volunteers (n=26, 18-39 yrs) received oral 400??g [13C5]PteGlu doses in three separate test meals in randomized cross-over trials as follows: 1) aqueous 2) 200g white rice and 3) 200g of pectin-coated rice premix. A plasma AUC0-8 was conducted (0, 1, 2, 5 and 8 hrs postprandial). Subjects followed a low folate basal diet (112??12 ??g/day) - verified using L.casei microbiological assay - during the AUC and for 24 hours prior. Optimisation of the pectin-coated rice premix gave folic acid coating and cooking losses of 33.5% and 15.5% respectively. The mean test dose error per 400??g folic acid was ?? 26 ??g. Single- or tri- enzyme extraction of fortified rice extracts did not significantly increase the mean assayable folate content compared to the mean folic acid content. The levels of plasma [13C5]5-methyl-THF, [13C5]PteGlu and 5-methyl-THF were quantified using a validated HPLC-tandem MS method. The calibration curves indicated good response linearity in the 0-100 ng/mL range (R2&gt0.9978). Inter- and intra-assay variation of 5-methyl-THF (100 ng/mL) was 6.9% (n=6) and 5.2% (n=4) respectively. The mean recovery of 5, 20 and 50 ng/mL 5-methyl-THF in spiked plasma extracts was 98.6 ?? 8.7%, 89.3 ?? 2.8% and 92.6 ?? 3.7% (n=3) respectively. Standard Reference Material-1846, infant formula (129??28 ??g/100g) was measured at 110 ?? 15 ??g folic acid/100g. The relative bioavailability of the folic acid in meals 2 and 3 was measured by comparing their [13C5]5-methyl-THF AUC???s relative to meal 1. The relative bioavailabilities (Mean % ?? CI) of meals 2 and 3 were 86.5 ?? 4.6 % and 68.7 ?? 5.4 % respectively. It appears the pectin coat moderately reduces short-term folic acid bioavailability. These studies define the basis for calculating the amount of folic acid to be added to rice so that an adequate amount can be absorbed after coating and cooking losses. Pectin coatings may be a useful means of increasing the folate status of populations that rely heavily on rice as a staple.