• Korean Journal of Community Nutrition
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• v.4 no.4
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• pp.512-520
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• 1999

Microbiological method using a 96-well microplate reader for folate assay was established, and folate intake and blood folate concentrations of 23 female college students were assessed. To evaluate folate intake, dietary data were collected by a 3-day weight food record, and serum and RBC folate concentrations were measured by the new method. The coefficient of variation for the new method was less than 10%. Mean daily folate intake of the subjects was 126.7${\mu}g$ which is only 50.7% of the RDA. The mean concentrations of serum and RBC folate were 7.46ng/ml and 294.4ng/ml, respectively, which were within the normal range. These results indicate that folate intake seems to be underestimated due to incomplete food composition database. Therefore, folate database should be appropriately in order to asses folate intake accurately.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.846-855
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• 2009

This study was performed to assess gender differences in rates of obesity, dietary behaviors, and nutrient intakes among college students living in Gwangju. Anthropometric measurements showed that the body mass indexes (BMIs) of the males and females were $22.1{\pm}2.6$ and $20.1{\pm}2.4$ respectively. All obesity indices including BMI, relative body weight (RBW), % body fat by bioelectrical impedence analysis (BIA), and waist-hip ratio (WHR) were significantly higher in the males than in the females. Abdominal fat was also found to be higher in the males whereas underweight was prominent in the female students. The dietary behaviors of the males as determined by dietary scores, were poorer than those of the females. Twenty-four hour dietary recalls revealed that most nutrient intakes were adequate, exceptions of vitamin C, Ca, and folate intakes in both sexes and Fe intake in the female students. Ca and folate intakes were below 75% of the KDRI for both genders. In addition, Unbalanced energy ratios of carbohydrate, protein, and fat were noted in both genders. Effective nutrition education programs targeting college students should be developed and implemented to increase Ca and folate consumption. It is suggested that gender-based nutrition education approaches be created due to poor dietary behavior in males and inadequate nutrient intakes in female college students.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.983-992
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• 1997

During pregnancy and lactation, folate status is important because folate requirements increase during the periods as well as maternal folate status influences on pregnancy outcome and human milk folate; especially folate deficiency around periconceptional period may induce neural tube defects(NTDs) of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy of fetus. There have been a plenty of evidences that maternal folate status deteriorates during pregnancy and lactation if folate needed is not sufficiently provided. The Public health Service of the United States recommends all child-bearing is not sufficiently provided. The Public Health Service of the United States recommends all child-bearing women to intake 0.4mg of folate daily, and the Food and Drug Administration the folate status of child-bearing women and to reduce the rate of occurrence of NTDs. Many authors have insisted that the current recommended dietary allowances of folate for Americans are too low to maintain good folate status. There are little data about Korean folate status including pregant and lactating women. A couple of reports indicated that the folate intakes of Korean pregant and lactating women are below the Korean RDAs of folate and serum folate levels of them are subnormal. The authors pregnant and lactating women. Therefore, it is worth to review the assessment methods of folate status of pregnant and lactating women, folate RDAs for them, the relationships between maternal folate status and pregnancy outcome as well as human milk folate, the methods to increase folate intake, and the problems of large dose of folic acid supplementatiion.

• Journal of Nutrition and Health
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• v.34 no.7
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• pp.797-808
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• 2001

To determine folate intake and food sources in Korea college students, dietary survey was conducted in March, 1999. Dietary data were collected by trained interviewers using the method of 24-hour recalls for 3 consecutive days. The data of 44 male and 62 female students were analyzed with two different nutrient databases in Recommended Dietary Allowances for Korean on the 6th and 7th revisions, and the results were compared. The intakes of energy and nutrients except vitamin A and folate were lower when analyzed with the 7th database than the 6th database. Mean daily folate intakes with the 6th and 7th databases were 172.9$\mu\textrm{g}$, 221.6$\mu\textrm{g}$ for male students while 125.1$\mu\textrm{g}$, 168.0$\mu\textrm{g}$ for female students, respectively. The results showed significantly higher estimates of folate intake with the 7th database, and significantly higher intake in males than females analyzed with both the 6th and 7th databases. Daily folate intake per 1,000kcal (folate density) was 71.1$\mu\textrm{g}$/1000kcal for males and 67.6$\mu\textrm{g}$/1000kcal for females with the 6th database, and 97.9$\mu\textrm{g}$/1000kcal for males and 95.5$\mu\textrm{g}$/1000kcal for females with the 7th database. The differences in folate density between the two databases were signficant, but the differences between the gender were not significant. The proportions of the subjects who consumed more than the RDA of 250$\mu\textrm{g}$ with the 6th and 7th databases were only 4.6%, 29.6% of males and 1.6%, 9.7% of females, respectively. The biggest food source of folate was Kimchi, contributing 17.9% for male and 13.7% for female students with 7th database. Laver, spinach, Ramyon, rice, and Ko Chu Jang together with Kimchi contributed 41.9% for male and 32.4% for females students with the 7th database. These results imply that folate intake reported in the reported inthe previous studies using the 6th database was underestimated. However, the 7th database seems to be still incomplete since 20.5% of 2,932 foods in the database were derived from the other sources, and the rest were imputed from similar foods. Therefore, in order to accurately estimate folate intake of Koreans, folate contents in major contributing foods need to be measured using an appropriate assay method.

• Journal of Nutrition and Health
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• v.55 no.3
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• pp.330-347
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• 2022

Folate, a water-soluble vitamin, acts as a coenzyme for one-carbon metabolism in nucleic acid synthesis and amino acid metabolism. Adequate folate nutritional status during the periconceptional period is known to prevent neural tube defects. In addition, insufficient folate intake is associated with various conditions, such as anemia, hyperhomocysteinemia, cardiovascular disease, cancer, cognitive impairment, and depression. This review discusses the rationale for the revision of the 2020 Korean dietary reference intakes for folate, and suggestions for future revisions. Based on the changes in the standard body weight in 2020, the adequate intake (AI) for infants (5-11 months) and the estimated average requirements (EARs) for 15-18 years of age were revised, but there were no changes in the recommended nutrient intakes (RNIs) and tolerable upper intake levels (ULs) for all age groups. Mean folate intake did not reach RNI in most age groups and was particularly low in women aged 15-29 years, according to the results of the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). The percentages of folate intake to RNI were lower than 60% in pregnant and lactating women, but serum folate concentrations were higher than those in other age groups, presumably due to the use of supplements. Therefore, total folate intake, from both food and supplements, should be evaluated. In addition, the database of folate in raw, cooked, and fortified foods should be further expanded to accurately assess the folate intake of Koreans. Determination of the concentrations of erythrocyte folate and plasma homocysteine as well as serum folate is recommended, and quality control of the analysis is critical.

• Journal of Community Nutrition
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• v.6 no.2
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• pp.91-96
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• 2004

The purpose of this study was to evaluate the folate nutritional status of Korean pregnant women and to investigate the relation between folate levels of maternal-umbilical cord blood, placenta tissue, and pregnancy outcomes. The study subjects consisted of 25 pregnant women who have had normal term deliveries. Dietary folate intakes of the pregnants were estimated by semi quantitative frequency questionnaire and the serum and placenta tissue folate level was measured by microbiological analysis. The total folate intakes of the pregnant women was 655.6 ${\mu}$g/d, which was 131.1% of the Korean RDA for pregnants. Maternal serum folate level was 16.18ng/ml, which was significantly lower than that of umbilical cord blood (34.98ng/ml, p<0.05). Mean folate concentration of the placental tissue was 998.0ng/ml, which was the highest compared to maternal and umbilical cord serum level. Umbilical cord serum folate level and placental tissue folate level were highly influenced by maternal serum folate level. The umbilical cord folate levels of the infant group whose birth weight was higher than 3500g were significantly higher than the group whose birth weight was less than 3500g (p<0.05). The placental folate level was significantly higher in maternal group who showed desirable weight gain during pregnancy (11 - 14kg). In conclusion, the birth weigt was related to the umbilical cord folate level and the maternal weight gain was affected by the placental folate level.

• Journal of Nutrition and Health
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• v.32 no.4
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• pp.376-383
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• 1999

The effects of $\beta$-carotene substitutionl for vitamin A and the chronic consumption of ethanol of ethanol on hepatic folate metabolism were studied it rats. The substitution of $\beta$-carotene for vitamin A depressed hepatic 10-formyl-tetreahydrofolate dehydrogenase(10-formyl-tetrahydrofolate : NADP oxidoreductase, E.C. 1.5. 1.6)activity to 65% of controls(p<0.001) and enhanced hepatic 5, 10-methy-lenetetrahydrofolate reductase(E. C. 6.3.3.2)activity by 56% with respect to control levels(p<0.001). Hepatic activity of 10-formyltertrahydrofolate dehydrogenase was depressed to about half that of control levels by ethanol administration to rats(36% ethanol diet, p<0.001). The activity of 5, 10-methyleneterahydrofolate reductase was not changed by ethanol consumption. The increased activity of 5, 10-methyleneterahydrofolate reductase and the decreased activity of 10-formyltetrahydrofolate dehydrogenase appeared to decrease the level of nonmethyl folate conezyme and the rate of one-carbon metabolism. Plasma homocysteine concentrations were significantly higher in rats fed ethanol(p<0.01) o $\beta$-carotene(p<0.001) than in controls, which suggests that increased activity of 5, 10-methylenetetrahydrofolate reductase can depress homocysteine metabolism. We concluded that dietary substitution of $\beta$-carotene for vitamin A or chronic administration of ethanol resulted in changes in the activity of hepatic folate-dependent enzymes, which could affect the distribution of folate derivatives, plasma homocysteine levels and one-carbon metabolism.

• Nutritional Sciences
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• v.7 no.2
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• pp.88-91
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• 2004

New Dietary Reference Intakes (DRIs) forthe United States and Canada have recently been set for both macronutrients and micronutrients, and are likely to be of interest to health professionals in Korea as well. DRIs are now available for nutrients that did not have Recommended Dietary Allowances set in the past (amino acids, n-3 and n-6 fatty acids, total fiber, added sugar, choline, boron, nickel, and vanadium). Furthermore, the units for the DRIs do not always match those traditionally carried on food composition tables (FCTs). FCT developers will also need to consider carrying new variables to allow the calculation of folate intake in $\mu$g of dietary folate equivalents, vitamin E intake as mg of a-tocopherol (not as mg of a-tocopherol equivalents), and vitamin A intake as $\mu$g of retinol activity equivalents (not as $\mu$g of retinol equivalents). Because the new recommendations for upper levels of intake sometimes refer to a specific form or source of a nutrient, nutrients occurring in foods must be separated from added or supplemental forms for vitamin E, niacin, and folate; pharmacological magnesium must be carried as a separate variable; and preformed vitamin A must be separated from vitamin A from carotenoids. For more information on the DRIs, see: www.nap.edu.

• Journal of Nutrition and Health
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• v.41 no.6
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• pp.518-529
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• 2008

Lactating women have an increased need of folate in the breastfeeding period and, as a consequence, may be in risk of folate deficiency. Folate content of breast milk, furthermore, is important for infants to support exponential growth. However, little is known about the folate content of breast milk from Korean lactating women and their folate nutritional status. In this study, therefore, we investigated the folate status of Korean lactating women and the folate content of their breast milk during extended lactation. A total of 10 subjects who delivered full-term infants participated this study voluntarily. Dietary folate intakes were measured and blood and breast milk were collected at 1, 2, 3, and 6 months postpartum. The women who did not take folic acid supplements failed to meet the recommended intake(RI) of folate for lactating women during all the study periods but those who did met the RI. The unsupplemented women showed lower plasma folate concentrations compared to the supplemented women and all the women were in suboptimal folate status determined by plasma folate concentration throughout the study periods. But the supplemented women showed lower prevalence of suboptimal folate status only at 3 or 6 months postpartum. Plasma folate concentrations of both groups decreased with the progression of lactation. Erythrocyte folate concentrations were not different between the two groups, however, that of the unsupplemented reduced further as time progressed. Plasma homocysteine levels were not different between the two groups. Concentrations of erythrocyte folate and plasma homocysteine were not changed throughout the study periods. Folate contents of their breast milk through the study periods were not different between the two groups and it decreased as lactation progressed in both groups. The results of this study suggest that the folate nutritional status of Korean lactating women might be deteriorated with the progression of lactation without folic acid supplements.

• Journal of Nutrition and Health
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• v.32 no.5
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• pp.592-597
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• 1999

The purpose of this study were to determine the folate status of pregnant women living in kwangju, Korea and to assess the relationships between folate status and pregnancy outcome. Eighty-one women took part in the study: 26 in their first trimester of pregnancy, 23 in the second, and 32 in the final trimester. The folate intake data both from their diets and supplementasage was obtained using a 24-hour recall method and by measuring the use of supplements. Folate levels of serum and erythrocytes were determined by a microbiological assay using Lactovacillus casei(ATTC 7469) as the test organism. A series of determinations for pregnancy outcome was conducted, including birth weight, length, Apgar score at 5 min after birth, and gestational period. The dietary folate intake in each trimester was 118$\pm$85, 148$\pm$117, and 137$\pm$69ug/d, respectively. All levels were far below the Korean recommended diet allowances(RDA)for folate. Eighty-four percent of the subjects consumed supplemental folate after the 20th week of pregnancy until delivery. the supplemental folate intakes in the second and third trimester were 651$\pm$142 and 688$\pm$150ug/d, respectively. Therefore, the women who took folate supplements consumed more folate than the RDA. Serum folate levels for each trimester were 9.0$\pm$3.8, 11.4$\pm$6.0, and 16.3$\pm$11.0ng/ml respectively, greadually increasing as the pregnancy progressed; the serum folate level in the third trimester was significantly higher(p<0.05) than that in first trimester. The erythrocyte folate concentrations in each trimester were recorded as 369.8$\pm$108.8, 396.2$\pm$107.5, and 420$\pm$7 162.6ng/ml respectively. There was no significant differences among the erythrocyte folate concentrations unlike the serum folate levels. There was no significant difference among the erythrocyte folate concentrations unlike the serum folate levels. There was no signifcant correlation between trimester to be important in maintaining adequate folate status, however these results imply that the serum and erythrocyte folate levels were adequate to support the growth of the fetus.