Intake and blood concentrations of folate and their association with health-related behaviors in Korean college students

Folate food source, usual intake, and folate status in Korean adults

BACKGROUND/OBJECTIVES

The purposes of the study were to investigate folate intakes and plasma folate concentrations as well as estimate folate status in Korean healthy adults.

SUBJECTS/METHODS

A total of 254 healthy 19- to 64-year-old adults (68 men and 186 women) living in Seoul metropolitan area, Gumi, and Kwangju, Korea participated. Three consecutive 24-hour dietary recalls, information on folate supplementation, and fasting blood samples were collected from the subjects.

RESULTS

The mean dietary folate intakes were 587.4 and 499.2 µg dietary folate equivalent (DFE)/day for men and women, respectively. The median dietary intakes of men and women were 566.6 and 474.6 µg DFE/day, respectively. Forty subjects (16.7% of total) less total folate than the estimated average requirement (EAR). Folate intakes of 23.3% of men and 34.8% of women aged 19-29 years did not meet the EAR for folate. Major food sources consumed for dietary folate were baechukimchi (Chinese cabbage kimchi), rice, spinach, eggs, and laver, which provided 44% of dietary folate intake for the subjects. Plasma folate concentrations were 23.4 nmol/L for men and 28.3 nmol/L for women, and this level was significantly lower in men than in women. Approximately 13% of men and 3% of women were folate-deficient, and the percentages of subjects showing folate concentrations lower than 10 nmol/L were 27.9% of men and 6.4% of women.

CONCLUSIONS

Folate intakes of Korean adults in this study were generally adequate. However, one-third of young adults had inadequate folate intakes.

Awareness, knowledge, and use of folic acid among non-pregnant Korean women of childbearing age

BACKGROUND/OBJECTIVES

Folic acid supplementation before pregnancy is known to reduce the risk of neural tube defects. The purposes of this study were to investigate the awareness, knowledge, and use of folic acid supplements along with their associated factors among non-pregnant Korean women of childbearing age.

SUBJECTS/METHODS

From August 2012 to March 2013, 704 women aged 19-45 years completed a self-administered questionnaire regarding their awareness, knowledge, and use of folic acid as well as questions to identify risk of inadequate folate intake.

RESULTS

Approximately 67% of women reported that they had heard of folic acid, and 23.7% had knowledge of both the role of folic acid in preventing birth defects and appropriate time for taking folic acid supplements to prevent birth defects. However, only 9.4% of women took folic acid supplements at the time of the survey. Women aged 19-24 years, unmarried women, and women who had never been pregnant were less likely to be aware and knowledgeable of folic acid or take folic acid supplements. In addition, women at high risk of inadequate folate intake were less likely to take folic acid supplements. In a multivariate analysis, women aged 19-24 years, women with a high school diploma or lower education level, and unmarried women were less likely to be aware and have knowledge of folic acid. The percentage of women taking folic acid supplements was significantly higher among knowledgeable women than among unknowledgeable women.

CONCLUSIONS

These results support our hypothesis that women with knowledge of folic acid are more likely to take folic acid supplements. Therefore, educational programs or campaigns to improve knowledge regarding the importance of folic acid and to promote consumption of folic acid supplements as well as folate-rich foods are needed to target young, less educated, and unmarried women.

Plasma Homocysteine and Serum Folate and Vitamin B12 Levels in Mild Cognitive Impairment and Alzheimer's Disease: A Case-Control Study

Homocysteine (Hcy) is a risk factor for brain atrophy, cognitive impairment, and dementia. Vitamin B₁₂ and folate are cofactors necessary for the methylation of Hcy. However, there is some debate regarding the differing levels of plasma Hcy and serum folate and vitamin B₁₂ among healthy controls, patients with mild cognitive impairment (MCI), and patients with Alzheimer’s disease (AD). This study aimed to evaluate how the levels of plasma Hcy and its biological determinants, folate and vitamin B₁₂, are related to MCI and AD in older Chinese adults. This is a case-control study including 112 subjects with MCI, 89 AD patients and 115 healthy controls. Diagnosis of AD was made according to the NINCDS-ADRDA and MCI with modified Petersen’s criteria. Serum folate and vitamin B₁₂ concentrations were analyzed by radioimmunoassay, and plasma Hcy was assessed by a high-performance liquid chromatography-fluorescence method. Multivariate analysis of regression was used to examine the odds ratio (OR) of MCI or AD with Hcy or vitamin levels. Results have shown that serum folate and vitamin B₁₂ levels were significantly lower, but the plasma Hcy level was higher, in patients with MCI and AD than in healthy controls. Multivariate regression analyses showed that subjects in the lowest folate tertile had significantly higher adjusted ORs for MCI (OR: 3.07; 95% confidence interval [CI]: 1.12, 8.07) and AD (3.42; 95% CI: 1.15, 8.34) compared to subjects in the highest tertile. The highest Hcy tertile was significantly associated with MCI (adjusted OR: 2.81; 95% CI: 1.15, 4.73) and AD (adjusted OR: 3.64; 95% CI: 1.13, 9.04) compared to the lowest tertile. No association existed between low vitamin B₁₂ levels and AD or MCI (p > 0.05). Low blood levels of folate and vitamin B₁₂ and elevated Hcy levels were associated with MCI and AD in older Chinese adults, and the association was stronger for AD.

Preconceptional use of folic acid and knowledge about folic acid among low-income pregnant women in Korea

BACKGROUND/OBJECTIVES

Folic acid supplementation before pregnancy is known to significantly reduce the risk of having a baby with neural tube defects (NTDs). Therefore, it is important for women to be aware of the effects of folic acid supplementation before pregnancy. The purpose of this study was to investigate the awareness and preconceptional use of folic acid and to assess the current knowledge about folic acid among low-income pregnant women in Korea.

SUBJECTS/METHODS

A questionnaire survey was conducted in 2012. Five hundred pregnant women were selected from the waiting list for the Nutriplus program implemented in public health centers using a multistage clustered probability sampling design. Data from 439 women were analyzed after excluding ones with incomplete answers.

RESULTS

Among women who responded to the questionnaire, 65.6% had heard of folic acid before pregnancy, and 26.4% reported on the preconceptional use of folic acid. Women with a university degree or higher education were more likely to be aware of folic acid and to take folic acid in the preconception period. In a multivariate logistic regression, when age, education level, household income, employment status, gravidity, parity, and folic acid awareness were included in the model, folic acid awareness was a strong predictor of preconceptional folic acid use. As of interview, 85.4% and 77.7% of women were aware of the NTD-preventive role of folic acid and the appropriate time to take folic acid, respectively. The main sources of information on folic acid were healthcare professionals (41.2%), friends and family members (31.2%), and the media (26.5%).

CONCLUSIONS

Our results suggest that public health strategies are needed to increase the preconceptional use of folic acid among Korean women.

Assessing the association between natural food folate intake and blood folate concentrations: a systematic review and Bayesian meta-analysis of trials and observational studies

Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy females. A systematic literature review identified studies (1 1992-3 2014) with both natural food folate intake alone and blood folate concentration among females aged 12-49 years. Bayesian methods were used to estimate regression model parameters describing the association between natural food folate intake and subsequent blood folate concentration. Seven controlled trials and 29 observational studies met the inclusion criteria. For the six studies using microbiologic assay (MA) included in the meta-analysis, we estimate that a 6% (95% Credible Interval (CrI): 4%, 9%) increase in red blood cell (RBC) folate concentration and a 7% (95% CrI: 1%, 12%) increase in serum/plasma folate concentration can occur for every 10% increase in natural food folate intake. Using modeled results, we estimate that a natural food folate intake of ≥ 450 μg dietary folate equivalents (DFE)/day could achieve the lower bound of an RBC folate concentration (~ 1050 nmol/L) associated with the lowest risk of a neural tube defect. Natural food folate intake affects blood folate concentration and adequate intakes could help women achieve a RBC folate concentration associated with a risk of 6 neural tube defects/10,000 live births.