Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003–2006

Yang, Quanhe; Cogswell, Mary E.; Hamner, Heather C.; Carriquiry, Alicia L.; Bailey, Lynn B.; Pfeiffer, Christine M.; Berry, R. J.

doi:10.3945/ajcn.2009.28401

Cited by 143 publications

(132 citation statements)

References 17 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…Third, Japanese dietary folate intake may be more difficult to estimate than intake in other countries (40). This is probably because folate is derived mainly from fortified foods or supplements in other countries (24,26) and the variety of folate sources in such countries may be relatively limited compared to the variety in Japan. Fourth, the number of subjects with the TT genotype and higher plasma tHcy levels in our study was relatively small to examine the associations in such groups.…”

Section: Discussionmentioning

confidence: 89%

“…In contrast, the mean and standard deviation (SD) of folate intake was 772611 mg dietary folate equivalents (DFE)/d, including only 19962 mg DFE/d from natural sources among the American population from 2003 to 2006 (24). In several countries including the United States, fortified foods or folic acid supplements are important sources of folate (24)(25)(26), and supplemented folate is more ther-mostable than folate from natural foods (27). The role of the MTHFR polymorphism in folate metabolism may be different in areas where folate intake is relatively low.…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

Fukuda

Hamajima

Wakai

et al. 2014

J Nutr Sci Vitaminol

View full text Add to dashboard Cite

l-5-Methyl-tetrahydrofolate (THF), derived from dietary folate, is involved in the conversion of homocysteine into methionine ( Fig. 1; 1-3). Folate deficiency increases total homocysteine (tHcy) levels (4). Hyperhomocysteinemia is one of the risk factors of cardiovascular disease (4,5) and neural tube defects (NTDs) (6). Maintaining adequate blood folate levels and controlling tHcy levels are important in preventing these diseases.In the folate metabolic pathway, 5,10-methylene-THF is converted into 5-methyl-THF by the enzyme 10-methylene-THF reductase (MTHFR). In the MTHFR C677T polymorphism (rs 1801133), the T allele reduces thermostability of the enzyme and lowers its activity, which were found to be decreased by 30% in heterozygotes and by 65% in homozygotes of minor alleles compared with the CC genotype in an in vitro study (7). However, folate intake could increase blood folate levels even among those with the TT genotype. In previous observational studies, decreased tHcy levels were related to increased blood folate levels (8-11), and increased folate intake was associated with increased blood folate levels (8, 12) and decreased tHcy levels (8,13,14) in each of the MTHFR genotype. These correlations were substantially stronger among those with TT (8,9,[11][12][13][14][15] and those consuming relatively lower amounts of folate (8,12,13). In previous interventional studies using folate supplements or fortified foods, increased folate intake raised blood folate (16-21) and reduced tHcy levels (17-21).However, one study in Japan found no association of serum folate with energy-adjusted folate intake among those with the TT genotype (22). This may be partly explained by the difference in the amount of folate intake and sources of folate. The mean folate intake among Japanese aged 20 y or more was 329 mg/d for men and 189 mg/d for women and the mean intake from supplements or fortified foods among the population was only 1 mg/d in 2008 (23 (Received November 12, 2013) Summary In those with the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype, enzyme activity is lowered. Therefore, these individuals might require an increased intake of folate to maintain or control blood levels of plasma folate or total homocysteine (tHcy). We examined associations of dietary folate intake with fasting plasma folate and total homocysteine (tHcy) according to genotype among 554 Japanese (207 men and 347 women aged 39-89 y) recruited in 2009. Intake of folate was estimated with a food frequency questionnaire. The MTHFR polymorphism was genotyped by a polymerase chain reaction with confronting two-pair primers. The log-transformed concentration of folate or tHcy was regressed on energy-adjusted folate intake in a linear regression analysis. Higher folate intake was associated with higher plasma folate among those with the CC (b50.165, p50.066) or CT (b50.248, p,0.001) genotypes, and with lower tHcy levels only among those with the CC (b520.141, p50.013) genotype. Plasma folate was significantly and inversely associat...

show abstract

Section: Discussionmentioning

confidence: 89%

mentioning

confidence: 99%

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

Fukuda

Hamajima

Wakai

et al. 2014

J Nutr Sci Vitaminol

View full text Add to dashboard Cite

show abstract

“…In 2010, an expert roundtable advised CDC on folate biomarkers and methods for future NHANES surveys [1]. Because in the era of post-fortification, public health concerns are no longer limited to low folic acid intakes, but extend to the safety of high intakes, which are largely driven by supplement use [2], the roundtable advised NHANES to use a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in 2011-2012 [1]. This allows for the measurement of individual folate vitamers, including unmetabolized folic acid (FA), and calculation of tFOL by summation of the individual vitamers.…”

Section: Introductionmentioning

confidence: 99%

A high-throughput LC-MS/MS method suitable for population biomonitoring measures five serum folate vitamers and one oxidation product

et al. 2013

View full text Add to dashboard Cite

Small specimen volume and high sample throughput are key features needed for routine methods used for population biomonitoring. We modified our routine 8-probe solid phase extraction (SPE) LC-MS/MS method for the measurement of five folate vitamers (5-methyltetrahydrofolate , folic acid [FA], plus three minor forms: THF, 5-formylTHF, 5,10-methenylTHF) and one oxidation product of 5-methylTHF (MeFox) to require less serum volume (150 μL instead of 275 μL) by using 96-well SPE plates with 50-mg instead of 100-mg phenyl sorbent and to provide faster throughput by using a 96-probe SPE system. Total imprecision (10 days, 2 replicates/day) for three serum quality control (QC) pools was 2.8-3.6% for 5-methylTHF (19.5-51.1 nmol/L), 6.6-8.7% for FA (0.72-11.4 nmol/L), and ≤11.4% for the minor folate forms (<1-5 nmol/L). Mean (±SE) recovery of folates spiked into serum (3 days, 4 levels, 2 replicates/level) was: 5-methylTHF, 99.4±3.6%; FA, 100±1.8%; minor folates, 91.7-108%); SPE extraction efficiencies were ≥85% except for THF (78%). Limits of detection were ≤0.3 nmol/L. The new method correlated well with our routine method (n=150; r=0.99 for 5-methylTHF, FA, and total folate [tFOL, sum of folate forms]) and produced slightly higher tFOL (5.6%) and 5-methylTHF (7.3%) concentrations, likely due to the faster 96-probe SPE process (1 vs. 5 h) resulting in improved SPE efficiency and recovery compared to the 8-probe SPE method. With this improved LC-MS/MS method, 96 samples can be processed in ~2 h and all relevant folate forms can be accurately measured using a small serum volume.

show abstract

“…In some cases, such as in Ireland and in the UK, the introduction of mandatory folic acid fortification of bread has been advocated (SACN, 2005) and, despite the rising concerns about potential adverse health effects of high folic acid intake levels (Smith et al, 2008;BBC News, 2009, October 20)(see section 2.3.1), implemented. These concerns were also heard in the United States (CDC, 2010) when a recently published study concluded that 2.7% of the adults exceeded the tolerable upper level (UL) of 1 000 µg folic acid per day (Yang et al, 2010).…”

Section: Folic Acid Food Fortification Programsmentioning

confidence: 99%

“…Building upon their review of the dual effects of folic acid intake, Smith et al (2008, p. 517) authorities develop the right strategies for the population as a whole". However, exceedingly high levels of folic acid seem to be more attributable to folic acid supplementation rather than to fortification (Yang et al, 2010).…”

Section: Micronutrient Malnutritionmentioning

confidence: 99%

Market Potential of Folate Biofortified Rice in China

Steur

Gellynck

Blancquaert

et al. 2013

Handbook of Food Fortification and Health

View full text Add to dashboard Cite

Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003–2006

Abstract: At current fortification levels, US adults who do not consume supplements or who consume an average of < or =400 microg folic acid/d from supplements are unlikely to exceed the UL in intake for folic acid.

Cited by 143 publications

References 17 publications

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

A high-throughput LC-MS/MS method suitable for population biomonitoring measures five serum folate vitamers and one oxidation product

Market Potential of Folate Biofortified Rice in China

Contact Info

Product

Resources

About