title: Critical evaluation of lowering the recommended dietary intake of folate.
abstract: We evaluated the recommendation of the Austrian, German, and Swiss Societies for Nutrition of lowering dietary folate intake from 400 to 300 μg dietary folate equivalents/d. A dose-response relation exists between folate intake or plasma level and disease risk within the normal range. Improving folate status can prevent between 30% and 75% of neural tube defects. A prepregnancy plasma folate of >18.0 nmol/L (mean 26.1 nmol/L) is associated with low total homocysteine (tHcy) (<10.0 μmol/L) and optimal prevention of birth defects. Because the closure of the neural tube occurs in the first 8 weeks after conception, women with low prepregnancy folate intake cannot achieve maximal risk reduction. The Austrian, German, and Swiss Societies for Nutrition recommend that young women should additionally supplement with 400 μg folic acid at least 4 weeks before conception. This short time window is not sufficient to achieve optimal plasma folate and tHcy levels in the majority of women. Factors affecting the relation between folate intake and blood biomarkers are total folate intake, baseline plasma folate, time available for supplement use, dose and form (folic acid or methyl folate), genetic polymorphisms, physiological and lifestyle factors. Lowering the recommended dietary folate intake may have important public health consequences. Elderly people and young women are at risk for diseases related to folate shortage. Reducing birth defects through supplementation of folic acid remains a poor option, as <20% of young women (i.e., in Germany) supplement with the vitamin. Recommending adequate food folate intake is crucial for reaching the target protective plasma folate levels in the population.
authors: Department of Clinical Chemistry and Laboratory Medicine, University Hospital of the Saarland, D-66421 Homburg, Germany. Electronic address: rima.obeid@uniklinikum-saarland.de.
authors: Rima
authors: R
authors: Obeid
authors: Division of Metabolic and Nutritional Medicine, University of Munich Medical Centre, D-80337 Munich, Germany.
authors: Berthold
authors: B
authors: Koletzko
authors: Department of Nutrition and Food Science, Rheinische Friedrich-Wilhelms University, D-53115 Bonn, Germany.
authors: Klaus
authors: K
authors: Pietrzik
mesh_terms: D000740:Anemia / Q000517:prevention & control; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood*; D005819:Genetic Markers; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008019:Life Style; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics; D009436:Neural Tube Defects / Q000517:prevention & control; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control; D064167:Recommended Dietary Allowances; D016896:Treatment Outcome
chemical_list: D005819:Genetic Markers; D006710:Homocysteine; D005492:Folic Acid; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: Folate intake; Pregnancy; Requirements