Folate and Vitamin B<sub>12</sub> Metabolism: Overview and Interaction with Riboflavin, Vitamin B<sub>6</sub>, and Polymorphisms

Shane, Barry

doi:10.1177/15648265080292s103

Cited by 125 publications

(138 citation statements)

References 54 publications

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“…1,2 Poor folate status in vulnerable fertile women increases the risk of neural tube birth defects. [3][4][5] As a measure to decrease the risk of this birth defect, folic acid has been added to staple foods such as wheat or maize flour.…”

Section: Introductionmentioning

confidence: 99%

Folate and Vitamin B₁₂Status in Latin America and the Caribbean

et al. 2015

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Background: The current magnitude of folate and vitamin B 12 deficiency in Latin America and the Caribbean is uncertain. Objective: To summarize data on plasma or serum vitamin B 12 and folate concentrations in Latin America and the Caribbean reported since 1990, a period that covers the era before and after the introduction of folic acid fortification. Methods: A systematic review was conducted in 2012 and updated in 2014. Studies and surveys using biochemical biomarkers and conducted in apparently healthy individuals were identified. Results: Folate deficiency in Latin America and the Caribbean appears not to be a public health problem (prevalence < 5%) after the introduction of folic acid fortification. However, there is some indication that high rates of low or marginal vitamin B 12 status remain in most locations and across population groups. Conclusions: Adding vitamin B 12 as a fortificant with folic acid may be the best strategy in areas where vitamin B 12 deficiency is an established concern.

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Section: Introductionmentioning

confidence: 99%

Folate and Vitamin B₁₂Status in Latin America and the Caribbean

et al. 2015

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“…These biomarkers include plasma/serum concentrations of B vitamins (folate, cobalamin, vitamins B2 and B6) (8 ), methylamines (choline, betaine, dimethylglycine) (9 ), metabolites (total homocysteine, methylmalonic acid) reflecting B vitamin status in tissues (10 ), methylarginines linked to endothelial function (11 ), and tryptophan metabolites along the kynurenine pathway (12 ), which depends on both vitamin B6 and B2.…”

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confidence: 99%

Kinetic Modeling of Storage Effects on Biomarkers Related to B Vitamin Status and One-Carbon Metabolism

et al. 2012

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BACKGROUND Biomarkers and metabolites related to B vitamin function and one-carbon metabolism have been studied as predictors of chronic diseases in studies based on samples stored in biobanks. For most biomarkers, stability data are lacking or fragmentary. METHODS Degradation and accumulation kinetics of 32 biomarkers were determined at 23 °C in serum and plasma (EDTA, heparin, and citrate) collected from 16 individuals and stored for up to 8 days. In frozen serum (−25 °C), stability was studied cross-sectionally in 650 archival samples stored for up to 29 years. Concentration vs time curves were fitted to monoexponential, biexponential, linear, and nonlinear models. RESULTS For many biomarkers, stability was highest in EDTA plasma. Storage effects were similar at room temperature and at −25 °C; notable exceptions were methionine, which could be recovered as methionine sulfoxide, and cystathionine, which decreased in frozen samples. Cobalamin, betaine, dimethylglycine, sarcosine, total homocysteine, total cysteine, tryptophan, asymetric and symmetric dimethyl argenine, creatinine, and methylmalonic acid were essentially stable under all conditions. Most B vitamins (folate and vitamins B2 and B6) were unstable; choline increased markedly, and some amino acids also increased, particularly in serum. The kynurenines showed variable stability. For many biomarkers, degradation (folate and flavin mononucleotide) or accumulation (pyridoxal, riboflavin, choline, amino acids) kinetics at room temperature were non–first order. CONCLUSIONS Data on stability and deterioration kinetics for individual biomarkers are required to optimize procedures for handling serum and plasma, and for addressing preanalytical bias in epidemiological and clinical studies.

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“…El almacenamiento de folatos en adultos bien nutridos es de 12-28 mg. Estudios en humanos y animales señalan que el hígado, el tejido conjuntivo, eritrocitos, riñones y tracto gastrointestinal contienen más de 97% del total de folatos del organismo. Aunque existen reservas hepáticas cercanas al 50% del total, en deficiencia estas sólo satisfacen los requerimientos por unos meses 1,7,8 . La cinética del metabolismo de folatos indica que los procesos de captación, síntesis, reciclaje y catabolismo son saturables 9 .…”

Section: Fisiologíaunclassified

“…Los requerimientos diarios de B 12 en personas saludables alcanzan al 0,1% de los depósitos. Los signos de deficiencia aparecen cuando el pool corporal cae bajo 300 μg 1,6,13 .…”

Section: Fisiologíaunclassified