A Daily Dose of 5 mg Folic Acid for 90 Days Is Associated with Increased Serum Unmetabolized Folic Acid and Reduced Natural Killer Cell Cytotoxicity in Healthy Brazilian Adults.

Background: The effects of high-dose folic acid (FA) supplementation in healthy individuals on blood folate concentrations and immune response are unknown.Objective: The aim of the study was to evaluate the effects of daily consumption of a tablet containing 5 mg FA on serum folate; number and cytotoxicity of natural killer (NK) cells; mRNA expression of dihydrofolate reductase (DHFR), methylenetetrahydrofolate reductase (MTHFR), interferon γ (IFNG), tumor necrosis factor α (TNFA), and interleukin 8 (IL8) genes; and concentrations of serum inflammatory markers.Methods: This prospective clinical trial was conducted in 30 healthy Brazilian adults (15 women), aged 27.7 y (95% CI: 26.4, 29.1 y), with a body mass index (in kg/m2) of 23.1 (95% CI: 22.0, 24.3). Blood was collected at baseline and after 45 and 90 d of the intervention. Serum folate concentrations were measured by microbiological assay and HPLC-tandem mass spectrometry [folate forms, including unmetabolized folic acid (UMFA)]. We used real-time polymerase chain reaction to assess mononuclear leukocyte mRNA expression and flow cytometry to measure the number and cytotoxicity of NK cells.Results: Serum folate concentrations increased by ∼5-fold after the intervention (P < 0.001), and UMFA concentrations increased by 11.9- and 5.9-fold at 45 and 90 d, respectively, when compared with baseline (P < 0.001). UMFA concentrations increased (>1.12 nmol/L) in 29 (96.6%) participants at day 45 and in 26 (86.7%) participants at day 90. We observed significant reductions in the number (P < 0.001) and cytotoxicity (P = 0.003) of NK cells after 45 and 90 d. Compared with baseline, DHFR mRNA expression was higher at 90 d (P = 0.006) and IL8 and TNFA mRNA expressions were higher at 45 and 90 d (P = 0.001 for both).Conclusion: This noncontrolled intervention showed that healthy adults responded to a high-dose FA supplement with increased UMFA concentrations, changes in cytokine mRNA expression, and reduced number and cytotoxicity of NK cells. This trial was registered at www.ensaiosclinicos.gov.br as RBR-2pr7zp.

Serum folate and cytokines in heterozygous ß-thalassemia.

INTRODUCTION: Folate deficiency is commonly reported in ß-thalassemia. Individuals heterozygous for ß-thalassemia may have higher folate requirements than normal individuals. OBJECTIVES: To document the concentration of serum total folate and its forms in ß-thalassemia heterozygote users (ß-TmU) and nonusers (ß-TmN) of 5 mg folic acid/d; to determine whether folic acid (FA) consumption from fortified foods allows beta-Tm patients, who do not take FA supplements, to meet their dietary folate requirements; and to investigate the association between higher serum unmetabolized folic acid (UMFA) and inflammatory cytokine concentrations. METHODS: Serum total folate and forms were measured in 42 ß-Tm (13 ß-TmU and 29 ß-TmN) and 84 healthy controls. The mononuclear leucocyte mRNA expression of relevant genes and their products and hematological profiles were determined. RESULTS: ß-TmU had higher serum total folate, 5-methyltetrahydrofolate, UMFA, and tetrahydrofolate (THF) compared with ß-TmN. The ß-TmN had lower serum total folate and THF than controls. Plasma total homocysteine (tHcy) was lower in ß-TmU compared with both ß-TmN and controls, while ß-TmN had higher tHcy than controls. ß-TmU had higher IL-8 than their controls while ß-TmN had higher IL-6 and IL-8 than their controls. ß-TmU have higher levels of serum total folate, 5- methyltetrahydrofolate, UMFA, and THF than controls. There was no association between UMFA concentrations and cytokine levels. CONCLUSIONS: Mandatory flour fortification with FA in Brazil may be insufficient for ß-TmN, since they have higher tHcy and lower serum total folate than controls. Furthermore, ß-TmN have higher IL-6 levels than ß-TmU. UMFA was not associated with inflammatory cytokine levels.

Daily supplementation with 5 mg of folic acid in Brazilian patients with hereditary spherocytosis.

Patients with hereditary spherocytosis (HS) have increased rates of erythropoiesis and higher folate requirements. In a case-control study of patients with HS, we evaluated the associations between the use of 5 mg folic acid (FA) daily and serum concentrations of folate, unmetabolized folic acid (UMFA), interleukin (IL)-6, IL-8, IL-10, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α); and mRNA expression of dihydrofolate reductase (DHFR), methylene tetrahydrofolate reductase (MTHFR), IL8, IFNG and TNFA genes. Total serum folate and folate forms were measured in 27 patients with HS (21 users [HS-U] and 6 non-users [HS-NU] of supplemental FA) and 54 healthy controls not consuming 5 mg/day supplemental FA. Each patient was matched to two controls based on age, sex and body mass index. The mononuclear leucocyte mRNA expression of relevant genes and their products were determined. Serum folate, UMFA, 5-methyl-tetrahydrofolate (5-methyl-THF) and tetrahydrofolate (THF) concentrations were significantly higher in HS-U compared with matched healthy controls (p<0.001, n=42). HS-NU had lower serum folate concentrations than matched healthy controls (p=0.044, n=12). HS-U and HS-NU presented similar hematological and biochemical markers profiles. No differences were found between HS-U and HS-NU for cytokine serum concentrations and mRNA expression genes. DHFR mRNA expression was higher in HS-U than in HS-NU. The use of high daily doses of FA for treatment of patients with HS may be excessive and is associated with elevated serum UMFA and elevated DHFR mRNA expression. It is not known whether long-term high-dose FA use by patients with HS might have adverse health effects.

Ácido fólico em excesso: efeitos sobre o metabolismo das vitaminas B2 e B6, o catabolismo do triptofano e a resposta imune / Folic acid excess: effects on vitamin B2 and B6 metabolism, tryptophan catabolism and immune response

Introdução: A suplementação com ácido fólico (AF) é recomendada em algumas condições para evitar a deficiência de folato, como para mulheres no período periconcepcional e durante a gestação. Atualmente, existe uma preocupação quanto ao consumo excessivo de AF pela população pelo uso de suplementos com altas doses dessa vitamina. As vitaminas B6 e B2 agem como cofatores no metabolismo de um carbono, e o uso de altas doses de AF pode influenciar o metabolismo de ambas vitaminas e, consequentemente, interferir em metabolismos importantes das quais elas participam, como a via das quinureninas, e no sistema imune. Objetivo: Avaliar os efeitos da intervenção diária com uma alta dose de AF (5 mg) por 90 dias sobre marcadores do estado das vitaminas do complexo B, e as consequências sobre os metabólitos da via das quinureninas e o sistema imune em adultos saudáveis. Material e Métodos: 64 indivíduos saudáveis foram submetidos à intervenção diária com 5 mg de AF por 90 dias. Coletas de sangue foram realizadas antes (baseline) e após 45 e 90 dias de intervenção. As concentrações séricas de folato e vitamina B12 foram avaliadas por métodos microbiológicos. As concentrações séricas das vitaminas B6 (piridoxal 5'-fosfato (PLP), piridoxal (PL) e ácido 4-piridóxico (PA)), B2 (riboflavina e flavina mononucleotídeo (FMN)), B1 (tiamina e tiamina monofosfato (TMP)) e B3 (ácido nicotínico, nicotinamida e N1-metilnicotinamida), bem como de triptofano, quinurenina e metabólitos, foram avaliadas por LC-MS/MS. A proteína C-reativa ultrassensível (PCRus) foi determinada por imunoturbidimetria, e as concentrações séricas de interleucina (IL)-6, IL-8, IL-10, interferon gama (IFN-γ) e fator de necrose tumoral alfa (TNF-α) foram avaliadas por ensaio multiplex. A expressão de RNAm de DHFR (dihidrofolato redutase), MTHFR (metilenotetrahidrofolato redutase), IL8, TNFA e IFNG em leucócitos mononucleares (PBMC) foram avaliadas por PCR em tempo real. O número de células T regulatórias (Treg) (CD3+, CD4+, CD25high, FoxP3+, CD127-) foi avaliado após incubação dos PBMC com PMA e ionomicina ou veículo por 18h, por imunofenotipagem. Resultados: Houve um grande aumento das concentrações de folato sérico após 45 e 90 dias de intervenção com AF. Não houve diferença nas concentrações de vitamina B12 antes e após a intervenção. As concentrações séricas de PLP foram semelhantes antes e após a intervenção, entretanto, um aumento de PL sérico foi observado após 45 e 90 dias, e de PA após 45 dias, quando comparado ao baseline. Riboflavina e FMN foram maiores após 45 e 90 dias em relação ao baseline. A tiamina sérica foi menor após 45 dias, e as concentrações de TMP foram maiores após 90 dias quando comparados aos períodos anteriores. Não houve diferença nas concentrações de vitamina B3 antes e após a intervenção. Dentre os metabólitos da via das quinureninas, apenas o ácido antranílico apresentou aumento após 45 e 90 dias, enquanto o ácido picolínico diminuiu após 90 dias. PCRus, IL-6, IL-8, IL-10, IFN-γ e TNF-α séricos foram semelhantes no baseline e após a intervenção. Um aumento da expressão de RNAm de DHFR e TNFA foi observado após, respectivamente, 90 dias e 45 e 90 dias de intervenção. Após 90 dias de intervenção com AF, foi observada diminuição do número de células Treg após estímulo com PMA e ionomicina. Conclusão: O uso diário de 5 mg de AF foi associado a alterações nas concentrações séricas de marcadores do estado de vitaminas do complexo B e da via das quinureninas, bem como a diminuição do número de células Treg

Introduction: Folic acid (FA) supplementation is recommended in some conditions to avoid folate deficiency, as women during periconceptional period and pregnancy. Currently, there is a concern about the excessive consumption of FA by population by using supplements with high doses of this vitamin. Vitamins B6 and B2 are cofactors of enzymes of one carbon metabolism and, consequently, may disturb key metabolism in which they participate, as kynurenine pathway, and the immune system. Aim: To assess the effects of a daily intervention with high dose of FA (5 mg) for 90 days on biomarkers of complex B vitamins status and its outcomes in kynurenine pathway metabolites and immune system in healthy adults. Material and Methods: 64 healthy individuals were submitted to a daily intervention with 5 mg of FA for 90 days. Blood samples were collected before (baseline) and after 45 and 90 days of intervention. Serum folate and vitamin B12 were assessed by microbiological assays. Serum vitamin B6 (pyridoxal 5'-phosphate (PLP), pyridoxal (PL) and 4-pyridoxic acid (PA)), vitamin B2 (riboflavin and flavin mononucleotide (FMN)), vitamin B1 (thiamin and thiamin monophosphate)) and vitamin B3 (nicotinic acid, nicotinamide and N1-methylnicotinamide), as well as tryptophan, kynurenine and metabolites, were assessed by LC-MS/MS. C-reactive protein (hs-CPR) was assessed by immunoturbidimetry, and serum interleukin (IL)-6, IL-8, IL-10, interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) were assessed by multiplex assay. Mononuclear leukocytes mRNA expression of DHFR (dihydrofolate reductase), MTHFR (methylenetetrahydrofolate reductase), IL8, TNFA and IFNG were assessed by real time PCR. Regulatory T Cell (Treg) number (CD3+, CD4+, CD25high, FoxP3+, CD127-) was determined after mononuclear leukocytes incubation with PMA and ionomycin or vehicle for 18h, by immunophenotyping. Results: A great increase on serum folate was observed after 45 and 90 days of FA intervention. No differences in serum vitamin B12 were observed before and after intervention. Serum PLP was similar before and after intervention, however, an increase in serum PL was observed after 45 and 90 days, and in PA after 45 days, when compared to baseline. Riboflavin and FMN were increased after 45 and 90 days than in baseline. Serum thiamine was decreased after 45 days than in baseline. Serum TMP was increased after 90 days when compared with previous timepoints. No differences in vitamin B3 were observed after and before FA intervention. Among kynurenine pathway metabolites, anthranilic acid was increased after 45 and 90 days, while picolinic acid was decreased after 90 days. hs-CPR, serum IL-6, IL-8, IL-10, IFN-γ and TNF-α were similar at baseline and after intervention. An increase on mRNA expression of DHFR and TNFA was observed after, respectively, 90 days and 45 and 90 days of intervention. After 90 days of FA intervention, it was observed a decrease on Treg cell number after PMA and ionomycin stimulation. Conclusion: Daily use of 5 mg of FA was associated with changes in serum markers of B-complex vitamins status and kynurenine pathway, as well as decreased number of Treg cells