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.
| Autor: | Paniz, Clovis, Felix Bertinato, Juliano, Rodrigues Lucena, Maylla, De Carli, Eduardo, da Silva Amorim, Patrícia Mendonça, Wataru Gomes, Guilherme, Zanin Palchetti, Cecília, Stella Figueiredo, Maria, Pfeiffer, Christine M., Fazili, Zia, Green, Ralph, Guerra-Shinohara, Elvira Maria, Bertinato, Juliano Felix, Lucena, Maylla Rodrigues, Amorim, Patrícia Mendonça da Silva, Gomes, Guilherme Wataru, Palchetti, Cecília Zanin, Figueiredo, Maria Stella |
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| Předmět: |
FOLIC acid
KILLER cells TETRAHYDROFOLATE dehydrogenase METHYLENETETRAHYDROFOLATE reductase INTERFERON gamma TUMOR necrosis factors INTERLEUKIN-8 genetics BODY mass index RNA metabolism CLINICAL trials COMPARATIVE studies DIETARY supplements IMMUNITY INFLAMMATORY mediators INTERLEUKINS LONGITUDINAL method RESEARCH methodology MEDICAL cooperation OXIDOREDUCTASES POLYMERASE chain reaction REFERENCE values RESEARCH RESEARCH funding VITAMIN B complex EVALUATION research NUTRITIONAL status |
| Zdroj: | Journal of Nutrition; Sep2017, Vol. 147 Issue 9, p1677-1685, 9p |
| Abstrakt: | 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. [ABSTRACT FROM AUTHOR] |
| Databáze: | Complementary Index |
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