A daily dose of 5 mg of folic acid for 90 days is associated with increased serum unmetabolized folic acid and reduced natural killer cell cytotoxicity in healthy Brazilian adults
| Autor: | Zia Fazili, Maylla Rodrigues Lucena, Ralph Green, Clóvis Paniz, Eduardo De Carli, Juliano Felix Bertinato, Maria Stella Figueiredo, Cecília Zanin Palchetti, Guilherme Wataru Gomes, Patrícia Mendonça da Silva Amorim, Christine M. Pfeiffer, Elvira Maria Guerra-Shinohara |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Adult Male medicine.medical_specialty medicine.medical_treatment Medicine (miscellaneous) Nutritional Status Real-Time Polymerase Chain Reaction Article 03 medical and health sciences Immune system Folic Acid Reference Values Internal medicine Dihydrofolate reductase medicine Humans Interleukin 8 Prospective Studies RNA Messenger Cytotoxicity Methylenetetrahydrofolate Reductase (NADPH2) 030109 nutrition & dietetics Nutrition and Dietetics biology business.industry Tumor Necrosis Factor-alpha Interleukin-8 Immunity Killer Cells Natural Tetrahydrofolate Dehydrogenase 030104 developmental biology Real-time polymerase chain reaction Endocrinology Cytokine Methylenetetrahydrofolate reductase Immunology Dietary Supplements Vitamin B Complex biology.protein Tumor necrosis factor alpha Female Inflammation Mediators business Brazil |
| Popis: | 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 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. |
| Databáze: | OpenAIRE |
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