Unmetabolized folic acid is associated with TNF-α, IL-1β and IL-12 concentrations in a population exposed to mandatory food fortification with folic acid: a cross-sectional population-based study in Sao Paulo, Brazil

• Published in: European journal of nutrition Vol. 60; no. 2; pp. 1071 - 1079
• Main Authors: Steluti, Josiane, Miranda, Andreia Machado, De Carli, Eduardo, Palchetti, Cecília Zanin, Fisberg, Regina Mara, Marchioni, Dirce Maria Lobo
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2021; Springer Nature B.V
• Subjects: Adult; Brazil; Chemistry; Chemistry and Materials Science; Cross-Sectional Studies; Cytokines; Folic Acid; Food, Fortified; High-performance liquid chromatography; Humans; IL-1β; Inflammation; Interleukin 10; Interleukin 12; Interleukin 6; Interleukin 8; Interleukin-1beta; Nutrition; Original Contribution; Population; Population studies; Population-based studies; Tumor Necrosis Factor-alpha; Tumor necrosis factor-α; Vitamin B; Brazil; Unmetabolized folic acid; Inflammation; Cytokines; Mandatory fortification; Folic acid
• ISSN: 1436-6207; 1436-6215
• DOI: 10.1007/s00394-020-02307-z

Purpose The study assessed associations between inflammatory markers, as cytokines, adhesion molecules and unmetabolized folic acid (UMFA) among a population exposed to mandatory fortification. Methods Data were collected from a cross-sectional population-based survey ( n  = 302) conducted in São Paulo City, Brazil. UMFA was assayed by a modified affinity-HPLC method with electrochemical detection to measure the different forms of the folate in plasma. We used a commercial test kit to analyze cytokines and adhesion molecules. Multiple logistic regressions were applied to investigate the association between inflammatory markers and UMFA. Multiple models were adjusted for sex, age, self-reported skin color, BMI and smoking status. Results The prevalence of detectable UMFA in this population was high (81.2%), with median concentration of 1.67 nmol/L. The odds ratios (95% CIs) for having higher immunological markers levels among individuals in the highest tertile of UMFA were 0.44 (0.24; 0.81) for TNF-α, 0.92 (0.49; 1.75) for CRP, 1.32 (0.70; 2.48) for ICAM, 0.99 (0.54; 1.81) for VCAM, 0.45 (0.25; 0.83) for IL-1β, 0.74 (0.40; 1.38) for IL-6, 1.34 (0.73; 2.44) for IL-8, 0.65 (0.36; 1.18) for IL-10 and 0.49 (0.27; 0.89) for IL-12. Conclusion UMFA concentrations were inversely associated with elevated proinflammatory markers (TNF-α, IL-1β and IL-12). These results signalize a link between folate metabolism and the inflammatory status of adults in an apparently folate-replete population.