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

Analysis of the mediating role of BMI in associations of different folate forms with hepatic steatosis and liver fibrosis in adolescents in the USA: results from the NHANES 2017-2018

Background

Most studies have explored the relationship between serum total folate and nonalcoholic fatty liver disease (NAFLD) in adults, but there has been no study on the relationship between different folate forms and hepatic steatosis or liver stiffness in adolescents.

Objective

To investigate the association of different folate forms with hepatic steatosis or liver stiffness in adolescents, and further explore the intermediary role of BMI in this relationship.

Methods

The cross-sectional study included 549 participants from the 2017-2018 National Health and Nutrition Inspection Survey (NHANES) survey cycle who had complete data. Four folate data (red blood cell folate, serum total folate, 5-methyl-tetrahydrofolate and folic acid) were included in our study. Controlled attenuation parameters (CAP) and liver stiffness came from the results of liver ultrasound transient elastography. We used linear regression to analyze the relationship between different forms of folate and CAP or liver stiffness, and logistic regression to analyze the relationship between different forms of folate and NAFLD or significant fibrosis. We also used restricted cubic splines to analyze the nonlinear relationship between different forms of folate and NAFLD or significant fibrosis. Finally, we used regression-based intermediary analysis to distinguish the direct and BMI-mediated effects of folate on CAP or liver stiffness. All the analyses adjusted the relevant covariates.

Results

The means of CAP and liver hardness in this study were 223.02dB/m and 5.03kPa, respectively. We found that in model 2, there was a negative correlation between serum total folate (β: -18.53; 95%CI: -29.32 to -7.73) or 5-methyltetrahydrofolate (β: -14.13; 95%CI: -28.98 to -7.86) and CAP. However, when the BMI was further adjusted in model 3, this negative correlation no longer existed (serum total folate: β: -8.36; 95%CI: -17.69 to 0.97; 5-methyltetrahydrofolate: β: -8.05; 95%CI: -17.19 to 1.09). Similarly, we found a negative correlation between serum total folate or 5-Methyl-tetrahydrofolate and liver stiffness in model 2. There was no significant correlation between red blood cell folate or folic acid and CAP or liver stiffness in either model 2 or model 3. The nonlinear relationship between different folate forms and NAFLD or significant fibrosis was not significant. It is estimated that 76% of the total association between serum total folate and CAP is mediated by BMI. The mediating proportion of BMI in the total correlation between serum total folate and liver stiffness was 50%. Similarly, we found that BMI significantly mediated the relationship between 5-Methyl-tetrahydrofolate and CAP or liver stiffness, with a mediating ratio of 77% and 49%, respectively.

Conclusion

Our results show that serum total folate or 5-Methyl-tetrahydrofolate are negatively correlated with hepatic steatosis or liver stiffness in adolescents, and BMI plays major mediating role in this relationship. Our findings emphasize the importance of monitoring the concentration of serum folate, not just the serum total folate concentration.

Vitamin B12, Folate, Homocysteine, Inflammatory Mediators (Interleukin-6, Tumor Necrosis Factor-α and C-Reactive Protein) Levels in Adolescents with Anxiety or Depressive Symptoms

Purpose

To evaluate the prevalence of abnormal vitamin B12, folate, total homocysteine (tHcy), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) levels, to analyze the relationship between these parameters and the severity of anxiety or depressive symptoms, and to explore the possible factors associated with abnormal levels of these parameters in adolescents with anxiety or depressive symptoms.

Methods

Adolescent (aged 12-18 years) outpatients with anxiety or depressive symptoms were recruited. The patient health questionnaire-9 and generalized anxiety disorder scale-7 were used to measure the severity of depression and anxiety. Serum vitamin B12, folate, tHcy, IL-6, TNF-α, and CRP levels were determined.

Results

128 subjects were recruited. The prevalence of vitamin B12 and folate deficiency, tHcy, TNF-α, IL-6, and CRP elevation was 8.6%, 10.2%, 25.8%, 14.8%, 21.9%, and 10.2%, respectively, in adolescents with anxiety or depressive symptoms. Lower vitamin B12 levels were correlated with a higher risk of severe anxiety and depressive symptoms. The severity of some symptoms of anxiety or depression were weakly correlated with vitamin B12, folate, tHcy, IL-6, and CRP levels. Vitamin B12, folate, and tHcy levels were not associated with inflammatory mediators. Vitamin B12 deficiency was associated with older age and higher tHcy levels. Folate deficiency was associated with elevated tHcy. Elevated tHcy was associated with lower vitamin B12 and folate levels. IL-6 elevation was associated with elevated CRP and TNF-α. CRP elevation was associated with older age, higher BMI, and current drinking.

Conclusion

Lower vitamin B12 levels were correlated with a higher risk of severe anxiety or depressive symptoms. Weak correlations were observed between the severity of some symptoms of anxiety or depression and vitamin B12, folate, tHcy, IL-6, and CRP levels. Vitamin B12, folate, and tHcy levels were related to each other. IL-6 elevation was associated with elevated CRP and TNF-α. CRP elevation was associated with older age, higher BMI, and current drinking.

Associations of different serum folate forms with indices of nonalcoholic fatty liver disease and advanced fibrosis

OBJECTIVE

We aim to examine the associations of different serum folate forms (total folate, 5-methyltetrahydrofolate [5-mTHF] and unmetabolized folic acid [UMFA]), with the prevalence of nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis.

METHODS

This cross-sectional analysis was conducted in 6610 participants aged ≥ 18 years from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) database. NAFLD was defined as a United States fatty liver index (USFLI) ≥ 30. Advanced fibrosis was defined as a Fibrosis-4 score (FIB-4) > 3.25, a NAFLD Fibrosis Score (NFS) > 0.676, and a Hepamet Fibrosis Score (HFS) ≥ 0.47, respectively.

RESULTS

The prevalence of NAFLD was 34.5%. Overall, serum total folate and 5-mTHF were inversely associated with the prevalence of NAFLD (both P for trend across quartiles <0.001). A similar trend was found for advanced fibrosis based on NFS and HFS (both P for trend across quartiles <0.05). However, a higher concentration of UMFA was significantly related to a higher prevalence of NAFLD (P for trend across quartiles =0.004). A similar relation was found for advanced fibrosis based on NFS (P for trend across quartiles =0.024).

CONCLUSIONS

Higher concentrations of serum total folate and 5-mTHF were associated with a lower prevalence of NAFLD and advanced fibrosis, while a higher concentration of UMFA was related to a higher prevalence of NAFLD.

Novel Insight Into Nutritional Regulation in Enhancement of Immune Status and Mediation of Inflammation Dynamics Integrated Study In Vivo and In Vitro of Teleost Grass Carp (Ctenopharyngodon idella): Administration of Threonine

This study aims to investigate the effects of threonine (Thr) on immunoregulation in vivo and in vitro of teleost grass carp (Ctenopharyngodon idella). Juveniles (9.53 ± 0.02 g) were reared for 8 weeks with respective Thr diet (3.99, 7.70, 10.72, 14.10, 17.96, and 21.66 g/kg) and then challenged with Aeromonas hydrophila for in vivo study. Macrophages isolated from head kidney were treated in vitro for 48 h with L-Thr (0, 0.5, 1.0, 2.0, 4.0, and 8.0 mM) after 6 h of lipopolysaccharide induction. The results showed that, compared with Thr deficiency (3.99 g/kg), the optimal dietary Thr (14.10g/kg) affected the immunocyte activation in the head kidney (HK) and spleen (SP) by downregulating the mRNA expressions of MHC-II and upregulating CD4 (not CD8), and it mediated the innate immune by enhancing the activities of lysozyme (LZ), acid phosphatase content of complement 3 (C3) and C4, increasing the mRNA abundances of hepcidin, liver expressed antimicrobial peptide-2A (LEAP-2A), LEAP-2B, β-defensin1, downregulating tumor necrosis factor α (TNF-α), IL-6, IL-1β, IL-12p35, IL-12p40, IL-17AF1, and IL-17D partly by attenuating RORγ1 transcriptional factor and nuclear factor kappa B p65 (NF-κBp65) signaling cascades [IKKβ/IκBα/NF-κBp65] and upregulating transforming growth factor β1 (TGF-β1), IL-4/13A, -4/13B, IL-10, and IL-22 partly by GATA-3. Besides these, the optimal dietary Thr regulated the adaptive immune by upregulating the mRNAs of immunoglobulin M (IgM) and IgZ (not IgD). Moreover, 2 mM Thr downregulated in vitro the mRNA abundances of colony stimulating factor-1, inducible nitric oxide synthase, mannose receptor 1, matrix metalloproteinase2 (MMP-2), and MMP-9 significantly (P < 0.05), indicating that Thr could attenuate the M1-type macrophages’ activation. Moreover, L-Thr downregulated the mRNA transcripts of TNF-α, IL-6, and IL-1β associated with impairing the SOCS1/STAT1 signaling and upregulated IL-10 and TGF-β1 partly by accentuating the SOCS3/STAT3 pathway. The above-mentioned observations suggested that Thr improved the immune status in the immune organs of fish by enhancing the immune defense and mediating the inflammation process. Finally, based on the immune indices of LZ activity in HK and C3 content in SP, the optimal Thr for immune enhancement in juvenile grass carp (9.53–53.43 g) was determined to be 15.70 g/kg diet (4.85 g/100 g protein) and 14.49 g/kg diet (4.47 g/100 g protein), respectively.