Abstract
Background and objectives: Immune function typically declines with age, increasing susceptibility to disease. Many factors contribute to this decline, including nutritional status. Emerging evidence shows associations of folate and related B-vitamins (B12, B6, and riboflavin) with immune health, but these interactions are complex. The aim of this study was to investigate B-vitamin biomarkers in relation to immune function in ageing. We hypothesised that the higher status of certain B-vitamins will be associated with improved inflammatory markers. Methods: The data were analysed from the Trinity-Ulster-Department of Agriculture (TUDA) study, aimed at investigating health and lifestyle factors in relation to disease, in community-dwelling older adults recruited from the island of Ireland (2008–2012). Of the 5186 TUDA participants, 2724 fulfilled the inclusion criteria for the current investigation. We measured B-vitamin biomarkers, namely, red blood cell folate, serum B12, plasma pyridoxal-5-phosphate (PLP; B6), the erythrocyte glutathione reductase activation coefficient (EGRac; riboflavin), pro-inflammatory markers (interleukin IL-6, tumor necrosis factor-alpha [TNF-α], and c-reactive protein [CRP]), and the anti-inflammatory marker (IL-10). Results: Plasma PLP was negatively associated with CRP (β: −0.066; 95% CI: −0.005–0.000; p = 0.020), and plasma homocysteine was positively associated with CRP (β: 0.062; 95% CI: 0.003–0.066; p = 0.030) and TNF-α (β: 0.086; 95% CI: 0.023–0.124; p = 0.004). No other significant associations between B-vitamins and inflammatory markers were found. As regards general characteristics, the concentrations of IL-6 (p = 0.040) and CRP (p = 0.010) increased with age; CRP (p < 0.001); TNF-α (p = 0.024) increased with BMI; higher IL-6 (p = 0.041) was associated with living alone; and higher CRP (p < 0.001) was associated with smoking. Discussion: These preliminary findings suggest that improving vitamin B6 status and maintaining a healthy weight in older age may support a healthier immune system. Further investigation, particularly in the form of randomised controlled trials, is required to confirm the current findings and investigate the impact of B-vitamins on immune function.
Author Contributions
Conceptualization, H.M. and L.H.; methodology, U.S.; formal analysis, U.S., A.C. and M.C.; investigation, H.M.; resources, H.M.; data curation, L.H., M.C. and A.C.; writing—original draft preparation, U.S.; writing—review and editing, J.D. and C.H.; supervision, L.H., H.M., C.H. and J.D. project administration and funding acquisition, H.M. All authors have read and agreed to the published version of the manuscript.
Funding
This work was supported by the Vice Chancellor’s Research Scholarship (S.G.), Ulster University.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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