Scientific Publications
Selenium supplementation has beneficial and detrimental effects on immunity to influenza vaccine in older adults
Clinical Nutrition, 1-9
Although selenium (Se2) is important for a well-functioning immune system there is no evidence that Se-supplementation enhances immune responses to influenza (flu2) virus. Objective: A randomized trial was designed to determine the effects of Se-supplementation on a variety of parameters of anti-flu immunity in healthy aging subjects (50-64 years). Methods: Using a double-blind design, a 12-week dietary intervention was undertaken in six groups of individuals with plasma Se levels n=20), 50 µg Se/d (SeY-50/d; n=18), 100 µg Se/d (SeY-100/d; n=21) or 200 µg Se/d (SeY-200/d; n=23). Two groups were given onion-containing meals with either n=17) or 50 µg Se/d (SeO-50/d; n=18). Flu vaccine was administrated at week 10 and immune parameters were assessed until week 12. Results: Supplementation with SeY and SeO affected different aspects of cellular immunity. SeY increased Tctx-ADCC cell counts in blood (214%) before flu vaccination and T cell proliferation in a dose-dependent manner (500%), IL-8 (169%) and IL-10 (317%) secretion after in vivo flu challenge. Positive effects were contrasted by reduction in the granzyme B content of CD8 cells (55%). SeO also enhanced T cell proliferation after vaccination (650%), IFN-g secretion (289%), granzyme (209%) and perforin (190%) content of CD8 cells but inhibited TNF-α synthesis (42%). Onion on its own had an adverse effect on the number of NKT cells in blood (38%). Mucosal flu-specific antibody responses were unaffected by Se-supplementation. Conclusion: Se-supplementation in healthy human adults with marginal Se status resulted in both beneficial and detrimental effects on cellular immunity to flu that was affected by the form of Se, supplemental dose and delivery matrix. These observations call for a thorough evaluation of the risks and benefits associated with Se-supplementation.
Clinical Nutrition, 1-9
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