Consumption of selenium-enriched broccoli increases cytokine production in human peripheral blood mononuclear cells stimulated ex vivo, a preliminary human intervention study.

Scope: Selenium (Se) is a micronutrient essential for human health, including immune function. Previous research indicates that Se supplementation may cause a shift from T helper (Th)1- to Th2-type immune responses. We aim to test the potential health promoting effects of Se-enriched broccoli. Methods and results: In a human trial, 18 participants consumed control broccoli daily for 3 days. After a 3-day wash-out period, the participants were provided with Se-enriched broccoli containing 200 mu g of Se per serving for 3 days. Plasma and peripheral blood mononuclear cell (PBMC) samples were collected at the start and end of each broccoli feeding period for analysis of total Se and measurement of cytokine production from PBMC stimulated with antigens ex vivo. Plasma Se content remained consistent throughout the control broccoli feeding period and the baseline of the Se-enriched broccoli period (1.22 mu mol/L) and then significantly increased following 3 days of Se-enriched broccoli feeding. Interleukin (IL-2, IL-4, IL-5, IL-13, and IL-22) production from PBMC significantly increased after 3 days of Se-enriched broccoli feeding compared with baseline. Conclusion: This study indicates that consumption of Se-enriched broccoli may increase immune responses toward a range of immune challenges.