A new study published by the Journal of Leukocyte Biology revealed that high doses of vitamin A may affect the immune system by shutting down the immune response. Too much vitamin A opens the door to infections which would otherwise be controlled by the immune system.
“This study helps to explain the mechanisms of anti-inflammatory effects of vitamin A and by doing so opens the door to identifying novel ways to modulate the immune response and restore its function in situations in which it is dysregulated,” said Mihai G. Netea, M.D., Ph.D., a researcher involved in the work from the Department of Internal Medicine at Radboud University Medical Center in Nijmegen, The Netherlands.
The study consisted of stimulating immune cells with vitamin A. The research findings revealed that cellswhen stimulated with various nitogens and antigens produced fewer cytokines (proteins involved in regulating the immune system by warding off microbes). The cells were exposed to a variety of bacteria and microbial structures, which resulted in long-term activation or training of the cells. The immune cells were no longer activated by microbial structures when the same experiments were performed in the presence of vitamin A.
“The interface of nutrition and immunity is an area of considerable importance, especially in an age when dietary supplements and vitamins are quite common,” said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology. “These new findings shed light on an importance balance in vitamin A levels for optimal immunity. These studies have implications for how we think about daily vitamins, but also for the developing world, where improving diet could have dramatic benefits on how the immune system is trained to respond to different infections.”
Rob J. W. Arts, Bastiaan A. Blok, Reinout van Crevel, Leo A. B. Joosten, Peter Aaby, Christine Stabell Benn, and Mihai G. Netea. Vitamin A induces inhibitory histone methylation modifications and down-regulates trained immunity in human monocytes. J. Leukoc. Bio., June 2015 DOI: 10.1189/jlb.6AB0914-416R