A new study revealed that intake of Vitamin A above the normal level will shut down the body’s trained immunity and opens door to infections. The findings suggest that supplementation of the vitamin above and beyond normal levels may have negative health consequences although it has many health benefits.
“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 dis-regulated,” said one of the researchers Mihai Netea from the Radboud University Medical Center in Nijmegen, The Netherlands.
To find this fact, Netea and colleagues stimulated immune cells that are isolated from volunteers with Vitamin A. They found that cells produced only fewer cytokines that help ward off microbes upon stimulation with various mitogens and antigens. In addition, the cells were also stimulated with various microbial structures, which resulted in long-term activation or training of the cells.
When the same experiments were performed in the presence of vitamin A, the researchers observed that microbial structures were no longer able to activate the immune cells.
The study was published in the Journal of Leukocyte Biology.