credit: getty images  Microbiome Helps Vitamin A Regulate Immune System    The trick to the microbiome’s work with the immune system is vitamin A, say the researchers. The bacteria moderate active vitamin A levels in the intestine, protecting the microbiome from an overactive immune response. That insight may prove important for understanding and treating autoimmune and inflammatory diseases, says Shipra Vaishnava, an assistant professor of molecular microbiology and immunology at Brown University. “A lot of these diseases are attributed to increased immune response or immune activation, but we’ve found a new way that bacteria in our gut can dampen the immune response,” Vaishnava says. “This research could be critical in determining therapies in the case of autoimmune diseases such as Crohn’s disease or other inflammatory bowel diseases, as well as vitamin A deficiency.” The study appears in the journal Immunity.