Could bile acids—the fat-dissolving juices churned out by the liver and gallbladder—also play a role in immunity and inflammation?

The answer appears to be yes, according to two separate Harvard Medical School studies published in Nature.

The findings of the two studies, both conducted in mice, show that bile acids promote the differentiation and activity of several types of T cells involved in regulating inflammation and linked to intestinal inflammatory conditions. They also reveal that gut microbes are critical for converting bile acids into immune-signaling molecules.