Read Full Story Back when she was a high school athlete, Michelle Rooks, who graduated with her Ph.D. in biological sciences in public health this month, saw how making changes to her diet could improve her performance. In her research at Harvard T.H. Chan School of Public Health, Rooks has taken her interest in the connection between food, nutrition, and health to the microscopic level—she’s been working to understand the biological mechanisms that can cause bacteria in the gut to initiate and drive disease.Cracking the code of this bacterial community—known as the gut microbiome—may ultimately lead to new treatments for diseases like inflammatory bowel disease (IBD) and colorectal cancer, as well as interventions to help keep those at risk for those diseases from getting sick.While the community of bacteria we carry in our gut is unique to each individual, researchers are beginning to identify the bacterial signatures of disease. Using preclinical mouse models of IBD, Rooks has pinpointed differences between gut microbiomes in remission and those with active disease. She has also studied the mechanisms that enable one particular family of bacteria to grow and exacerbate disease when its host is experiencing stress—a potentially important marker of IBD.Creating a picture of what’s “normal” and what isn’t in the gut microbiome could help physicians someday treat painful flare-ups of IBD before they occur. If a patient showed signs of certain bacterial changes a treatment could be administered to restore their gut to a healthier state.