Jonathan Jacobs

Dr. Jacobs is a gastroenterologist and scientist studying the role of intestinal microbes in inflammatory bowel disease (IBD) and other disorders. He graduated magna cum laude with highest honors from Harvard University with an AB in biochemistry. He subsequently received his MD from Harvard Medical School, graduating magna cum laude in a special field. During college and medical school, he trained in an immunology laboratory studying rheumatoid arthritis with funding from the Howard Hughes Medical Institute. He completed a residency in internal medicine at Stanford University then joined UCLA to pursue gastroenterology training in the Specialty Training and Advanced Research program. He was awarded a PhD in Cellular and Molecular Pathology for his research on the IBD microbiome under the mentorship of Jonathan Braun and afterwards joined the UCLA Division of Digestive Diseases faculty. He co-founded the UCLA Microbiome Center in 2015 and now directs the Microbiome Core, which provides a comprehensive suite of microbiome-related services to support microbiome research by the UCLA scientific community. His research has been published in many scientific journals including Gastroenterology, Proceedings of the National Academy of Science, Cellular and Molecular Gastroenterology and Hepatology, Microbiome, Gut Microbes, and Scientific Reports. Ongoing projects in his laboratory employ animal models and multi’omics analysis of patient cohorts to define the role of microbes and their products in IBD, obesity, colon cancer, and other diseases. 


  • PhD, Cellular and Molecular Pathology, University of California, Los Angeles, CA
  • MD, Harvard Medical School, Boston, MA
  • AB, Biochemistry, Harvard University, Cambridge, MA

Areas of Interest

The Jacobs Laboratory studies the role of the intestinal microbiome in the following diseases using a combination of human observational and interventional studies paired with mechanistic animal model experiments. 

1)      Inflammatory bowel disease (IBD) 
          a. Pre-disease microbiome changes in those at risk for IBD 
          b. Prediction of IBD disease course with microbial biomarkers 
          c. The microbiome-gut-brain axis in stress-induced IBD flare 
          d. Characterization of genes that promote IBD by altering the intestinal microbiome 
          e. Effect of air pollution on the intestinal microbiome and IBD risk 

2)      Obesity 
         a. Effect of a high protein diet on the intestinal microbiome of obesity 
         b. Modulation of the gut microbiome in obesity by bariatric surgery 

3)      Colorectal cancer 
         a. Impact of the intestinal microbiome on colon cancer recurrence after surgery and chemotherapy 
         b. Microbial biomarkers for colorectal neoplasia risk in populations undergoing screening 

4)      Parkinson’s disease (PD) 
         a. Association between the gut microbiome and PD 
         b. Effects of pesticide exposure and PD-associated genetic polymorphisms on the PD microbiome 

Selected Publications