Two scientists and experts in the field of gut health and the gut microbiome spoke to students in Baker Theater this spring.

Robert Baldassano, M.D., and Joseph Zackular, Ph.D. were introduced by Marco Sethi ’27, who took the time to remind his classmates about a lesson from biology class. 

Serving as a Health & Awareness Ambassador, Sethi described the difference between prokaryotic and eukaryotic cells, and, especially, how simple prokaryotic microbes in the gut far outnumber the more complicated eukaryotic cells in the human body. 

“Here’s the twist: these smaller cells might actually be running the show!” he said.

Sethi told students that Baldassano is a professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania and a board-certified pediatric gastroenterologist at the Children’s Hospital of Pennsylvania (CHOP). Zackular is an assistant professor at Perelman School of Medicine at the University of Pennsylvania; both he and Baldassano are also co-directors of Center for Microbial Medicine at CHOP.  

The two scientists took the stage and explained that studies have shown that the microbiome plays a role in everything from anxiety to cancer to athletic performance, and experts are working to bring the promising science around it directly to patient care. 

Zackular, for example, cited a study that showed how fecal transplants have shown great promise in the treatment of c-difficile, a sometimes fatal infection that causes severe diarrhea. 

Research is also showing that food really is a kind of medicine, and Zackular pointed to fermented foods and high-fiber foods as powerhouses for the gut.

“The other opportunity is using food,” Zackular said. “You can harness food; that’s what feeds those microbes.

“What you eat really matters,” he said. “The microbiome is something you can build good habits to support.”

Another study, described by Baldassano, showed that elite Boston Marathon runners had a notable increase in a bacterium called Veillonella before and after their races. Veillonella is important because it eats lactic acid, which can build up in muscles and interfere with performance. 

“I think you’ll be hearing more about this in the future,” he said. 

Baldassano also told the boys about his 10 years of medical training and that he has a personal interest in his career choice — he was diagnosed with Crohn’s disease while still in his 20s. It was his mom who first put the notion of finding a cure in his mind — she offered the idea that somebody, somewhere would be working on a remedy.

“I thought, maybe I could be one of those somebodies,” Baldassano said, adding as he looked around Baker Theater: “Everybody in this room could be one of those somebodies.”

Baldassano and Zackular gave a separate evening talk for parents. Their visit served as the second installment of the 2025–26 ’WICK Center Speaker Series, now in its fourth year.