In a first-year course called “Attacks and Defenses,” discussions of the microbiome make up part of the 17 immunology lectures.

One lecture covers “what the microbiome is known to do in the health and disease setting, everything from Alzheimer’s to autism to obesity to cancer. It’s a very broad stroke—there aren’t enough lecture hours to get into specific areas,” said Akiko Iwasaki, PhD, the Waldemar Von Zedtwitz Professor of Immunobiology, and Molecular, Cellular, and Developmental Biology, and a Howard Hughes Medical Institute investigator. “There’s so much discovery going on in the microbiome field. I believe it’s going to have to be expanded every year.”

The new medical school curriculum, unveiled in the fall of 2015, anticipated exactly this kind of scientific advance.

“No matter what we define as the content of the curriculum, no matter what we decide to teach at any given point in time, as we are planning and implementing the curriculum, knowledge is continually changing,” said Richard Belitsky, MD, HS ’82, FW ’83, deputy dean for education, the Harold W. Jockers Associate Professor of Medical Education, and associate professor of psychiatry.

With each advance, faculty and administrators gauge the breakthrough’s importance and whether it’s something medical students need to know. For each new finding, faculty must figure out how and who to teach it, and—there are only so many hours in the day—find space in the curriculum. “People who are teaching are always thinking about this,” Belitsky said. “We rely on the expertise of our faculty to determine the key things our students need to know. We ask them to do it not independently of the curriculum, but coordinated with the rest of the curriculum.”

Belitsky jokes that managing this constant pressure on medical education explains the large bottle of Tums on the desk of Michael L. Schwartz, PhD, associate professor of neuroscience and associate dean for curriculum. It falls to Schwartz to work such discoveries into the classroom. This integration happens in two ways, Schwartz said, the first of which involves faculty keeping tabs on what’s happening in the various departments. “Things come in organically by virtue of the fact that our faculty are world leaders in their fields,” Schwartz said, adding that course directors meet monthly, and faculty have an annual retreat for discussions of curriculum.

Then there is also structured process, as occurred with the opioid epidemic. In response to a growing national crisis, a task force was convened to examine what was being done to prepare future doctors. This review included assessing the curriculum, how well the related material was being taught and learned, and whether the curriculum had omitted any critically important information.

The curriculum integrates basic and clinical science across the four-year continuum. Students begin clinical training early in medical school and revisit the basic sciences during clerkships, which requires faculty coordination to avoid unintended repetition and to place new material in a useful context. “We have structures in place to continuously examine this,” Belitsky said, “and it’s a constant balancing act.”

So far there has been no schoolwide effort to introduce the microbiome into the formal curriculum, but it is happening in some courses. Cyrus Kapadia, MD, FW ’78, professor emeritus of internal medicine, is planning to introduce it in a first-year master course on energy and metabolism. First, he wants to find out what students are already learning about the microbiome. Then, he’ll tap into faculty experts. “We have some people at Yale who are known nationally for their work on the microbiome,” he said. “Not to use those people is a crime.” Kapadia hopes to have a plan for the course by December.

Kapadia pointed out that while there is enormous interest in the microbiome today, interest in gut flora among scientists began decades ago. One fascinating study published in 1934 examined the bacterial population at different levels of the intestines of dogs and monkeys. This work was done decades before Watson and Crick’s paper in Nature on the structure of DNA, and with access to only primitive microbiological techniques. It wasn’t until the 1960s that more advanced microbiological methods enabled a quantitative assessment of the microbial flora at different sites in the intestines from duodenum to colon. Studies in the native population and in Peace Corps volunteers in the 1960s at such centers as the Christian Medical College in Vellore, India, further established the link between gut flora and small intestinal mucosal architecture.

The availability of DNA sequencing methods has brought the field to a higher level. “The big thing now,” Kapadia said, “is that we are talking about the role of the microbiome in diseases affecting the mind, its role in diabetes and obesity, and its connections to cardiovascular disease and to cancer.” Just as the medical curriculum is constantly changing, the hope among faculty is that students will appreciate that medicine requires lifelong learning. Kapadia reminds his preclinical students: “Your education won’t stop when you get to the wards!”