During the 2024-25 Colgate women’s hockey regular season, four members of the team embarked on a study that examined the relationship between the gut microbiome and non-concussive head impacts in women’s hockey players.

Using sensors on helmets, the student-athletes recorded head impacts that occurred during games and practices of eight Raiders who participated in the study.

In addition, participants filled out health and diet surveys, and provided regular stool samples, which contain DNA that allows the researchers to analyze the gut microbiome, which is a community of trillions of microorganisms lining the intestinal tract. 

The gut microbiome plays an important role in many functions of the body. Research has suggested that the gut microbiome undergoes changes after a collision to the head.

A previous study involving Colgate Football a few years ago showed that the gut microbiome undergoes changes after a collision to the head. But none of these studies have focused on female athletes.

Gwen Eichfeld ’25, the study’s lead student researcher and a neuroscience major, began the study after Ken Belanger, the Russell Colgate Distinguished University Professor of Biology, pitched the idea.

“This study is one of the first to focus on female athletes, who are underrepresented in this area of research yet often experience more severe and longer-lasting symptoms than their male counterparts,” said Eichfeld, who played four seasons on defense for the Raiders before graduating in May.

Joining Eichfeld for the project were teammates Elyssa Biederman ’26, Avery Pickering ’27, and Sara Stewart ’26, who are all studying either biology or molecular biology. All four student-athletes completed the work as part of an Independent Study course last spring.

The goal of the study was to understand if non-concussive head impacts cause changes in the gut microbiome. Throughout the study, the researchers will observe microbiome changes immediately after an impact to the head and throughout the season as head impacts accumulate, Eichfeld said.

“Recent research has shown that the gut microbiome and the brain are closely linked, and interact with each other during inflammatory responses,” Eichfeld said. “However, the specific details of the gut-brain connection remain unknown. Thus, we were curious about how the gut responds to head impacts.”

Body checks are prohibited in women’s collegiate hockey, but it’s still a physical — and fast — sport where head injuries occur each season, including concussions. The NCAA is reviewing body contact in the sport and whether it should mirror the Professional Women’s Hockey League, where the game is more physical than on the collegiate level. 

“In the bigger picture, this study can help us understand the link between the gut and the brain, which is becoming increasingly relevant for both the causes and treatments of many neurological disorders,” Eichfeld said.

A sensor is pictured on the back of Elyssa Biederman's helmet during the 2024-25 season.

The data-collection portion of the study is complete. Now the researchers are preparing the gut microbiome DNA for genetic sequencing, which will reveal data on gut microbiome changes, Eichfeld said. 

“Once we have the sequencing results we will be able to compare the head impact data with gut microbiome sequence data to determine how the microbiome responds to head impacts ,” Eichfeld said.

Eichfeld has graduated and plans to spend two years involved in research or seeking work in neuroscience before beginning medical or graduate school, starting with a prestigious year-long Watson Fellowship. But the study will continue under the direction of Biederman, Pickering, and Stewart. Other members of the team might also join the project.

Belanger said the group hopes to publish its work in a scientific journal in the coming year.

Eichfeld worked with Belanger on proposals for approval of the study by Colgate’s Institutional Review Board. They also applied for funding from the University’s Mind, Brain, and Behavior Initiative.

The research team obtained the sensors from a Swiss company called Bearmind, which developed a head-impact detection system specifically for ice hockey.

“Gwen has been an outstanding mentor to these students,” Belanger said. “And Sara, Elyssa, and Avery have all stepped right in and become outstanding partners and each have taken on leadership roles in their own way in this collaborative work.”

In addition, Belanger applauded women’s hockey head coach Stefan Decosse and Steve Chouinard, the senior associate athletics director for health and performance, for their support. He also stressed that the project would not have been possible without funding from Colgate’s Mind, Brain, and Behavior Initiative.

Decosse said he was thrilled when Eichfeld approached him about launching the study.

“I love this,” Decosse said. “This is what we are all about. We are so privileged to have incredibly well-rounded student-athletes who are devoted to their craft on the ice. But they come to Colgate because they also have interests that lie outside the athletic world, too.”