Signs of a concussion can be found in the gut, according to a Houston Methodist study. Researchers who conducted the study took blood, stool, and saliva samples from 33 Rice University football players and found that tracking changes in the gut microbiome following head injury could act as an important marker for diagnosing concussions and assessing when it’s safe for players to return to the game.
Diagnosing concussions is currently based solely on self-reported symptoms such as dizziness, headache, nausea, etc. Injury to nerve cells is difficult to detect because it occurs on a microscopic level that can’t be detected on imaging scans. While there are blood protein biomarkers linked to traumatic brain injury, the increases in blood concentration are so minimal that developing a commercial test sensitive enough to detect the increase is very challenging.
The study found that two abundant bacterial species in the stool of healthy people plummet following a head injury. Researchers also found a correlation between brain injury proteins in the blood and brain injury bacteria in the stool.
Because the central nervous system (located in the brain) and the enteric nervous system (located in the gut) are so closely linked, head trauma results in immediate changes in the gut. Brain injury leads to inflammation which triggers proteins and other molecules to circulate in the bloodstream and pass through the intestinal barrier, generating gut alterations. Scientists believe full recovery of the brain only happens once the gut microbiome has returned to normal. The findings in this study are incredibly valuable in developing a simple and reliable diagnostic tool for concussions because, as the head researcher, Dr. Sonia Villapol, says, the gut “doesn’t lie”.
Next steps for researching the relationship between gut microbial changes and head injury include studying the findings in a larger sample size and in women soccer players, another group who has high rates of concussion.