How much does your gut health impact your overall health? A lot, doctors say

You may be hearing a lot about the gut microbiome these days — it's been mentioned everywhere from wellness podcasts to the grocery aisle. Doctors are tapping into it to try and treat some diseases differently.

The gut microbiome is the community of all the bacteria and viruses in our intestines, including friendlier microbes that promote health as well as some foes that can cause illness.

One evolving procedure is the fecal transplant, where a small sample of stool from the colon of a healthy person is given to a recipient for therapeutic purposes. Despite the ick factor, they have been used to treat potentially fatal, recurring bacterial infections for which antibiotics have been less effective.

Now, doctors and researchers are looking to see whether fecal transplants can be used for other hard-to-treat illnesses.

Health Canada approved fecal transplants for recurrent C. difficile infections in 2015. Impacting the colon, these infections lead to diarrhea and, if recurring, dehydration that can wreak havoc on the body. The goal with the transplant is to have the healthy bacteria outcompete the C. difficile and wipe out the stubborn infection.

Overall, for recurrent C. difficile, fecal transplants were significantly more effective, greater than 85 per cent, compared with less than 50 per cent for antibiotics.

Dr. Nikhil Pai, a pediatric gastroenterologist and associate clinical professor at McMaster University in Hamilton, said antibiotics can create a terrible cycle.

"What ends up surviving after this scorched-earth antibiotic regimen are bacteria that cannot only make things worse, but can affect a lot of other things such as just general nutrition and metabolism," Pai said.

In adults, a 2023 review of clinical trials published by the respected Cochrane Library concluded fecal transplants may also help control Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease that harm the gut when the body's immune system mistakenly attacks itself.

Bruce Vallance, a pediatrics professor at the University of British Columbia, said inflammatory bowel disease is essentially chronic inflammation of the gastrointestinal tract, possibly triggered by the bacteria living in our intestines. It can happen at any age, he said.

"We're trying to figure out whether certain microbes are driving the disease and whether we could target those microbes, deplete them and hopefully remove them from the intestine so there's no longer any trigger for disease."

Some researchers are also looking into using fecal transplants for teenage anorexia nervosa, known for its difficulty to treat and high death rate. Research suggests there is a gut-brain connection, and scientists are finding there is an association between anorexia and imbalances in the gut microbiome, which could influence a person's behaviour. 

Vallance and his team are also studying whether certain microbes that may drive Crohn's and colitis can get through a key mucus layer in the intestines.

To that end, he's been working with doctors at BC Children's Hospital to take fecal samples and biopsies that offer a snapshot of what's going on in the human colon.