n accurate but less-than-riveting title for Brett Finlay
and Marie-Claire Arrieta’s bestselling book for parents
published this past September could have been:
Enhancing Environmental Biodiversity for Optimizing Pediatric Gut
Microbiome Health. Instead, Dr. Finlay, a professor of microbiology at the University of British Columbia, and Dr.
Arrieta, an assistant professor of physiology and pharmacology at the University of Calgary, wisely decided on the
much snappier Let Them Eat Dirt: Saving Your Child from an
Publication of the book and associated media coverage from outlets as prestigious as the Wall Street Journal
and the Guardian newspapers are indicators of the growing recognition of the importance of microbiological life in the human
gut (the gut microbiome) and how it influences health – as well as the
important role played by Canadian researchers and universities in this
Once one gets over the “ick” factor of looking at the human digestive
tract and all the microbes that call it home – and the messy approaches to
treatment such as human fecal transplants – the subject area can be seen
as a fascinating and important one.
The incidence of food allergies, asthma and obesity has increased significantly in the last couple of decades in Canada and much of the Western world. In addition, Canada has the highest incidence of inflammatory
bowel disease (IBD) and irritable bowel syndrome (IBS) in the world.
Many are now looking at a symbiotic relationship between the gut microbiome and the immune system, mediated by factors such as an increased
use of antibiotics, as being responsible for this concerning trend. More
importantly, this research is pointing towards new potential preventive
therapies involving the gut to help not just digestive diseases, but everything from diabetes to asthma and even autism and mental health issues.
While interest in the bacteria, viruses, protozoa and fungi that inhabit
the human gut is of fairly recent vintage, Canadian researchers have been
involved for more than a decade in mapping out what some are calling a
new human organ. Investment in the area has escalated in recent years as
millions of dollars are directed towards funding networks, research chairs
and individual researchers – much of it coordinated through the Canadian Institutes of Health Research.
Why Drs. Finlay and Arrieta chose to write their book is explained in
the introduction, where they note: “This was such a new field, there was
no one source parents could turn to if they wanted to learn more. Even
as scientists in the field, we were stunned to discover some of the pro-
found roles … microscopic bugs have in normal childhood development.
No doubt many of these findings, and many more to come, will have a
profound impact on how we think about raising our children.”
marc ouellette is scientific director of the Institute of
Infection and Immunity at CIHR and one of two directors
(along with Philip Sherman of the Institute of Nutrition,
Metabolism and Diabetes) overseeing gut microbiome research at the funding agency. “We have known for a very
long time that there were a number of bacteria in our bodies, but we did
not recognize the diversity until unique sequencing technology was available,” Dr. Ouellette says.
“Basically, the human is an incubator of bacteria,” he says. The large
number of bacteria – mainly in the gut, but found throughout the body –
play positive roles in helping digest food and other functions related to
the immune system.
What has only become recognized more recently, he says, is that the
microbiome is associated with the development of almost all diseases. In
addition, says Dr. Ouellette, “there is also a clear link between the microbiome and some of what happens in your brain” through what’s called the
enteric-brain, or gut-brain, axis.
He says research interest in Canada really started in about 2008,
when a CIHR conference was held to focus on this emerging field. This
was held in the context of the ongoing Canadian Microbiome Initiative
created a year earlier to provide a framework for microbiome research
and set research priorities.
Dr. Ouellette says early work focused on cataloguing the bacteria
present in people with conditions such as IBD and asthma versus those
in the healthy population – although it was also recognized that there are
large variations in the type of bacteria within healthy individuals. “Now
we’re more at a stage where we’re starting to try to change the microbiota
… either by food intake or probiotics or other approaches, to have some
effect on pathology.”
While early CIHR support in this area came through catalyst grants
and a large $15.5-million grant to support research teams, Dr. Ouellette
says more and more investigators are now being funded through open
competitions. Through these open grants, he says, more than $6 million
annually in Canada is going towards microbiome research.