'Gut Check' study looks at intestinal microbes and their link to human health

LOGAN — Here's the poop: How much do you know about your own digestive system?

For example, did you know there are 10 times more bacteria in your body than you have human cells?

There are more than 1,000 varieties of bacteria that live within the human gut, and an average person can have about 300 varieties of the little critters living within them. Each type of bacteria not only supports one another, but supports the ability to digest food, stay healthy and, if a gut community is a bit off, perhaps gain weight or develop diabetes.

Utah State University professor Mike Lefevre calls the gut "the forgotten organ." But let's face it, most discussions about the digestive system can quickly deteriorate into toilet humor. Lefevre says it's serious stuff.

"It plays an important role in our overall health and survival. One of the things that it does is it scavenges extra energy out of our diet. It's thought that it can actually count for 10 to 15 percent of our daily caloric requirement, so things that we don't digest in the small intestine then goes down into the colon, and there, the bacteria basically derive warm energy from it," Lefevre said. It kind of works like a body's catalytic converter.

Studies have shown that the variety and health of the bacteria in digestive systems can be linked to not only inflammatory bowel conditions, like irritable bowel syndrome, but may also be linked to weight gain, diabetes, immune systems — even possibly to autism.

Lefevre works in the department of nutrition, dietetics and food sciences at USU, and what he studies, well, most of us flush down the toilet. "Oh, there's a lot of poop jokes," he said. "The puns are endless."

"People pooh-poohing certain ideas, it just never ends," added Janet Bergeson, a clinical study coordinator working with Lefevre. But they say it's all done in good humor.

The Gut Check study is being funded through the Utah Science Technology and Research initiative, or USTAR. It is a state-funded program to help support science research that has the potential for commercial use.

Specifically, Lefevre is looking at how certain gut bacteria, or microflora, interact with types of food people eat. The goal is to someday have doctors and nutritionists be able to customize a diet or probiotic mix specific to an individual.

That is when project Gut Check came into being. Lefevre's team of researchers have been studying the diets and microflora of northern Utah residents, doing a genetic analysis of bacteria to identify the types, and comparing that profile to a person's diet.

For about three days, subjects are asked to write down and photograph everything they eat. After four days, they are then asked to take a stool sample, freeze it and bring it to Lefevre's lab. A blood sample is also taken at the end of the week to measure a person's metabolism.

Subjects get $20, a battery of medical tests, a nutritional analysis and the sense that they are helping to advance science. Bergeson said many subjects open up about their bowel issues — something few people feel like they can openly talk about.

"It's so deeply personal," Bergeson said.

Other scientists are just beginning to realize the potential for research in this area. "We should think about these microbes and their collected genome as an extended portion of our own genomes," said Justin Sonnenburg, a microbiologist from Stanford University.

Michael Fischbach, a colleague at University of California San Francisco added that for a long time, pharmaceutical companies had only considered developing drugs to kill bacteria. He suspects in the coming years they will realize that they can develop drugs that can encourage the positive properties of some bacteria living in humans.