Q&A With a Gut Microbiome Scientist

Right now, you have trillions of microbes hitching a ride with you. In fact, it has been estimated that 90 percent of the cells that make up your body are not your cells -- they are bacteria, fungi and other "non-human" life forms. Scientists have just begun to understand the importance of this, and we now know that our unique make-up of microbes contributes to our overall health in astoundingly important ways.

For example, emerging evidence is showing that our gut microbiome may play a role in weight gain. Our first hint that there was a link between our gut bacteria and weight gain actually came from farming practices. Chickens given a low-dose antibiotic grow to be heavier. Scientists now know that reducing the diversity of gut bacteria in the chicken's body is likely what allows it to gain more weight. Can this be true in humans?

Enter the gut microbiome scientist. Corrie Whisner at Arizona State University is currently studying the role of the gut microbiome and its possible link to the notorious "freshman 15" -- the propensity of first-year college students to gain weight. Whisner suspects that the gut microbiome diversity is decreased during that "perfect storm" of bad habits that lead many students to add pounds. She expects to have data by the end of 2016, but she provided some insight into her research through a brief interview.

Q: Your research is looking at whether college students that gain the dreaded "freshman 15" have less diversity in their gut bacteria. What do you suspect is leading to less diversity in their gut bacteria?

A: I think that students' eating behaviors in college play a large role in changing their gut bacteria. Numerous studies show that fast food-rich diets increase weight gain via the gut microbiome. For many students, heading off to college means eating lots of burgers, fries and pizza, which definitely has an impact on the waistline and likely the gut microbiome. Furthermore, newer research is beginning to show that exercise also improves the diversity of the gut microbiome. Many students do not meet the daily recommendations for physical activity, which could be another factor influencing the diversity of gut bacteria.

Q: Is it difficult to get people to donate to your research, considering that you are asking for fecal samples?

A: Surprisingly, it is not as difficult as one might think to get fecal samples from college students. Our team is very enthusiastic about this research and I think that helps when telling potential participants about the study. More often than not, the students enroll because they are excited to move science forward and learn a bit about their own microbiome. We provide interested participants with a printout of their own microbiome profiles that includes fun facts about the most prevalent types. Many students have also told us that they might as well collect their stools for a little incentive when they would have flushed it away anyway. We are so grateful for their enthusiasm and effort!

Q: What three things would you suggest people do to improve or protect their gut microbiome?

A: 1. Feed your little friends well. You've got millions of little travelers inside your intestines that depend on you to feed them each day. Choosing foods rich in dietary fiber, like whole grains, fruits and veggies, is a surefire way to keep your gut bugs fueled and happy. Live an "on-the-go" lifestyle? Stock up on granola bars or yogurt that have prebiotics added to them.

2. Get some exercise. You've probably heard that regular exercise can improve regularity in the bathroom, but most of us don't attribute that to the gut microbiome. Recent research is starting to show that exercise might also impact the microbiome for the better. So take the stairs at work or park at the end of the grocery store parking lot to fit in a few extra steps each day. Your gut bugs will thank you.

3. Take it easy on the antibiotics. Most antibiotics lack selectivity and wipe out both good and bad intestinal bugs. Unfortunately, it takes time for the health-promoting microbes to get back to their normal levels again, and in the interim you might be putting yourself at greater risk for other infections. The good bacteria in our intestines can actually help fight off illnesses. So have your doctor do a thorough evaluation of your symptoms the next time you are sick and only take antibiotics if you really, really need them.

Q: How has your personal diet changed since you have been studying the microbiome?

A: I would say that I have a renewed interest in trying recipes that include vegetables with prebiotic fibers. Some of the foods that I have recently incorporated into meals more often are leeks, Jerusalem artichokes and onions. All of these foods are packed with inulin, which is a great non-digestible fiber that intestinal microbes love.

Melinda Johnson, MS, RDN, is the Director of the Didactic Program in Dietetics and a Clinical Assistant Professor for the Nutrition Program at Arizona State University. Follow her on Twitter @MelindaRD.