In the neuroepigenetics course Assistant Professor Monica Dus teaches, students read scientific papers and discuss them in class. “In a way,” Dus says, “the topics of the papers don’t matter. The goal is to teach students how science is done and how to critically evaluate it.”
In the first half of the winter 2020 term, Dus’s students worked through the papers she had included on the syllabus. But halfway through the term, in the middle of March, Dus started to notice a lot of papers about COVID-19 were appearing online.
The COVID-19 papers Dus had started to see were preprints, full drafts of research papers that had not yet been peer reviewed. Before they are published, scientific papers typically pass through a formal peer review process that evaluates the caliber of their research and critiques their conclusions – a valuable process that takes time that the response to COVID-19 lacked. The pandemic was already happening, and researchers and doctors were desperate to share their data as quickly as possible.
Dus asked her class if they’d like to read the COVID-19 preprints instead of the papers she’d initially assigned, and the answer was overwhelmingly yes.
“I think there were around 1,000 preprints, and I pretty much went through all of them—reading the abstracts, trying to pick those that were closest to the techniques and topics that I felt my students would understand,” explains Dus, who teaches in the Department of Molecular, Cellular, and Developmental Biology. “Because it's a molecular genetics class, the papers we read were about the virus’s mechanisms, its structure, what the genome of the virus looks like, where it came from, what effects it has on the molecular level on the body. It was really great to be able to have that science at our fingertips—especially at the beginning of the pandemic, when there was so much anxiety and fake news out there.
“To me, it seemed like there was no better way to understand why doing good science really mattered. These preprints could help me teach students not just how to do science, but why we should do it," she says. "I conduct research because I love it and because I love to discover new things. But I also do science because it fills me with hope for a future that I can make better, and I wanted my students to have that hope, too.”
The Dus lab studies how sugar alters our sensory perception of sweetness and changes the way our brains process rewards. They want to understand whether these changes to our brains can make us more likely to be obese.
Research from Assistant Professor Monica Dus’s lab shows that eating a whole lot of sugar changes our brains, dulls our sense of sweetness, and leads us to consume more calories than we need. As sugar and flour disappeared from grocery shelves almost as quickly as hand sanitizer and toilet paper, Dus wonders what effect eating all this sugar will have on our brains.
LSA: In your lab, you explore whether sugar changes the physiology and biochemistry of the brain. What is your take on all of the baking people have done since we have been sheltering in place?
Monica Dus: I know, right? There's no flour anywhere! No chocolate chips. What happened to the Keto and Paleo diets?
There is pretty good evidence that sugar can be quite comforting and some types of foods are special to us on a genetic level because of the way we are wired. Our taste receptors, the way the taste of something sweet feels on the tongue, these things are wired to our brains to release feel-good chemicals. We're not wired to love broccoli. I haven't heard of a broccoli shortage!
LSA: You have found that when people eat a lot of sugar, it dulls their experience of sweetness. Can you explain how that works?
MD: We found that giving animals like fruit flies and rats high sugar diets decreases their perception of sweetness. Other people have done research in humans looking at changes in taste with different levels of sugar or salt or fat in your diet, and there is substantial evidence that the more of these three things you eat, the less you can taste them. And so the idea is that this decrease in taste perception might also lead to a decrease in the effects you feel in your brain—the pleasure, and the expectations of pleasure, that you might get.
I was actually just thinking about this. I'm pretty much baking every other day—cookies and scones and pizza. It would be really amazing to study how these quarantine changes in our diet have affected us. I know people that have said they've already put on a few pounds, but I think the question is whether these changes in taste are persistent. In fruit flies, they are persistent: They sort of rewire the way taste works in them forever. But maybe in humans the changes are not persistent, and they will go away after we all go back to keto or paleo and running six miles every day.
But for me the interesting part is this idea of emotional eating. When times get tough, we are drawn to comfort foods. Our love for food is genetic, and we can't really do much to change it unless we change our food supply.
Does your research have a corollary branch about emotional eating—the biological basis of that?
MD: Yes. We have a paper that looks at the changes in dopamine release in the brain with a high sugar diet. In that paper, my student who just defended her dissertation showed that because the fruit fly cannot sense the sweetness, the reward the brain sees is lower, which leads the fruit fly to eat more sugar to satisfy its earlier expectation.
A lot of people are anguishing about gaining weight. Do you have advice for people about monitoring their sugar intake?
MD: I feel like people should just be kind to themselves. If we were wired to find comfort in sugar, this is the time to give in to biology and find comfort. This isn’t the time to worry about gaining a few pounds. A few pounds are definitely not going to hurt anybody. My advice would be to be kind to yourself and those around you instead.
- Please visit the University of Michigan’s response to novel coronavirus COVID-19 for the latest information.