Meet affiliated faculty Carol Johnston

Carol Johnston

The Swette Center for Sustainable Food Systems focuses on innovative ideas and solutions to the many challenges of current food systems. In this series, we’re sitting down with the Swette Center affiliated faculty to catch up on food systems, innovation and what makes a good meal. See the rest of the series on our Food Systems Profiles page.

Read on for an interview with Carol Johnston, associate dean and professor in the College of Health Solutions.

Question: How did you get interested in food systems issues?

I was at the University of Michigan as an undergrad, and Francis Lappé was coming to talk about her new book, "Diet for a Small Planet". I read the book and was surprised to learn about the environmental impact of meat production, and that’s when I became a vegetarian. As I moved forward I started to look at the vegetarian diet from a nutrition standpoint, because there are pitfalls but also there are benefits.

For example, a few years ago the American Psychiatric Association recommended eating fish twice a week to reduce the risk of dementia and depression, with the idea being that omega-3 fatty acids are good for the brain. I was wondering, what does this mean for vegetarians, who of course don’t eat fish? There was nothing in the literature at that point about mood states and vegetarianism. We found a population to study that was about half vegetarian and half omnivores, and low and behold, the vegetarians had no moodiness! They were the happiest. The omnivores were the moody ones!

After that we did some intervention testing, where we had omnivores restrict their diet to a vegetarian diet, and their moods improved too. So the theory is that that if you don’t eat meat, you don’t have as much of the arachidonic acid (omega-6) that needs to be countered by omega-3s. If you’re eating meat, you need to eat fish to counteract the inflammation caused by arachidonic acid that is present in the meat, but if you’re not eating meat, you don’t need the extra dietary anti-inflammatory omega-3s.

Q: Can you share a glimpse of your current research and how it applies to food systems transformation?

A: I’m working with Dr. Chris Wharton to look at protein quality in a vegetarian diet. The protein that comes from plants is difficult to assimilate because of the fiber that hinders the body’s absorption potential of protein. And beyond that, we’re looking at the carbon footprint of different plant-based proteins to figure out which protein source has the lowest carbon footprint, but the highest dietary quality. I think people will be very excited by the results, because it’s a totally new approach.

Q: What’s an innovation in the food systems world that you’re excited about?

A: We need to eat fresh and unprocessed foods get the biggest impact from the nutrients in the foods. In the 1990s, I was studying college student’s vitamin C levels. These students were having early symptoms of scurvy, and their vitamin C levels were really low. I asked them if they drank orange juice, and many said they did, so I thought, is something wrong with our orange juice?

I bought a variety of containers of orange juice at the grocery store and tested the vitamin C levels. It turns out that the closer you are to the expiration date, the lower the amount of vitamin C in the juice — and in some juices it was zero. And once you open the carton and allow oxygen to interact with the juice, you start to lose the vitamin C. So the issue is that the orange juice the students were drinking didn’t have much vitamin C! And still today, one third of Americans have a marginal vitamin C status, and orange juice remains the main source of vitamin C for people.

Frozen orange juice stabilizes the vitamin C, but in the 1980s there was a change in manufacturing to provide ready-to-drink “fresh” orange juice. But of course it’s not fresh — it was produced weeks ago, and the vitamin C has deteriorated. So we need to think about how manufacturing and processing affects the nutrition of our food.

Q: What’s your favorite food and why?

A: Jarlsberg low fat swiss cheese. I buy it in bulk, and it’s my main protein source. I eat it for breakfast and dinner. I’ll have some in the car on my way to work in the morning. Dairy is rich in vitamins, minerals and protein, and cheese is just a concentrated form of dairy. If you spread your protein consumption over the course of the day, it facilitates body protein synthesis, so I have some in the morning and at night.

Photo: Professor Johnston in her favorite place, the beach!