What if farmers knew how to grow crops to boost the levels of cancer-fighting nutrients they contained?
That, says Ilse Renner, would help turn the management of cancer away from treatment and toward prevention.
A doctoral student with Professor Vince Fritz in the College of Food, Agricultural and Natural Resource Sciences, Renner studied what conditions made cruciferous vegetables, mainly cabbage, ripe for producing a nutrient called glucobrassicin.
“We found, across multiple seasons of field work year to year, a consistent effect,” she says. “When there was less incoming red light than far red light, more glucobrassicin was produced.” Far red light has a longer wavelength than red light, and the effect appeared in one of two varieties of cabbage she tested.
In fall 2019, Renner was a finalist in the 3-Minute Thesis competition, where doctoral students had three minutes to explain the significance of their projects, minus props and industry jargon.
Borrowing a plant’s defense
When we eat a vegetable containing glucobrassicin, we also consume a plant enzyme that breaks glucobrassicin down into substances with anticancer activity, notably against estrogen-dependent cancers. Other cruciferous vegetables, like Brussels sprouts and broccoli, contain lots of glucobrassicin and the enzyme, but overcooking can destroy the enzyme. Called myrosinase, the enzyme helps plants defend against herbivores.
Much of the original work showing the cancer-fighting potential of glucobrassicin-rich vegetables came from the lab of the late University of Minnesota professor Lee Wattenberg. Wattenberg, who was known as the “father of chemoprevention,” demonstrated the nutrient’s value during feeding experiments with mice.
“Today, glucobrassicin is studied in the Masonic Cancer Center [at the University] to see how much is taken up from the diet,” Renner notes.
“Coming here I knew Professor Fritz worked with crops in relation to human nutrition,” Renner recalls. “I really liked tying plant physiology to the human aspect—that drew me to him specifically.”
Besides his role as professor in the Department of Horticultural Science, Fritz is an Extension vegetable horticulturist at the University’s Southern Research and Outreach Center in Waseca, Minnesota.
“He has a very applied focus,” says Renner. “The time I spent in Extension was very educational in terms of learning about land grant universities and the transfer of knowledge. It’s a situation a lot of graduate students don’t see, but I think they would benefit.”
Renner, who expects to receive her PhD in April, is leaning toward a career in industry.
“I like the area growing around indoor ag and farms,” she explains. “For me, the big thing isn’t necessarily a specific vegetable crop, but which chemical compounds we care about and which crops are best for producing them.”