Exploring the Mettle of Nettle

Normally, you encounter nettle as a stinging weed in the woods, or perhaps as a tea or supplement at a vitamin store. But a University of Maryland researcher’s project could help put the plant in the produce aisle.

A new three-year, $431,000 grant from the National Institute of Food and Agriculture is supporting a study by Diana Obanda, assistant professor in the Department of Nutrition and Food Science, to examine whether nettle can help fight chronic illnesses and prevent weight gain and insulin resistance by causing healthy changes to gut bacteria.

Previous studies of nettle extract as a supplement have shown potential benefits, but it has never before been scrutinized for its effect on the gut microbiome, a crucial and ever-changing balance of bacteria in the digestive tract that is central to immune response and overall health. It’s also never been studied as a “functional food”—one that provides specific health benefits beyond just energy and nutrients.

Such a food is “not a drug or a medicine, but it can prevent certain diseases,” Obanda said. “In my lab, I focus on functional foods that are important for the protection of metabolic health. They are not a substitute for exercising and living a healthy lifestyle, but they provide extra health benefits to provide an overall protective effect for better health.”

Obanda’s project proposes to find out how the changes in the gut microbiota, which are influenced by nettle, affect obesity mechanisms.

“The species of bacteria that increase or are reduced because of nettle in the gut—what do they do to affect the immune system and obesity? How do the phytochemicals in the nettle change or affect these bacteria species, and how do those mechanisms function to affect indicators for obesity and diabetes?” she said.

Obanda, who has been studying the plant for five years, has a special interest in plants like nettles and other functional foods like kale that are gaining popularity in the U.S., but have always been a regular part of the diet in countries like her home country of Kenya.

“Nettles have been studied for a very long time in different cultures, and they grow all over the world, really,” says Obanda.

Obanda worked with the Green Farmacy Garden in Fulton, Md., an expansive garden created by the late researcher James Alan Duke, an esteemed scientist at the U.S. Department of Agriculture and a firm believer in the medicinal benefits of foods. There, Obanda was able to gather authentic nettle for her preliminary work on the grant study. She has since planted some nettle at the UMD Research Greenhouse Complex to continue her work.

“I’m looking forward to forming collaborations with scientists across clinical science and public health to help translate this work into usable data for the general public health,” she said.