Sweet potatoes are already packed with antioxidants and fiber, but zapping them with an electric current can boost these levels by as much as 60%, a new study shows.

The simple experiment doesn’t change the taste of the tuber either, says researcher Kazunori Hironaka, PhD, of the University of the Ryukyus, Nishihara in Okinawa, Japan.

Researchers bathed the sweet potatoes in salty water and then passed various currents through the water and spuds for five minutes. The team had previously tried the experiment on white potatoes with similar results.

Sweet potatoes have high levels of polyphenols -- even before they get zapped. Antioxidants such as polyphenols are thought to help mop up damaging free radicals, which have been linked to cancer and other diseases.
A 'Magic Trick'

Joe Vinson, PhD, says that the electricity releases the antioxidants that are bound in the fiber. “This is just kind of a magic trick.” He is a professor of chemistry at the University of Scranton in Scranton, Pa.

Similar results may occur after microwaving a sweet potato or even through the natural digestion process, he says.

Unlike other fruits and vegetables, “you can stick a wire in potatoes and they won’t fall apart.” Still, this is not ready for prime time. “You can’t advertise more antioxidants in sweet potatoes based on the results of this study,” Vinson says.

Connie Diekman, RD, calls the new approach “interesting.” She is the director of university nutrition at Washington University in St. Louis. “I understand that the electricity is a challenge to the plant and therefore it releases the antioxidants to protect itself,” she explains.

She is a big fan of regular, non super-charged sweet potatoes, which are loaded with nutrients in the first place. Eat more sweet potatoes by:

    Roasting, grilling, or baking them for different flavors
    Adding them to hash instead of white potatoes
    Using them sliced as a base for a poached egg
    Baking sweet potato pie

These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.