Studying Selenium

Fifty years ago, ranchers in central Oregon were losing livestock to white muscle disease. OSU animal scientist Jim Oldfield wanted to know why.

The disease is characterized by calcified muscle lesions that appear in newborn calves and sheep, causing heart failure and death. Oldfield planned a study to see if vitamin E supplementation might help. At the last minute, he decided to test selenium too.

The selenium worked; the vitamin E didn’t. Oldfield’s results were a breakthrough. “This discovery initiated a large volume of research on selenium that continues today,” said Phil Whanger, a recently retired OSU professor of agricultural chemistry, and part of a dynasty of OSU scientists studying selenium.

Much of Whanger’s research focused on one of the important antioxidant enzymes that require selenium for activity. White muscle disease results when cattle and sheep have diets deficient in selenium and aren’t able to make enough of these enzymes in their cardiac and skeletal muscle. Whanger’s work led to studies of pregnant women and the role of selenium in healthy human births.

Animals get selenium from the plants they eat; plants get selenium from the soil. Most of Oregon’s soils are selenium deficient, according to Wayne Mosher, who worked for more than 30 years in Douglas County as an OSU Extension livestock agent. “We found that selenium supplementation can create a huge difference for ranchers,” he said. For example “on the Warm Springs Reservation, one rancher’s calf crop was only about 40%. Another rancher who was supplementing with selenium and minerals had more like 100%.”

Jean Hall, an associate professor at OSU’s College of Veterinary Medicine, is the next generation of selenium researchers. She’s studying selenium as an immunonutrient in sheep, to find out if supplementing above the currently recommended levels can boost their natural immunity (in this case, their resistance to foot rot), and if organic selenium is better absorbed than inorganic selenium.

Hall is in frequent contact with all three professors emeritus—Oldfield (retired 1987), Mosher (retired 1979), and Whanger (retired 2001)—who continue to participate in current research efforts. “They may be retired, but they still contribute so much.”

There is a strong positive correlation between selenium supplementation and cancer prevention in humans—especially prostate cancer. There is also an increasing body of evidence suggesting that selenium can regulate thyroid function and improve immune function, both in livestock and in humans.

Mosher and Whanger are believers. Whanger takes selenium supplements and Mosher credits selenium for his good health. And then there’s Jim Oldfield, who, at age 87, still keeps regular office hours in the Animal Science Department and invites science writers to coffee.