OREGON STATE UNIVERSITY

Zinc Deficiency Could Lead to Cancer

07/15/2008

CORVALLIS, Ore. – Zinc, an essential nutrient found in every cell in the human body, may also be a key component to fighting prostate cancer.

A recent study by Oregon State University researchers shows that zinc deficiency in the prostate leads to DNA damage as well as inhibition of the cell’s ability to repair itself.

Emily Ho, a researcher with the Linus Pauling Institute and an associate professor in the Department of Nutrition and Exercise Sciences at OSU, is the principal investigator of the study, published recently in The Journal of Nutrition. A team of graduate students, led by recent OSU alum Michelle Yan, conducted the research. Ho’s main area of research is on the dietary prevention of prostate cancer. Her lab is conducting human trials on the effects of broccoli sprouts as a cancer-fighter.

The prostate has the highest levels of zinc of any soft-tissue organ in the body, Ho said. “Increased DNA damage increases your cancer risk,” Ho said. “When we took zinc out of the cells, there was twice as much DNA damage as in normal cells. It’s a double whammy because we also saw that the zinc deficiency impairs the mechanism that helps repairs that damage.”

Ho said about 10 percent of Americans do not get enough zinc in their diets. In the elderly, she said that number shoots up to about 50 percent that are at risk for zinc deficiency.

“Many elderly people tend to eat less lean protein and zinc-rich foods, and the absorption of zinc decreases as we age, as well,” she said.

She said most people should get about 11 milligrams of zinc in their diet daily. Ho is an advocate for getting vitamins through dietary means whenever possible. Zinc is found mainly in unprocessed lean meats and shellfish. Oysters have some of the highest amount of zinc. Many vegetables contain zinc; unfortunately a compound called phytate binds zinc in the stomach so that the body doesn’t absorb the zinc as well and instead excretes it.

“Vegetarians are at more risk of being zinc deficient,” Ho said. “It wouldn’t hurt for vegetarians to take a good daily multivitamin to make sure they are getting those 11 milligrams per day.”

Ho cautioned against consumers rushing out to buy zinc supplements. Like any supplement, too much can also be a bad thing. Ho said more than 40 milligrams of zinc daily can be dangerous, and some studies point to high levels of zinc intake causing cancer instead of preventing it.

“There is no magic bullet,” Ho said. “A good balanced diet is always a starting point.”