Study Boosts Selenium As Cancer Fighter Dramatic Drops In Illness Seen; Doctors Say More Tests Needed

A new study bolsters research touting selenium, a mineral found in seafood and liver, as a cancer fighter.

The study found that when compared with people who received a placebo, patients who took daily doses of selenium had 63 percent fewer cases of prostate cancer, 58 percent fewer colon or rectal cancers and 45 percent fewer lung cancers.

In the selenium group, there were 50 percent fewer cancer deaths than in the placebo group, researchers reported in today’s Journal of the American Medical Association.

But the researchers cautioned that their results need to be replicated because the study initially was designed to measure only whether selenium would help prevent skin cancer - and it didn’t.

Dr. Graham A. Colditz, an epidemiologist at Boston’s Brigham and Women’s Hospital, called the study “promising but preliminary.”

“If this possible magic bullet acts through mechanisms suggested by the authors, it is not clear why it should be specific to only some cancers,” Colditz wrote in a JAMA editorial.

And because 75 percent of the 1,312 subjects were men, additional research is needed, Colditz wrote.

Selenium, found in seafood, liver and vegetables grown in selenium-rich soil, is known to preserve the elasticity of body tissues and is important for the immune system.

Numerous studies in the 1970s suggested that selenium could prevent cancer in animals, but trials in humans have been less conclusive. Selenium is sold in health-food stores and touted by some as a treatment for everything from dandruff to cancer and AIDS.

The new study, led by University of Arizona epidemiologist Larry Clark, found that the mineral may prevent cancer by inhibiting tumor growth and inducing “suicide” in malignant cells. Clark said selenium might not have been effective in preventing new skin cancers because these malignancies have a mutation in a gene that regulates cell suicide.

They studied 1,312 patients previously treated for skin cancers. Half the patients were given selenium daily and half got the placebo for an average of 4-1/2 years. The average age of the subjects was 63.

Though the selenium dose of 200 micrograms was almost triple the recommended daily allowance, it was still within the limits of what the Food and Drug Administration considers safe and adequate, Clark said.