WASHINGTON Antioxidant vitamins are widely assumed to be cancer fighters even though research in smokers has found high doses may actually raise their risk of tumors. Now a new study may help explain the paradox.
Swedish scientists gave antioxidants to mice that had early-stage lung cancer, and watched the tumors multiply and become aggressive enough that the animals died twice as fast as untreated mice.
The study, released Wednesday, concluded that the extra vitamins apparently blocked one of the body's key cancer-fighting mechanisms.
The scientists stressed that they can't make general health recommendations based on studies in mice, but said their work backs up existing cautions about antioxidant use in people at increased risk of cancer.