When Antioxidants Could Hurt

Antioxidants appeared to encourage cancer metastasis


For years, people have praised foods high in antioxidants, such as blueberries, as healthy. Despite their potential health benefits, dietary antioxidants may not be the right choice for cancer patients.

A new study found that some cancer cells may benefit more from antioxidants than regular cells. The authors of this study suggested that dietary antioxidants may accelerate metastasis — the spread of cancer from one part of the body to another.

Most cancer patients die as a result of metastasis, according to a press release about this research.

To conduct this study, researchers at the Children’s Research Institute (CRI) at UT Southwestern transplanted melanoma skin cancer cells from patients into specialized mice. After administering antioxidants to some of the mice, these researchers found that cancer in the mice that had received the antioxidants metastasized much faster than in the mice who had not received antioxidants.

"We discovered that metastasizing melanoma cells experience very high levels of oxidative stress, which leads to the death of most metastasizing cells," said lead study author Dr. Sean Morrison, CRI director and Mary McDermott Cook chair in pediatric genetics at UT Southwestern Medical Center, in a press release. "Administration of antioxidants to the mice allowed more of the metastasizing melanoma cells to survive, increasing metastatic disease burden."

Dr. Morrison and team suggested that cancer patients may need to supplement their diets with pro-oxidants, not antioxidants. More research is needed before experts make recommendations on this topic.

Still, Dr. Morrison said, "The idea that antioxidants are good for you has been so strong that there have been clinical trials done in which cancer patients were administered antioxidants. Some of those trials had to be stopped because the patients getting the antioxidants were dying faster. Our data suggest the reason for this: Cancer cells benefit more from antioxidants than normal cells do."

This study was published Oct. 14 in the journal Nature. The Howard Hughes Medical Institute, Cancer and Prevention Research Institute of Texas and donors to the Children's Medical Center Foundation funded this research. Conflict of interest disclosures were not available at the time of publication.