By Sara Bondell - July 02, 2019

Excess antioxidants—like vitamin E and vitamin C—may fuel the spread of lung cancer, according to two new studies.

Antioxidants come from two places: they’re in the foods like blueberries, dark leafy greens and chocolate, and the body also naturally produces them. “Because antioxidants play an important role in protecting our cells from damage, including damage to our DNA that could include cancer-causing mutations, clinical studies using antioxidant supplementation have been attempted, but these studies have failed to show protection from cancer,” said Dr. Gina DeNicola, a researcher in Moffitt Cancer Center’s Cancer Physiology Department. “In fact, one trial showed vitamin E supplementation actually increased prostate cancer risk.”

Dr. Gina DeNicola, researcher

The two new studies, one led by researchers at New York University and the other led by researchers in Sweden, showed how antioxidants can promote lung cancer metastasis and the reason behind it. Lung cancer cells can use antioxidants to spread in the body by activating a protein called BACH1. This protein presses several start buttons in the cancer cell which stimulates the uptake of glucose and the cancer to spread.

“These studies were performed in mice, and it remains to be seen whether high-dose antioxidant supplementation is associated with an increased risk of metastasis in patients,” said DeNicola. “It’s important to note that the amount of antioxidants obtained from a healthy diet rich in fruits and vegetables are likely not high enough to induce these effects. These foods have many beneficial effects and should be included in the diet. High-dose antioxidant supplements, however, should be used with caution, particularly given the established association between vitamin E and cancer risk in humans.”