Taking supplements full of antioxidants can actually help cancerous tumors grow

Solna, Sweden — Scientists have warned that taking vitamins or supplements can feed tumors and promote their growth. Common antioxidants, such as vitamins A and C, selenium and zinc, can stimulate the growth of blood vessels in cancer when taken in excess. The discovery surprised the researchers, as previous studies had shown antioxidants to be protective. While the Swedish scientists report that normal levels of antioxidants in food are safe, taking supplements containing additional antioxidants can fuel tumor growth and allow the disease to spread faster.

The study, conducted by a team at Karolinska Institutet, concluded that vitamin C and other antioxidants promote the formation of new blood vessels within lung cancer tumours. The study authors point out that this finding could apply to all types of cancer and its spread.

“We found that antioxidants activate a mechanism that causes cancerous tumors to form new blood vessels, which is surprising, since it was previously thought that antioxidants have a protective effect,” says study leader Martin Bergo, a professor in the Department of Biological Sciences and Medicine. Nutrition and Vice President, Karolinska Institutet, Sweden. “New blood vessels fuel tumors and can help them grow and spread.”

Antioxidants neutralize free oxygen radicals, which can damage the body and are commonly found in dietary supplements. However, excessively high doses can be harmful.

Professor Bergo adds: “There is no need to be afraid of the antioxidants found in regular food, but most people do not need additional amounts of them.” statement. “In fact, it can be harmful to cancer patients and people who have an elevated risk of developing cancer.”

The research team found that antioxidants reduce levels of free oxygen radicals, but when additional amounts are introduced, the reduction in free radicals activates a protein called BACH1. This, in turn, leads to the formation of new blood vessels, a process known as angiogenesis.

“Several clinical trials have evaluated the efficacy of angiogenesis inhibitors, but the results have not been as successful as expected,” says Ting Wang, PhD student in Professor Bergo’s group at Karolinska Institutet. “Our study opens the door to more effective ways to prevent angiogenesis in tumors. For example, patients whose tumors display high levels of BACH1 may benefit more from antiangiogenic therapy than patients who have low levels of BACH1.”

Using lung, breast and kidney tumors, they found that when BACH1 is activated by ingested antioxidants or by overexpression of the BACH1 gene, more new blood vessels are produced. However, these blood vessels were highly sensitive to angiogenesis inhibitors.

“The next step is to conduct a detailed examination of how oxygen and free radical levels regulate BACH1 protein, and we will continue to determine the clinical significance of our findings,” Wang concludes. “We will also carry out similar studies on other forms of cancer such as breast, kidney and skin cancer.”

The study is published in Journal of Clinical Investigation.

Southwest News Service writer Jim Liefman contributed to this report.

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