The main danger of vitamin C has been identified
A new study shows that antioxidants can stimulate the growth of blood vessels in cancerous tumors.A new study has found that antioxidants such as vitamins C and E activate a mechanism that stimulates the growth of new blood vessels in cancerous tumors. The researchers say their findings highlight the potential risk of taking antioxidant supplements when they are not needed.
To grow and metastasize, cancerous tumors need a constant flow of oxygen- and nutrient-rich blood. And this requires the formation of new blood vessels from existing ones - a process known as angiogenesis. When tissues lack oxygen (hypoxia), cancer cells in the affected area send chemical signals, prompting endothelial cells lining blood vessels to form new blood vessels.
A new study from Sweden's Karolinska Institute examined the mechanisms of angiogenesis and found that antioxidants play an unexpected role in tumor growth and spread.
Normally, antioxidants remove free oxygen radicals from the body's cells and reduce damage caused by oxidative stress. Oxidative stress is known to damage DNA and regulate the development of various cancers, including breast, lung, liver, colon, prostate, ovarian and brain cancer.
"You don't have to be afraid of antioxidants in regular foods, but most people don't need to take special supplements. In fact, it may be harmful for cancer patients and people at increased risk of developing cancer," the researchers wrote.
Previously, researchers found that antioxidants such as vitamins C and E accelerate the growth and spread of lung cancer by stabilizing the BACH1 protein. It is activated when oxygen free radical levels in the body drop. This can happen when supplemental antioxidants are added to the diet or when spontaneous mutations occur in tumors that activate antioxidant production.
The researchers found that BACH1 can also induce angiogenesis by a mechanism that does not require hypoxia. That is, tumors can form new blood vessels under normal oxygen levels. They also found that BACH1 is regulated similarly to hypoxia-inducible factor 1-alpha (HIF-1-alpha) protein, whose expression is involved in tumor growth and metastasis driven by angiogenesis. Therefore, the scientists hypothesized that these two proteins work together.
The study is published in The Journal of Clinical Investigation.