The use of medical imaging tests that emit
ionizing radiation—high-energy radiation that causes electrons to separate from their atoms or molecules—has skyrocketed in recent years, leading more doctors and patients to question not only whether certain tests are being
overused, but also whether damage caused by exposure can be minimized.
Several small but promising recent studies have shown that antioxidants could help reduce damage to DNA caused by radiation from these medical imaging tests.
“Radiation” is a word that evokes fear, but it’s important to realize that we are surrounded by
naturally occurring radiation at all times, including cosmic radiation from the sun and stars, as well as
radon gas released as soil and rocks break down.
These natural sources are referred to as “background radiation,” and levels can vary from place to place, but the
American Cancer Society estimates that, on average, Americans are exposed to about 3 millisieverts of radiation from natural sources each year.
Some level of exposure to ionizing radiation is just a normal and unavoidable part of life. In fact, we even rely on some radiation for our health, using ultraviolet radiation from sunlight, for example, to create vitamin D in our skin.
Interestingly, though, human exposure to radiation has risen significantly in recent decades, due to manmade sources.
Harvard Health explains: “Exposure to ionizing radiation from natural or background sources hasn’t changed since about 1980, but Americans’ total per capita radiation exposure has nearly doubled, and experts believe the main reason is increased use of medical imaging. The proportion of total radiation exposure that comes from medical sources has grown from 15 percent in the early 1980s to 50 percent today.
“Over 80 million CT scans are [now] performed in the United States each year, compared with just three million in 1980.”
There’s no question that medical imaging tests have revolutionized the diagnosis and treatment of many conditions and have greatly reduced the need for exploratory surgeries. They are an invaluable medical tool. But the huge increase in the number of higher-radiation dose tests, such as CT scans and nuclear imaging, has many patients and doctors wondering about the cumulative risk of repeated low-dose radiation exposure and its potential link to cancer development down the road.
Some medical images are more dangerous than others. For the chest area, a single CT scan, for example, exposes the patient to at least
150 times the amount of radiation than a chest X-ray does, according to
RadiologyInfo.org. And if contrast is used, the radiation dose is approximately doubled.
Ionizing radiation produces
free radicals, which are atoms or molecules that have an odd number of electrons in their outer shell, making them unstable and in search of another electron. Free radicals scavenge electrons from surrounding cells, in turn causing damage to those cells.
Antioxidants work to stabilize free radicals by donating an electron, thereby stopping the scavenging action of the free radical in its tracks. This is a normal process that is always occurring in the background of our ordinary life activities.
While most damage is repaired by the body’s own sophisticated cell repair mechanisms, a small amount is not. These unrepaired cells can contribute to causing cancer in the future. Problems occur when the number of free radicals overwhelms the body’s ability to neutralize them.
That’s why minimizing exposure to ionizing radiation, as well as other environmental factors that increase the number of free radicals, such as pollution, tobacco smoke, and toxic chemicals, is important.
It’s especially important for children and adolescents to avoid unnecessary radiation because they are still growing and therefore more susceptible to the damaging effects of radiation. They also have more years of life ahead of them during which damaged cells could become cancerous.
One large Australian
study, which analyzed the medical records of nearly 11 million children and adolescents who received CT scans between 1985 and 2005, found a 24 percent increased risk of cancer following a single scan, and an additional 16 percent increased risk with each additional scan. While the radiation doses of most CT scans today are likely lower than they were back in the 1980s and ‘90s, those numbers are still concerning.
With the increase in exposure to ionizing radiation has come an increased interest in ways to reduce related DNA damage.
Dr. Kieran Murphy, an interventional neuroradiologist, and colleagues at Toronto Western Hospital studied the effects of consuming an oral antioxidant cocktail containing vitamin C, lipoic acid, B-carotene, and N-acetylcysteine prior to exposure to ionizing radiation on five patients, compared to a five-patient control group.
They found the antioxidants had a significant protective effect on DNA.
The study, which was published in the
Journal of Vascular and Interventional Radiology in March 2017, concluded that “antioxidants may provide an effective means to protect patients and health care professionals from radiation-induced DNA damage during imaging studies.”
Murphy has spearheaded research in this area, and his company,
Cora Therapeutics, now sells an antioxidant formulation that is specifically designed to help reduce radiation-induced damage.
It’s important to note that the protective effects were seen when antioxidants were taken prior to imaging tests being done to reduce the damaging effects of free radicals on DNA—not afterward.
While questions remain about diet versus supplements, and the best type and amount of antioxidants to help reduce radiation-induced cell damage, including plenty of antioxidant-rich foods in the diet, such as berries, nuts, legumes, and cruciferous vegetables (such as broccoli, kale, and Brussels sprouts) may be an effective way to further reduce your risk.
