Antioxidants to Protect Against Radiation

In 2022/2023 the number of patients who had CT scans in Canada was approximately 6.5 million, which is 47.7% increase in the past decade. (1) In 2007 Brenner estimated that 1.5 – 2.0% of all cancers in the US are caused by the irradiation from CT scanning. (2) Furthermore, in people with a BRCA mutation receiving chest X-rays or CT scans before they’re age 30, they have a 1.5-4x higher probability of developing breast cancer than the rest of the BRCA population. (3) Thus, with potential risks of increasing imaging, such as CT scans, are well known.  Although we are all exposed to radiation from natural resources (approximately 1 mSv/year, depending on where we live), the amount of additional radiation from artificial sources, may build up over time. We know that this risk is a concern based on the generation of free radicals and hydrogen peroxide.  

See the following examples of levels of artificial radiation below (4):

• Chest CT= 7 mSv
• Chest Xray = 0.1 mSv
• Cross-Canada flight= 0.02 mSv
• Dental x-ray= 0.005 mSv

This carcinogenic risk from medical imaging is traditionally mitigated by external factors such as shielding, using the lowest possible radiation dose, and only performing scans when necessary. Unfortunately, there is less discussion around internal factors that may minimize DNA damage such as oral antioxidants to scavenge free radicals. Appropriate antioxidant premedication may significantly reduce DNA injury after imaging studies. (5,6) More evidence is needed to determine if this translates to reducing the excess cancers caused by imaging. Overall, this approach has many advantages including its low cost, ease of administration, and safety. 

Several antioxidants can be considered for reducing the free radicals generated by medical imaging, including N-acetyl cysteine (NAC), vitamin C, vitamin E, carotenoids, glutathione, and alpha-lipoic acid. Ideally, the antioxidants are administered to achieve peak blood concentrations at the time of the radiation exposure. This can be estimated by looking at the pharmacokinetics of the antioxidant – the profile of how it is absorbed, metabolized, and excreted from the body. Many antioxidants like NAC, vitamin C, and melatonin are absorbed and excreted rapidly, which allows for dosing shortly before the radiation exposure. Contrarily, others like glutathione and lycopene can take days of build to peak concentrations.

The use of antioxidants to protect against radiation exposure from medical imaging should be individualized. Which antioxidant, its dose, and the timing of administration may differ based on each person’s medical history, concurrent medications, and health goals.

Further research is needed to confirm a reduction in DNA damage following medical imaging with oral antioxidant use, but preliminary studies are promising, and for many this approach could be considered after a discussion with their physician. 

For assistance on how to further support your patients undergoing cancer treatments, please consider the Advanced Integrative Oncology Palliative Care Course by the Integrative Oncology Institute.