Our exposure to radiation from space (cosmic radiation) is significantly increased when flying at altitude. This blog explains why this is a genuine issue for frequent flyers and airline staff and describes how the risks can be reduced by sensible nutrition and lifestyle measures.
What is cosmic radiation?
Cosmic radiation consists of a mixture of high-energy particles and energy waves that continually penetrate onto the Earth atmosphere from outer space. Most come from our sun and levels can significantly increase after a large solar flare. According to Simon Swordy from NASA most particles are hydrogen nuclei, some are helium nuclei, neutrons and the rest heavier elements.
Is cosmic radiation is a concern?
The Earth’s atmosphere acts as a giant magnetic shield, blocking most of the cosmic radiation from reaching our planet. The ones that make it through to the Earth’s surface have low energy and are harmless. Otherwise, of course, we would not be here to discuss these things! However, where the atmosphere is thin, i.e. the further up you go, the more cosmic radiation exposure.
Why don’t planes fly lower?
The obvious solution would be for planes to fly at lower altitudes. Not withstanding the noise pollution, this would be less efficient. Planes would use more fuel, have a shorter range and cost more as the thinner air allows planes travel more easily. The “sweet spot” of flying is between 35,000 and 42,000 feet; too high and the oxygen becomes too sparse to fuel the engines, too low and the air resistance is greater.
How can cosmic radiation affect health?
Cosmic radiation produces ionising free radicals in our cells that can damage its normal function leading to ageing and more importantly damage DNA causing mutations that can eventually lead to cancer. The International Agency for Research on Cancer (IARC) considers neutrons, a major contributor to cosmic radiation at flight altitudes, to be a human carcinogen.
Who is more at risk?
Because there are so many other factors, which may explain the increasing risk of cancer (now affecting 1:2 of the population), it is always difficult in clinical studies to precisely link cosmic radiation to cancer. It has been suggested that female flight attendants have an increased incidence of breast cancer [Young] but they also have regular disruption of their circadian rhythm, which is also can increase the risk harmful. Nevertheless, because of their time spent in Earth’s upper atmosphere, aircrew can be exposed to several times the radiation levels of ground-based staff. The increased exposure also applied to frequent flyers depending on the ambient radiation levels at the time and duration of the flight. For example, flying round trip from New York to Tokyo seven times a year may easily put a passenger above the allowable levels of exposure that are enforced as a matter of law for medical and industrial facilities where radiation is encountered such as nuclear power stations.
Measure your cosmic radiation risk?
It is possible to estimate your exposure using this online calculator. When considering the results, bare in mind the International Commission on Radiological Protection recommends an effective dose of <20 millisieverts (mSv) per year for radiation workers, and 1 mSv for the public so if you are above this extra protective measures should be considered.
Other than flying less frequently, there are several nutritional and lifestyle measures, which have been shown to reduce markers of DNA damage and therefore may help mitigate the effects of carcinogenic ionising radiation:
- Avoid additional carcinogens when flying. It has long been know that combining different carcinogens can have a synergistic (even higher risk of DNA damage). Stopping smoking on flights was a very sensible move but if you are a smoker avoid the urge to smoke the day before or after a long flight. There is a long list of carcinogenic foods but the main culprits are superheated sugary snacks, burnt meat products and heavily processed food – read more about carcinogens and how to avoid them.
- Improve your exercise levels – As well as being very healthy generally, exercise specifically enhances the production and efficiency of antioxidant enzymes (superoxide dismutase and glutathione). It also enhanced the efficiency of DNA repair mechanism. It would be a good idea to take part in an exercise activity in the days before a flight – read more about the biochemistry of exercise.
- Reduce your risks of chronic inflammation. Although we need an appropriate inflammatory response to protect us from infection, our body’s are exposed to so many toxins and stress that our inflammatory system is in constant overload – these excess inflammatory cytokines drive the conversion of normal cells to cancer cells. – Read how to reduce chronic inflammation.
- Boost your polyphenols – these are the natural compounds found in plants, which give them their taste, colour and smell. Polyphenols have enormous health benefits ranging from reducing the risk of diabetes, heart attacks, dementia and cancer. As well as increasing your fruit, vegetable, tea, mushroom and nut intake it would be worth giving yourself a boost with a natural polyphenol rich whole food supplement for a few days before and after you fly.
- Increase your dietary antioxidant vitamins (Vitamin A, Vitamin E & Vitamin C ) within healthy whole foods. Unlike, polyphenol rich supplements mentioned above, there is no evidence that taking these in supplement form are helpful and they may increase normal levels which could be harmful – read more about serum vitamins.
- Ensure a healthy gut. A healthy immune system is very dependent on an optimum gut flora. Occasionally the balance between these friendly bacteria and harmful bacteria is upset – especially when travelling – a good quality, multi strain probiotic supplements can help to restore this balance – read more about probiotic supplements
by Madeleine Williams
Giardi M Preventtive value of nutraceuticals against ionizing radiation induced oxidative stress in frequent flyers Int J Mol.Sci 2013, 14 17168-17192.
Young L et al. High dietary antioxidant intakes are associated with decreased chromosome translocation frequency in airline pilots. Am J Clin Nutr 2009;90:1402–1410.
Gassmann A et al. Have female flight attendants an over-risk of breast cancer? Gynecol Obstet Fertil. 2015 ;43(1):41-8.
Thomas R et al. Polyphenols in cancer prevention and management. British Journal of Medical Practitioners 2014 7(1), 2-9.
Thomas R & Kenfield S et al. The Biochemistry of Exercise relevant to cancer prevention. British Journal of Sports Medicine 2017;51:640-644.
Thomas R et al Polyphenol rich nutritional supplements and prostate cancer – The NCRN UK POMI-T study .2014 17, pp180-6