As a registered dietician, every time I begin a talk or a client session with "better nutrition is actually simple" I get looks that range from incredulous, to hopeful, to (frankly) pissed off. Read
Maybe your business requires you to travel cross-country to consult. Perhaps you have an aging relative who lives far away and you fly frequently to see her. Or maybe you get a true vacation like the one I am on today, visiting Prague with a daughter who is studying abroad.
Flying may bring up issues of security, lost luggage and time schedules, but do you consider radiation exposure? Are you pregnant or exposed to other sources of radiation like medical CT scans or work hazards? If so, it's important to understand your radiation risks.
First, a few basic facts.
- The average amount of radiation a person in the US receives from all sources averages 6.2 mSv (milliSievert) a year.
- People who have jobs working with radioactive materials like nuclear facilities and hospitals are permitted exposures up to 50 mSv yearly.
- During pregnancy, it's recommended to limit exposure to 5 mSv during the entire pregnancy and no more than 0.5 mSv during any month.
- Only about 8% of our radiation exposure usually comes from cosmic rays, with more from smoking, contaminated air, food, and water, exposure to radon, where we live (the higher the altitude, the greater the exposure), proximity to nuclear and coal-fired power plants, and medical testing.
Flying may increase radiation exposure in two ways:
- Scanners for security testing are permitted to use up to 0.1uSv per scan. (Note: that's a micro not a milli Sv, so it's a very small amount.) It has been estimated that there might be one additional cancer death per 200 million security scans.
- Flying itself brings us closer to cosmic rays with less protection from the atmosphere. The intensity of cosmic radiation may be 100 times greater flying than on the ground. It increases when we fly based on factors such as: the plane's altitude, the plane's proximity to the poles of the earth, the length of the flight, and the presence of solar flares. A polar crossing saves a lot of fuel costs but increases the radiation. A flight from Chicago to Beijing over the polar cap is estimated to give you the same dose of radiation as two chest X-rays.
Is any of this really an issue?
In the US, flight crews (including pilots and attendants) are classified as having jobs with occupational exposure to ionizing radiation. Pilots with years of flying experience have been shown to have increased chromosomal damage. The true health risk has been hard to demonstrate, as cancers of the thyroid, breast, and bone marrow can take up to 30 years to manifest. A few studies suggest increased risks of breast cancer and melanoma in flight crews serving many years on many flights.
Recommendations have also been made to consider frequent flyers as at occupational risk if flying over 100,000 miles a year, an amount that may equal 20 extra chest X-rays a year.
Can anything be done to limit damage from the radiation exposure?
There is limited research on the topic but I offer three suggestions:
1. Eat an antioxidant “rainbow” plant-based diet while flying.
A study of 82 veteran pilots measured chromosomal damage and correlated the results with dietary questionnaires. Researchers found that eating foods loaded with antioxidants such as fruit and vegetables, (specifically citrus fruit and green leafy vegetables), were associated with much less chromosomal damage.
2. Consider an anti-oxidant vitamin.
Dr. Kedar Prasad, an expert in radiation safety in Denver, was contacted by the US after 9/11 to develop a supplement to protect troops if a dirty bomb were to be used. Thankfully this has not happened, but his research in animals and humans showed that taking a combination of anti-oxidant vitamins could reduce radiation damage. This idea has been commercialized for flyers and workers exposed to radiation by a company called Premier Micronutrients. I have used their BioShield-Radiation packet before flying for several years and the data they have showing reduced oxidative damage, increased immune function, and protection from DNA damage is impressive.
3. A variety of other food-based items have been suggested for flying based on limited human and animal data.
Spirulina was used for some children exposed to radiation in Chernobyl. Other chorophyll-rich foods like chlorella, kelp, and seawood may be of help. I know some very savvy frequent fliers who take a handful of spirulina and chorella tablets before flights. Zinc-rich foods (eg. wheat germ and pumpkin seeds), licorice, goji berries, turmeric, rosemary, green tea, and the polyphenols resveratrol and quercetin (found in apples and onions), have all shown some benefit in experiments.
In some sense, just as Icarus in the classic Greek legend paid a price for his desire to fly close to the sun, so do we. Overall, it's a negligible concern for most of us. The strategies suggested here are generally healthy ones to add to your daily routine, and specifically when you fly. I wish you good health and long years. (I'm off to relax with a cold Pilsner while I enjoy the low-radiation train ride to Berlin.)
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