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Here's what to do about radiation exposure on airplanes [1]
['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']
Date: 2023-11-17
{this post was originally published on my Substack called Examined, but a few Kos readers asked me to share here, even though not very related to political ideas! Enjoy}
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The Earth’s magnetic field shelters life from the blazing radiation of the universe. Our atmosphere absorbs a significant amount, too. This combined shielding is so good that despite a sizzling galaxy we humans only get about 5% of our annual radiation exposure from the cosmic sources up there. But flying in an airplane puts us at very high altitudes, with less atmosphere above to deflect and absorb radiation. The length of the flight, the altitude of the plane, the proximity to the poles, and any solar events like flares all affect how much radiation we get. Airport security scanners also use a small amount of radiation. Does all this add up to something we should worry about? Should we do anything to further protect ourselves?
Welcome to part three of a nuanced (and somewhat neurotic) discussion of health safety on airplanes. While there are many considerations here, we are focusing on just three that came up in the examining room: infections, blood clots, and radiation exposure.
In this post I aim to reassure us that the amount of radiation we receive from airport to airport and in the skies between is generally nothing to worry about. However, it’s not zero, and I argue that it is worth exploring some ways we might reduce the oxidative, ionizing damage our cells and DNA sustain from all sources of radiation. How do the antioxidants in healthy foods work, and might they be of some special value after radiation exposures? Should flight attendants be handing out blueberries instead of pretzels? Did you know that bananas are among the most radioactive foods we can eat?
Ideas, clinical studies, and intuitive conclusions about how to mitigate the effects of radiation on our bodies while in the stratosphere are even more applicable here on solid Earth, too.
And finally I’ll conclude with a master checklist derived from this series! This post is as long as a double article, so come back to it if you don’t have time now.
Where does the bulk of our radiation exposure come from?
We are exposed to various sources of radiation, with the primary contributors being natural background radiation (49%), which includes cosmic rays, radon gas, and terrestrial radiation from elements like uranium and thorium. Allowing for differences in location, natural background radiation can be further broken down by source:
cosmic rays 5-10%
radon gas 55-60%
elements like uranium and thorium 30-35%
Medical procedures, including X-rays and CT scans, account for approximately 48% of human radiation exposure! This always astounds me.
Man-made sources, such as nuclear power plants and industrial activities, only contribute around 2% of the radiation humans are exposed to. The remaining 1% comes from consumer products, like tobacco and certain building materials, as well as environmental sources like nuclear weapon testing fallout and contamination events. Unless you live in North Korea or Fukushima.
What are the harmful effects of radiation?
Like most things in the universe, it’s the dose that makes the poison. Throughout our lives we are constantly exposed to radiation. Cumulative damage occurs naturally. Ionizing radiation interacts with oxygen-containing compounds in our bodies to produce free radicals and reactive oxygen species (ROS). ROS are also a by-product of normal cell metabolism, and at low levels do benefit some physiological processes, including pathogen removal, wound healing, and tissue repair. However, excessive reactive oxygen species seriously affect balance in the body, and end up “attacking” important biological molecules like proteins and DNA. This can accelerate cardiovascular disease, mitochondrial damage, aging, and increase the risk of cancer.
Like Star Wars and yin-yang, there is a balance in the force. Our bodies use antioxidants to neutralize those excessive reactive oxygen species. Or more precisely: “An antioxidant is a molecule stable enough to donate an electron to a rampaging free radical and neutralize it, thus reducing its capacity to damage. These antioxidants delay or inhibit cellular damage mainly through their free radical scavenging property.”
Our cells can make many antioxidants naturally, and a healthy diet full of fruits and vegetables provides the rest.
How much radiation do we receive from the security scanners?
Metal detectors use magnetic fields without ionizing radiation, and these are very safe. These are the goal posts you might walk through at the airport.
Millimeter wave machines use non-ionizing radiofrequency waves. Waves reflect off the body and back to the machine. Millimeter wave scanners emit far less energy than a cell phone, and are very safe. They look like this to the right:
Backscatter X-ray machines have mostly been replaced in the U.S. These scanners used a small dose of ionizing radiation in the form of X-rays, most of which scattered away from the body surface being checked. One scan equaled the amount of cosmic radiation a passenger would receive during just two minutes of flying, and therefore the risk was very, very low. Problems with privacy and nude imagery were not fixed by the manufacturer as mandated by the FAA Modernization and Reform Act of 2012, so these scanners were replaced by the TSA in 2013. Europe banned them in 2012 out of an abundance of caution with X-rays. So there’s no more of the kind of imaging producing a whole body nude as seen at the top of this post.
All of this leads us to our first check box:
☑️ When it comes to airport scanners and radiation risk - chillax
How much radiation do we receive while flying in airplanes?
Instead of the usual radiation quotes and comparisons to X-rays, I’m going to pull from an excellent article in Scientific American. This article was written by Dr. Timothy Jorgensen, Director of the Health Physics and Radiation Protection Graduate Program and Associate Professor of Radiation Medicine, Georgetown University. It gives a clinically meaningful framework instead. I mined the article and can share these simple equations:
The radiation dose rate at a typical commercial airline flight altitude (35,000 feet) is about 0.003 millisieverts per hour .
By multiplying this dose rate by the hours of flight time , we can estimate the cumulative radiation dose received from each fight.
An overall cancer risk rate of 0.005% per 1 mSv of radiation exposure is a reasonable and commonly used estimate.
The risk of developing any type of cancer in life is about 40%, while the risk of dying from any cancer is about 20%. Women fare only slightly better than men.
So here is a sample calculation. Let’s say you fly from Philly to San Francisco, and then back again. Your total flight time is 13 hours.
(13 hours) X (0.003 mSv/hour) = 0.039 millisieverts of radiation received
(0.039 mSv) X (0.005% cancer risk / 1 mSv radiation exposure) = 0.000195% additional risk of developing cancer.
So instead of your risk of developing any kind of cancer being 40%, it is now 40.000195% from that flight.
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I recall this same kind of risk estimate in another article I read as applied to coronary artery calcium scans (CAC). These scans are sometimes used to screen for calcified plaque burden in the coronary arteries. These scans expose us to 1 mSv of radiation. “Based upon current estimates, a single CAC scan at 1 mSv would increase the lifetime risk of fatal malignancy by 0.005% for a number needed to harm of 1 out of 20,000 patients.”
Which leads us to the next check box:
☑️ Don’t worry about the radiation received on a flight. Calculating your added cancer risk, both in terms of individual and cumulative flights, leads to numerical reassurance.
[ 🙂 Examined presents vital and overlooked ideas your family doctor might share — if only we had more time. If you have time, sign up and join me for more articles I write that are like this 🙂 ]
What about that banana comment earlier?
A banana can emit 0.0001 mSv of radiation. To put that in context, you would need to eat about 100 bananas to receive the same amount of radiation exposure as you get each day in United States from natural radiation in the environment. 100 bananas will cause some serious hyperglycemia and high potassium levels, so don’t do that.
Should we start taking antioxidant supplements like vitamin A, C, E, and beta-carotene?
According to a review of all the important studies: “Although diets high in vegetables and fruits that are rich in antioxidants are associated with a reduced risk of cancer and cardiovascular disease (CVD), there is no evidence to support the use of antioxidant supplements to prevent cancer or atherosclerotic CVD.”
Studies have repeatedly shown that getting the benefits of antioxidants is not a reductionist proposition in a pill. We have to eat the whole fruits and vegetables that are rich in them.
Excessive supplementation can also tip the balance towards harm. For example, doses of vitamin E in excess of 400 units daily have been associated with increased all-cause mortality. Vitamin C can cause kidney stones. Beta-carotene supplementation increases the risk of cancer.
We need to eat the whole package. A strawberry has vitamin C, but also a whole bundle of other substances like flavonoids and proanthocyanins among other polyphenols. Harvard’s school of public health has a great article about antioxidants, and here’s a quick quote:
Excessive free radicals contribute to chronic diseases including cancer, heart disease, cognitive decline, and vision loss. This doesn’t automatically mean that substances with antioxidant properties will fix the problem, especially if they are taken out of their natural context. The studies so far are inconclusive but generally don’t provide strong evidence that antioxidant supplements have a substantial impact on disease. Keep in mind that most of the trials conducted have had fundamental limitations due to their relatively short duration and inclusion of people with existing disease. At the same time, abundant evidence suggests that eating whole fruits, vegetables, and whole grains—all rich in networks of naturally occurring antioxidants and their helper molecules—provides protection against many scourges of aging.
☑️ Don’t bother taking antioxidant supplements if you don’t have a medical indication
☑️ Invest in good food like fruits, vegetables, and berries instead
Is there evidence for blueberries and the like reducing radiation risks?
We will never see a randomized, double blind, placebo controlled clinical trial looking at reducing the effects of ionizing radiation in airplanes by eating antioxidant-rich blueberries. This is not outrageous. But here are some snippets from 5 studies in mainstream journals that I’ve cherrypicked, and that I think can be extrapolated harmlessly to some degree:
High dietary antioxidant intakes are associated with decreased DNA damage and chromosome translocation frequency in airline pilots.
Carotenoids are a diverse group of natural pigments and are present in many fruits and vegetables. Data from studies suggest that several carotenoids might provide a beneficial impact on reducing carcinogenesis. Dietary lycopene or β-carotene were associated with a decreased risk of each type of cancer that was reviewed.
Antioxidants taken orally prior to diagnostic radiation exposure can help prevent DNA injury.
In irradiated rats, treatments with blueberry extract restored liver pro-oxidant status, reduced cytokine levels, ameliorated histopathological parameters and reduced DNA damage.
Cancer cells avoid death by remodeling themselves,” Dr. Fang said. “Along with reducing cell proliferation, the blueberry extract also ‘tricks’ cancer cells into dying. So it inhibits the birth and promotes the death of cancer cells.
Take away
Recall that airport scanners are extremely safe. The amount of ionizing radiation we receive while flying has been shown to be fairly trivial in the grand scheme of things. Nonetheless it is gratuitous radiation, and so we might as well put in a little extra effort to combat the reactive oxygen species produced after long flights. But we should be doing this anyway on a daily basis in terms of combating the background radiation to which we are constantly exposed. Antioxidants in foods help.
Fruits and vegetables. Eat them. Berries are amazing, and I highly recommend them (along with every other wannabe health guru out there). I’ll splurge on blueberries after a flight, or especially with a radiological scan. I’m not too proud to admit my almost superstitious zeal. Frozen ones are fine and cost a lot less this time of year. Increasing foods rich in antioxidants is a good year round strategy. It can reduce our risks of cardiovascular disease, neurodegeneration, and cancer.
And if all this doesn’t make a huge difference after flying in particular, who cares? You’re hedging a low risk gamble in the stratosphere with something that is good for you anyway, and delicious.
And yes, I believe flight attendants could absolutely be handing out blueberries instead of pretzels. I don’t care if the airline adds $6 to my ticket price. They already added $50 for my luggage, right?
Master checklist
I hope you’ve enjoyed this three part series on infections, blood clots, and radiation exposure. For anyone who makes checklists before traveling, here are the ones I’ve come up with in this series. They are not as important as your checkbox for socks… which I often forget somehow. Unbelievable.
Take good care… and safe, happy travels!
☑️ Wear an N95/KN95 mask on the plane
☑️ Consider packing a decongestant
☑️ Move around on the plane
☑️ Stay hydrated
☑️ Avoid alcohol on the plane
☑️ Consider wearing compression stockings
☑️ Only if you are higher risk, consider a blood thinner with your doctor
☑️ When it comes to airport scanners and radiation risk - chillax
☑️ Don’t worry about the radiation received on a flight. Calculating your added cancer risk, both in terms of individual and cumulative flights, leads to numerical reassurance.
☑️ Don’t bother taking antioxidant supplements if you don’t have a medical indication
☑️ Invest in good food like fruits, vegetables, and berries instead
[END]
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