The radiation leaking from crippled nuclear power plants in Japan has unleashed fears on this side of the ocean. Despite assurances from experts that the amount of radiation reaching the U.S. is miniscule and harmless, many people here are worried that the fallout could pose a serious health threat.
And if William McBride's inbox is any indication, they're also wondering whether they should protect themselves by taking supplements or changing their diets. "I've been getting emails from friends asking me if they should take this or that," said McBride, professor of radiation oncology at the UCLA Jonsson Comprehensive Cancer Center. "It's all based on a fear of radiation."
McBride's response: Don't bother. There's no evidence, he says, that anything at a health food store or grocery store could really protect you from nuclear fallout. And in some cases, he warns, the remedies could be more dangerous than the radiation.
Many people have decided to hedge their bets against radiation anyway. Stores up and down the West Coast are running low on kelp supplements and other sources of iodine, a nutrient that can protect the thyroid from radiation poisoning. Many people are also hoping to get extra radiation protection from antioxidants, such as vitamin E, vitamin C or selenium, either from supplements or foods.
Health food proponents often repeat a claim — which apparently dates back to a 1980 book by a Japanese physician — that a macrobiotic diet of miso soup, brown rice and seaweed helped many survivors of the Hiroshima bombing avoid radiation sickness.
Cherie Calbom, a self-described celebrity nutritionist and author of "The Juice Lady's Turbo Diet," says she covers her bases by putting a drop of iodine into her morning green smoothie, which includes antioxidant-rich ingredients such as chard, spinach and lemon juice. In a recent blog post, she wrote that iodine and antioxidants could lower the risk of thyroid cancer and other cancers caused by radiation.
"People want to do something," said Calbom, who lives in Seattle. "There's a lot of stuff on the Internet that's scaring them."
McBride says he's all in favor of antioxidant-rich diets and the occasional bit of seaweed. But he sees no reason for anyone in the U.S. — or even Tokyo — to change their diets or take supplements to protect themselves from radiation.
He stressed that the amount of radiation reaching the shores of the U.S. from Japan was trivial compared with all of the natural radiation — from radon and cosmic rays, among other sources — that already surrounds us on a daily basis. "We live in a world that's radioactive," he said. "There's not enough [coming from Japan] to worry about."
Even if the radiation levels intensified, McBride wouldn't recommend nutritional defenses. High doses of iodine — delivered in potassium iodide pills — may be helpful in a nuclear emergency, he said, but it has to be used with care and supervision. "Many people are sensitive to iodine," he said, so taking it during a nonemergency "can do real harm without providing any benefits." The National Institutes of Health reports that people who are sensitive to iodine can suffer from swelling of the lips and face, bleeding and bruising, among other side effects.
Jeffrey Blumberg, professor of nutrition and director of the antioxidants research laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, agrees that the crisis in Japan is no reason to run to the health food store. In any case, he added, whether people are worried about nuclear fallout or other sources of high-energy radiation, such as X-rays or CT scans, tweaking their diets or their supplement regimens won't make them any safer.
Seaweed soups, kelp supplements and other low-level sources of iodine are generally considered safe, but McBride said they weren't going to pack enough punch to really protect anyone facing dangerous levels of radioactive iodine. A dose of potassium iodide contains about 100 mg of iodine. A capsule of Nature's Way Kelp offers 0.4 mg of iodine, about 250 times less.
Antioxidants do seem to be able to prevent DNA damage caused by radiation, Blumberg said. Radiation triggers the release of free radicals, trouble-making molecules that attack cells throughout the body. Because antioxidants can clean up free radicals, they can theoretically take away some of the sting of radiation.
A small 2009 study of pilots — a group of people who get a fair amount of cosmic radiation on the job — found that those who took antioxidant supplements had less DNA damage than those who didn't. And last week, researchers at the annual Society of Interventional Radiology meeting in Chicago presented a study suggesting that a proprietary antioxidant blend prevented DNA damage caused by CT scans.
But as Blumberg explained, damaged DNA is a fact of life that only rarely leads to cancer or any other disease. Nobody knows, he said, whether slightly reducing the amount of damage by taking antioxidants will make airline pilots or anyone else healthier. "There's no reason for anyone to take antioxidants before a CT scan," he added.
In an article published in the Journal of the National Cancer Institute in 2008, Blumberg and colleagues wrote that high doses of antioxidants could actually harm people receiving radiation therapy for cancer by protecting the tumor along with the healthy tissue.
Antioxidants are healthy and important nutrients, he said — but they aren't the antidote to nuclear fears.