Human bodies adapt to radiation exposure

A study on heart surgeons hints that regular exposure to low-dose radiation has prompted cellular changes that may protect our bodies from harm.

Got radiation on the mind? Well, for starters, in Mineral, Virgina – just a few miles from the epicenter of Tuesday’s quake – two nuclear reactors at the North Anna Power Station automatically shut down when the plant lost power from the electricity grid.

Now, a study on hospital workers routinely exposed to ‘safe’ levels of X-rays show that humans might actually adapt to withstand radiation exposure.

As in… there were changes at the cellular level that might represent the body’s way of protecting itself from ionizing radiation. What?

A team led by Gian Russo of the National Research Council in Italy took blood samples from 10 healthy cardiologists who are exposed to 4 millisieverts of radiation per year from heart operations using X-ray guided catheters.

These levels are up to 3 times higher per year than those experienced by radiologists. That’s slightly above average natural levels but well within the federal ‘safe’ limit of 50 millisieverts a year, New Scientist reports.

Here’s what they found:

  • The blood contained levels of hydrogen peroxide (a marker of cell damage) that are 3 times higher than expected.
  • BUT white blood cells in the samples also showed a marker that suggested they were more susceptible to death – which could indicate the body’s efficient removal of cells damaged by radiation.
  • AND the blood also contained twice the normal level of glutathione, an antioxidant that protects cells against damage.

In a news release [pdf], Russo says the results provide the first evidence that ‘safe’ radiation levels can induce profound biochemical and cellular changes – but it’s unclear whether those changes are damaging or beneficial.

However, according to cardiologist Tommaso Gori at the University Medical Center Mainz in Germany, boosted antioxidant levels are known to offer a degree of protection against heart attack in some individuals. "What doesn't kill you makes you stronger," he says. "That might be the case with low-dose radiation."

The study was published in European Heart Journal this week.

Image by microwavedboy via Flickr

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