(NaturalNews) Research on birds living near the Chernobyl nuclear disaster area adds more proof that antioxidants are able to protect the body from radiation damage. The study was published in the journal Functional Ecology on April 24.
The meltdown, explosion and fire at the nuclear power plant in Chernobyl, Ukraine on April 26, 1986 was, at the time, the worst civilian nuclear disaster the world had ever seen (today, scientists are split over whether the Chernobyl or Fukushima disaster was worse). The disaster widely contaminated the surrounding area with radiation, leading the Soviet government to permanently evacuate a three-kilometer area around the power plant.
The negative effects of the ongoing radioactivity in the region have been well documented, including changes in abundance, distribution, life history and mutation rates of many species. Birds in the area have smaller than usual brains and are more prone to cataracts, and radiation appears to be hampering the normal activity of decomposers such as insects and microbes.
But the absence of humans has also led to increase in biological diversity, with many rare plants and birds returning to the region, and wolves and boars even seen roaming the streets of an abandoned town.
Adaptation and antioxidants
The new study sought to determine whether any species of bird had been able to adapt to the elevated radiation levels in the Chernobyl exclusion zone. Laboratory studies have shown that over time, many organisms are able to adapt to low doses of radiation, making themselves less susceptible to damage caused by later, higher doses.
Much of the damage from radiation exposure occurs because ionizing radiation leads to the production of free radicals, which in turn damage (oxidize) cells and DNA inside the body. The presence of antioxidants inside the body, however, can neutralize free radicals before they are able to do damage.
In order to see whether wild birds were able to boost antioxidant levels to decrease radiation damage, the researchers captured 152 birds from 16 species at eight sites in and around the Chernobyl exclusion zone. They took blood and feathers samples from each bird and then released them, and also measured the background radiation levels at each site. Blood samples were tested for DNA damage, oxidative stress and levels of the key antioxidant glutathione. Feathers samples were tested for levels of the melanin pigments pheomelanin and eumelanin.
The body needs much higher levels of antioxidants to produce pheomelanin than it does to produce eumelanin.
Antioxidant-rich blood is protected
The researchers found that birds in higher radiation areas actually had higher levels of antioxidants (along with less DNA damage and less oxidative stress) than birds in lower radiation areas. This suggests that the higher radiation levels had caused the birds' bodies to better adapt by increasing antioxidant levels and thereby better protecting them from radiation.
The researchers also found that two species of birds, , great tits (Parus major) and barn swallows (Hirundo rustica), actually did worse in high radiation areas. Notably, these were the species with higher levels of pheomelanin in their feathers. This suggests that because the birds needed more antioxidants to make their feather pigments, they had less available to protect their bodies from the damaging effects of radiation.
The study does not mean that radiation exposure is a good thing, the authors cautioned.
"The effects of radiation at Chernobyl on populations of organisms, and for birds in particular, have been negative overall," they wrote.
What it does show is that the body seeks to protect itself from radiation - and antioxidants are one of the main tools it uses to do so.