The radiation emitted after just 50 minutes on a mobile phone increases the activity in brain cells, according to a new government-funded study.
The effects of that brain activity are not known, said the researchers, who called for more study.
Phones that were turned off did not create the same brain activity.
The small study, published in the Journal of American Medical Association, is the first to look specifically at how electromagnetic radiation from cell phones affects glucose metabolism, a normal function, in the brain.
“When glucose metabolism goes up, it activates cells. The findings are an indication that exposure to cell phones activate the brain much more easily than we previously thought,” said Dr. Nora Volkow, National Institutes of Health neuroscientist and lead study author.
Brain activity means that the cells are using glucose to create energy. The brain normally produces the amount of glucose it needs to function properly. But these new findings don’t tell us whether activating the cells artificially, in this case by cell phone radiation, will have a negative effect on health. Volkow says she simply doesn’t know and calls for further investigation.
The CITA, the wireless industry trade group, noted that no research has found cell phones to be a danger to health.
“The peer-reviewed scientific evidence has overwhelmingly indicated that wireless devices, within the limits established by the FCC, do not pose a public health risk or cause any adverse health effects,” said a statement from John Walls, the group’s vice president for public affairs. “In May 2010, the Interphone project, coordinated by the International Agency for Research on Cancer, which was the largest study of cell phone use and brain tumors ever undertaken and included substantial numbers of subjects using cell phones for ten years or longer, found that ‘overall, no increase in risk was observed with the use of mobile phones.’ ”
The study was praised as offering “an important insight into potential effects of cell phone radiation on the human brain” by Renee Sharp, director of the Environmental Working Group California office. “It joins the growing list of studies that have raised concerns about cell phone use and the brain.”
Researchers measured brain activity of 47 healthy adults — a small but scientifically valid size group for this type of study — while using a mobile device.
The levels were tested when the phone was in use (transmitting radiation) against the head and when against the head but in the off position. Compared with subjects whose phones were turned off, the group whose phones were on had “significantly higher” brain activity in the area closest to the telephone antenna.
The findings of the study, which examined the subjects during just one 50-minute exposure, raise a key question, the researchers said: What, if any, are the long-term consequences of repeated increased brain activity due to exposure to cell phone radiation?
“We need to rule out that there is a not long-lasting effect in healthy people,” Volkow said. “We don’t know what repeated exposure and artificial activation of the glucose will have on the brain.”
With nearly 300 million cell phones in use in the United States, some experts say the concern lies with not only with the long-term impact on healthy individuals but in consumers with unhealthy cells as well.