Radiation emissions from mobile phones could place users at risk of brain conditions including Alzheimer's Disease, according to new reports.
Researchers in Sweden have found that just two minutes' exposure to energy waves from a handset can disable a defence mechanism in the body designed to prevent harmful proteins and toxins in the blood from entering the brain.
In what is the latest in a series of mobile phone health scares, once the proteins enter brain tissue there is a higher risk of brain and nerve diseases such as Alzheimer's, Parkinson's and multiple sclerosis developing.
The study by scientists at the University of Lund, near Malmo, exposed rats to microwave pulses similar to the emissions from a mobile phone to calculate the effect on the body's blood-brain barrier, the Daily Mail reports.
Within two minutes of exposure, the rats' brain tissue was found to be opened up to proteins and toxins contained in the blood after the defence mechanism was disabled.
Professor Leif Salford, the neurologist who carried out the study, told the paper: "We saw the opening of the blood-brain barrier even after a short exposure to radiation at the same level as mobile phones.
"We are not sure yet whether this is a harmful effect, but it seems that molecules such as proteins and toxins can pass out of the blood while the phone is switched on and cross into the brain."
The research could also cast doubt on current safety guidelines drawn up by the World Health Organisation after it was found the blood-brain barrier can be breached without the mobile phone emissions heating the rats' heads.
'No firm evidence'
Manufacturers are restricted in the strength of microwaves they can use so that they do not exceed levels which would excessively heat users' heads, but the new study indicates damage could occur within current norms.
Mobile phone makers insist radiation amounts are within safety guidelines and a report by the New Scientist earlier this year dismissed the notion that these microwaves could "cook" the brain.
"A mild bout of exercise will heat your head more than the puny microwaves that the devices emit," said the article.
Last month, an all-party committee of MPs also agreed there was no firm evidence to prove there was a health risk from mobile phones.