A report in a British newspaper suggests there may be a link.
The frightening possibility of Alzheimer's disease being induced by suncream is being investigated by academics.
Millions of British holidaymakers use block to protect their skin from the sun every year.
Now the University of Ulster says two of its experts have been awarded £350,000 by the European Union to explore the possible links between the suncream and the brain disease.
They are leading a groundbreaking three-year research project into whether human engineered nanoparticles, such as those found in sunscreen, can induce neurodegenerative diseases such as Alzheimer's and Parkinson's.
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Professor Vyvyan Howard, a pathologist and toxicologist, and Dr Christian Holster, an expert in Alzheimer's, are conducting the latest research as part of a worldwide project called NeuroNano.
The University of Ulster experts will be specifically looking at nanoparticles present in chemicals found in sunscreens and an additive in some diesel fuels - titanium dioxide and cerium oxide - and their connection to Alzheimer's and Parkinson's diseases.
Professor Howard said: 'There is now firm evidence that some engineered nanoparticles entering intravenously or via lungs can reach the brains of small animals.
'Indeed they lodge in almost all parts of the brain and there are no efficient clearance mechanisms to remove them once there.'
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'It has recently been discovered that nanoparticles can have highly significant impacts on the rate of misfolding of key proteins associated with neurodegenerative diseases like Alzheimer's and Parkinson's disease.
'The brain itself is a very special organ. It cannot repair by replacing nerve cells, the ones you get at birth have to last all your life, which makes them peculiarly vulnerable to long term low dose toxicity.'
The brain had built up some protective mechanisms but a major worry was that nanoparticles seemed to be able to circumvent them, he said.
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'The risk that engineered nanoparticles could introduce unforeseen hazards to human health is now also a matter of growing concern in many regulatory bodies, governments and industry,' said the professor.
There's more at the link.
That's a scary thought! I don't know how many millions - billions? - of tubes and bottles of sunscreen are used annually, but it's got to be a huge number. I've gone through three or four tubes in a week to protect my face, neck, arms and legs while attending outdoor courses. To be told now that some of the hi-tech sunscreens may have unforeseen and unwanted side effects . . . well, it's a bit late, isn't it? If this is proved to be true, why didn't the manufacturers test for such side effects before marketing their products?