EATING fast food could contribute to the risk of developing Alzheimer's disease, a new Swedish study has found.

Researchers at the Karolinska Institute, a leading medical university in the Swedish capital Stockholm, fed mice a diet rich in fat, sugar and cholesterol for nine months and studied their behaviour.

"On examining the brains of these mice, we found a chemical change not unlike that found in the brains of Alzheimer's sufferers," said Susanne Akterin, who conducted the experiment for her doctoral thesis. The study detected increased levels of phosphate, which makes a sufferer's cells become tangled and eventually leads to their death. The team also found dietary cholesterol reduced the body's ability to produce a protein vital to memory storage.

The cause of the disease remains unknown, but previous studies indicate diet could be a factor. Alzheimer's is the most common form of dementia and there are believed to be more than 24 million sufferers worldwide, a figure set to double every 20 years, the World Health Organisation says.