A Toronto doctor and coroner is promoting the notion of a link between Alzheimer's disease and the types of meat we eat.

"There seems to me to be a strong correlation between the processing of meat and the rates of Alzheimer's," Dr. Murray Waldman told CTV News.

It's not a theory borne of laboratory experimentation, but from looking at the big picture. Rates of Alzheimer's are lower in countries that don't consume much meat and higher in ones where vast quantities of meat are mixed together to make hamburgers, salamis and sausages.

That is an efficient way of transmitting a still-unidentified infectious agents like prions, he says.

Waldman, who has written a book entitled Dying for a Hamburger, thinks prions might be linked to Alzheimer's.

"The major characteristic of all prion diseases is dementia. And that is the major characteristic of Alzheimer's," he said.

The University of Toronto's Dr. Neil Cashman bristles at the theory. "It most certainly is not a prion disease," he says of Alzheimer's.

He doesn't believe Waldman has made a causal link between Alzheimer's and the meat-packing industry.

A meat industry spokesperson says the book and the theory are not credible.

"My reaction is that Canadian consumers of hamburger and beef should not be concerned," says James Laws of the Canadian Meat Council.

Although the theory isn't proven, it will be discussed at two major scientific conferences in the coming months.

"I think it points the way to further research," Waldman said.

Waldman is hoping to inspire scientists to keep looking for a reason why so many end their lives with healthy bodies but diseased brains.

With a report from CTV's Avis Favaro