There is a laboratory mouse strain which has been genetically engineered to develop Alzheimer's Disease. Not nice for the mouse, but very useful for research purposes. If you have a look at this abstract, it suggests that limiting calorie intake completely protects against Alzheimer's in this strain of mouse. So why does Alzheimer's still progress in humans, even when weight maintenance becomes very difficult due to the effects of the disease?
Well, the abstract is somewhat disingenuous. It is spectacularly silent about the type of calorie restriction used. Luckily the full paper is available as a pdf at the click of a link. Be warned though, this paper is about as readable as a telephone directory, in the dark, but not as well written. You have to read the abstract, the introduction, the materials and methods until finally you get to the results section. Then you find the best kept secret so far. It's on line three of the results.
OK, yes these animals were calorie restricted, but the ONLY calories removed were carbohydrate.
The discussion actually uses the C word quite a lot. That is, it mentions carbohydrate restriction rather than calorie restriction. But the final paragraph, the sum it all up paragraph, the "this is what we found" paragraph, drops right back to calorie restriction.
Can you imagine the outcry if this group had come up with the headline "Atkins type diet provides 100% protection against Alzheimer's disease in highly susceptible mouse model"? You would actually have heard the "pop" as their funding evaporated. Anyway, it was only mice.
What about humans? No one has done the study yet, though one is planned by the group that did the Parkinson's work I mentioned yesterday. What has already been done is the flip side. That is, increasing the carbohydrate intake of nursing home patients with Alzheimer's disease. This was done to try to limit their weight loss. Adding extra carbohydrate resulted in "increased carbohydrate preference, poorer memory and increased aberrant motor behavior".
And it made them fatter too.