The best bet seems to be a low-calorie, low-fat diet with plenty of vegetables, fruits and fish. Now a new study suggests that high protein diets may present an Alzheimer's threat. This news comes from researchers in Britain, Canada and the United States who tested four different diets on transgenic mice with a mutant form of the human amyloid precursor protein (APP), which the body uses to generate amyloid plaques typical of Alzheimer's. The mice received (1) a standard mouse diet, (2) a high protein/low carb diet, (3) a high-fat/low carb diet or (4) a high-carb/low fat option. Unexpectedly, the brains of the mice on the high protein/low carb diet were five percent lighter than those of all the other mice - a finding that may mean that brain cells are more vulnerable to the plaque seen with Alzheimer's in humans. To find out for sure whether a high protein/low carb diet influences Alzheimer's risk in humans we would need a large, randomized, double-blind trial. That isn't on the drawing boards. The mouse diet study was published online on October 21, 2009 in the open access journal Molecular Neurodegeneration.