Scientists studying Alzheimer's disease (AD) in mice found that a high protein diet led them to develop smaller brains.
The research team from the US, Canada and the UK were focusing on triggers for brain plaque formation and monitored the effects of four different food regimes on rodents which were genetically modified to develop a severe form of early-onset Alzheimer's.
Previous studies into AD pointed towards a low-calorie, low-fat diet rich in vegetables, fruit and fish, possibly delaying its onset or slowing its progression.
In the new study, the mice were fed either a regular diet; a high fat/low carbohydrate diet; a high protein/low carb version or a high carb/low fat option.
The researchers then looked at the brain and body weight of the mice, as well as plaque build up and differences in the structure of several brain regions that are involved in the memory defect underlying AD.
Unexpectedly, mice fed the high protein/low carb diet were found to have brains five per cent lighter than the others.
Regions of their hippocampus, a major component of the brain, were less developed than in their counterparts.
The researchers will investigate the tentative theory that a high protein diet may leave neurones more vulnerable to AD plaque.
The study will now be expanded to look at mice, which were not genetically altered, and investigate the implications for humans.
The study has been published in BioMed Central's open access journal Molecular Neurodegeneration.