Mice who were given a sugar solution as part of their daily diet showed increased signs of developing Alzheimer's disease.
After 25 weeks, the sugar-fed mice had worse learning and memory retention, and their brains contained over twice as many amyloid plaque deposits. Amyloid plaque is a symptom of Alzheimer's.
It is unknown whether the symptoms were caused by a high-sugar diet specifically, or by a high-calorie diet in general. Obesity and diabetes have both already been linked to Alzheimer's disease.
* FoodNavigator.com December 10, 2007