The findings, by the American Society for Biochemistry and Molecular Biology (ASBMB), could place more pressure on soft drinks manufacturers, who are already under attack for their role in the rising obesity epidemic. Although both obesity and diabetes have already been linked to the development of Alzheimer's disease, researchers Ling Li and her colleagues aimed to examine whether high sugar consumption in an otherwise normal diet would affect Alzheimer's progression. Using a genetic mouse model that develops Alzheimer's-like symptoms in adulthood, the scientists supplemented the balanced diet of half of the animals with 10 per cent sugar water. After 25 weeks, they found that the sugar-fed mice had gained around 17 per cent more weight than the controls, had higher cholesterol levels, and developed insulin resistance. Following memory skill and brain composition tests, the sugar-fed mice were also found to have worse learning and memory retention and their brains contained over twice as many amyloid plaque deposits, an anatomical hallmark of Alzheimer's. The researchers stated they "cannot be certain if the increased mental impairment resulted specifically from the higher sugar intake or higher calories in general". According to Liz Bastone of the British Soft Drinks Association, this is consistent with what has been previously suggested about the link between obesity and Alzheimer's. "The critical factor is the balance between calories in and calories out, rather than the source of the calories. That means that soft drinks, like other food and drink products, can be enjoyed as part of a balanced diet," she told FoodNavigator.com. However, the researchers said their findings "highlight the potential risk of sugary beverages". "The human equivalent of the mouse diet would be roughly five cans of soda per day, although since mice have a higher metabolism, it may actually take less sugar intake in humans," they said. Currently, about 12 million people in the US plus the EU suffer from Alzheimer's, with some estimates predicting this figure will have tripled by 2050. The direct and indirect cost of Alzheimer care is over $100 bn (€ 81 bn) in the US alone. The direct cost of Alzheimer care in the UK was estimated at £15 bn (€ 22 bn). Evidence has emerged over the last five years that many of the conditions that raise the risk for heart disease, such as obesity, uncontrolled diabetes and hypercholesterolemia, also increase the risk for Alzheimer's. A study published last year in the Journal of Alzheimer's Disease found a "strong correlation" between obesity and Alzheimer's. Scientists at Thomas Jefferson University in Philadelphia and Edith Cowan University in Joondalup, Western Australia, found that the fatter a person, the higher their blood levels of beta-amyloid, a sticky protein substance that builds up in the Alzheimer's brain. According to the researchers, beta-amyloid is thought to play a major role in destroying nerve cells and in cognitive and behavioral problems associated with the disease. The researchers claimed their study was one of the first attempts to try to find out on both the pathological and the molecular levels how obesity was increasing the risk of Alzheimer's.