in the US have found that mice given a sugar solution
as part of their daily diets showed increased signs of
developing Alzheimer's disease.
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
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
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
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,"
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,"
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
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