Findings add another reason to avoid sodas; fruit juice antioxidants may cancel out their sugars' effects
by Craig Weatherby
Surprisingly, before researchers at the University of Alabama decided to examine the possibility, no one had ever tested the brain effects of adding sugary liquid to the diet of mice.
As the scientists said, there is compelling evidence that drinking lots of sugar-sweetened drinks promotes obesity, which is a major risk factor for adult diabetes, which in turn is associated with greater risk of Alzheimer’s disease. In addition, high-fat diets promote underlying signs of Alzheimer’s in mice.
The Alabama team divided mice bred to develop an Alzheimer's-like condition in to two groups.
One group got sugar-sweetened water—containing 10 percent sucrose (cane sugar)—and the sugar-swilling rodents suffered greater losses in learning skills and memory compared with mice that drank plain water.
The “soda” group also underwent a two- to three-fold increase in the amount of beta-amyloid protein in their brains, which forms the “plaque” associated with Alzheimer’s.
The Alabamans also found a 2.5-fold increase in brain levels of apoE: a compound associated with higher levels of amyloid protein and plaque, which suggests that sugar promotes Alzheimer's-related plaque by increasing production of this undesirable chemical.
The authors came to an obvious conclusion: “These data underscore the potential role of dietary sugar in the pathogenesis of Alzheimer's disease, and suggest that controlling the consumption of sugar-sweetened beverages may be an effective way to curtail the risk of developing Alzheimer's disease.”
And as lead author Dongfeng Cao told Reuters Health, “Our findings are of tremendous importance given that the consumption of sugar-sweetened beverages has increased dramatically over the past decades and will most likely remain high in modern societies.”
Sugary water also made mice fat and diabetic, despite eating less food
After four months, the animals given sugar water weighed 17 percent more than the mice that drank plain water, despite being given the same amount of food to eat.
The sugar-drinking mice ate less food than those given plain water, they consumed 15 percent more daily calorie, and they got 43 percent of their total calories from the sugar water.
The sugar-swilling mice also developed early signs of diabetes and had very high levels of fat in their blood.
- Cao D, Lu H, Lewis TL, and Li L. Intake of Sucrose-sweetened Water Induces Insulin Resistance and Exacerbates Memory Deficits and Amyloidosis in a Transgenic Mouse Model of Alzheimer Disease. J Biol Chem. 2007 282: 36275-36282. First published on October 17, 2007; doi:10.1074/jbc.M703561200