Diet soda's bad reputation is about to get worse: two new studies say that the faux sugary substance may actually increase your risk of dementia and stroke.
The first study analyzed brain scans and cognitive tests from about 4,000 people who consumed more than two sugary drinks a day, like soft drinks or juice, or three sodas per week. They found that these sweet beverage drinkers had risk factors for early-stage Alzheimer’s disease including prematurely aged brains, smaller overall brain volume, poor episodic memory and a smaller hippocampus. Those who drank at least one diet soda a day had smaller brain volume, according to an article by Boston University.
Then in a second study, researchers looked to see whether beverage consumption could be linked to dementia or stroke. Looking at 2,888 people older than 45 years old for incidents of stroke and 1,484 people 60 and older for evidence of dementia, the team recorded beverage consumption at three different points in time over the course of seven years. They found that participants who drank one diet soda per day were about three times as likely to have a stroke or dementia. Both studies show correlation, but not a cause-and-effect relationship.
Age, smoking, diet quality, and other factors were taken into account, but preexisting conditions such as diabetes could not be controlled for. Researchers used data from the Framingham Heart Study, a project aimed to identify factors that cause cardiovascular disease.
"These studies are not the be-all and end-all, but it's strong data and a very strong suggestion," says Sudha Seshadri, professor of neurology at Boston University School of Medicine (MED) and faculty member at BU's Alzheimer's Disease Center, in a statement. Seshadri is a co-author on both papers. "It looks like there is not very much of an upside to having sugary drinks, and substituting the sugar with artificial sweeteners doesn't seem to help."
Soda consumption is declining in the United States as consumers become more health conscious. Over the years, numerous studies have provided plenty of reasons to eliminate the sugary substances as soft drinks have been linked to heart disease risk, diabetes and obesity.
"Maybe good old-fashioned water is something we need to get used to," says Seshadri.