Drinking sugary or diet beverages takes severe toll on brain, studies find

BOSTON — Water is looking better and better by the study. Research from two studies out of Boston University found the brain takes a beating from drinks loaded with sugar, as well as from diet beverages made with artificial sweeteners.

The team found that people who drink at least two sugary drinks a day are more likely to suffer from several brain deficiencies and face a higher risk of developing Alzheimer’s disease. In another study, they determined people who drink one serving of an artificially sweetened beverage every day are at serious risk of suffering from dementia or a stroke.

In the first study, researchers looked at data from 4,000 people enrolled in the Framingham Heart Study’s offspring and third-generation cohorts. Participants either drank at least two sugary drinks of any kind daily, or more than three per week of soda alone. The researchers found those who drank two high-sugar beverages each day were more likely to show “multiple signs of accelerated brain aging, including smaller overall brain volume, poorer episodic memory, and a shrunken hippocampus.”

Each of the results are risk factors for early-stage Alzheimer’s.

That study also found participants who drank at least one diet soda per day were more likely to have smaller brain volume.

Meanwhile, in the second study, researchers looked at data only from the offspring cohort of the Framingham Heart Study. The team examined 2,888 people at least 45 years old and recorded their beverage consumption at three points over seven years, then monitored them for another 10 years, specifically looking for evidence of a stroke. They performed the same analysis on 1,484 people at least 60 years old, but monitored for signs of dementia.

The researchers found participants who consumed at least one diet beverage a day were almost three times as likely to suffer a stroke or from dementia.

There was no correlation found between sugary drinks and stroke or dementia.

“These studies are not the be-all and end-all, but it’s strong data and a very strong suggestion,” says Sudha Seshadri, a professor of neurology at Boston University School of Medicine and a faculty member at BU’s Alzheimer’s Disease Center, in a university news release. “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.”

“Maybe good old-fashioned water is something we need to get used to,” adds Seshadri, who was a senior author on both papers.

Though some factors like age, diet, and tobacco use were factored into the results, the researchers could not control for preexisting conditions like diabetes, who are linked to dementia. Because diabetics are more prone to drinking sugar-free beverages, it’s possible, the team concedes, that diabetes could be a factor in the dementia study.

The cause-and-effect of artificial sweeteners being linked to the conditions were not determined, and the various types of sweeteners were not weighted in the studies.

“Our study shows a need to put more research into this area given how often people drink artificially-sweetened beverages,” says Matthew Pase, Ph.D., a senior fellow in the department of neurology at Boston University School of Medicine, Swinburne University of Technology in Melbourne, Australia, and the Framingham Heart Study. “Although we did not find an association between stroke or dementia and the consumption of sugary drinks, this certainly does not mean they are a healthy option. We recommend that people drink water on a regular basis instead of sugary or artificially sweetened beverages.”

Pase was the lead author on both studies.

The first study was published in March in the journal Alzheimer’s & Dementia. The second study was published this week in the journal Stroke.