Why is soda bad for you? The list is long. It has no nutritional value whatsoever, it rots our teeth, it isn’t actually hydrating, and it has been linked to obesity, high blood sugar, osteoporosis, and a wide range of other health problems. And now there’s more.
New research published in Alzheimer’s & Dementia suggests that fructose in sugary beverages might damage the brain. A team from Boston University, using data from the Framingham Heart Study (FHS), found that people who regularly drink sugary drinks are more likely to have poorer memory, smaller overall brain volume, and a significantly smaller hippocampus—the part of the brain important for learning and memory. (Here are five strategies to improve your memory.) A second study, published in the journal Stroke, found that people who drank diet soda daily were almost three times as likely to develop stroke and dementia when compared to those who didn’t.
The first study involved examination of data, including magnetic resonance imaging (MRI) scans and cognitive testing results, from around 4,000 people enrolled in the Framingham Heart Study’s Offspring and Third-Generation cohorts. A “high intake” group was established: people who consumed more than two sugary drinks a day of any type, including fruit juice and other soft drinks, or more than three per week of soda alone. In that group, researchers identified multiple signs of accelerated brain aging, including smaller overall brain volume, poorer episodic memory, and a shrunken hippocampus, all risk factors for early-stage Alzheimer’s disease. They also found that higher intake of diet drinks—at least one per day—was associated with smaller brain volume.
The second study used data only from the older Offspring cohort and focused on whether participants had suffered a stroke or been diagnosed with dementia due to Alzheimer’s disease. Researcher measured volunteers’ beverage intake at three points over seven years, then monitored the volunteers for 10 years, looking for evidence of stroke in 2,888 people over age 45, and dementia in 1,484 participants over age 60. While they found no correlation between sugary beverage intake and stroke or dementia, they found that people who drank at least one diet soda per day were almost three times as likely to develop stroke and dementia.
It’s important to note that the findings of both studies demonstrate correlation but not cause-and-effect. The advice from researchers is to avoid over-consuming either diet soda or sugary drinks, but more research is needed to determine how—or if—these drinks actually damage the brain, and how much damage may be caused by underlying vascular disease or diabetes. “These studies are not the be-all and end-all, but it’s strong data and a very strong suggestion,” says Boston University School of Medicine professor of neurology Sudha Seshadri, MD, as reported by Science Daily. “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.”
Will this latest research will encourage you to quit sugary drinks? If you’re still not convinced, here are more reasons to avoid all soda.