The first study discloses that excess sugar, particularly the added fructose in sugary drinks, might damage your brain. Researchers looked at data from the Framingham Heart Study (FHS) and found that people who drink sugary beverages frequently are more likely to have poorer memory, smaller overall brain volume, and a significantly smaller hippocampus—an area of the brain important for learning and memory.
As if that wasn’t bad enough, the second, a follow-up study, found that people who drank diet soda daily were almost three times as likely to develop stroke and dementia than hose who did not.
These findings, the researchers note, show a correlation but not cause-and-effect. Although experts warn against over-consuming either diet soda or sugary drinks, 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.
Not Much Upside
Senior author Sudha Seshadri, a professor of neurology at Boston University School of Medicine, said:
“These studies are not the be-all and end-all, but it’s strong data and a very strong suggestion. 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.”
Although the researchers took age, smoking, diet quality, and other factors into account, they could not completely control for preexisting conditions like diabetes, which may have developed over the course of the study and is a known risk factor for dementia.
Diabetics, as a group, drink more diet soda on average, as a way to limit their sugar consumption, and some of the correlation between diet soda intake and dementia may be due to diabetes, as well as other vascular risk factors. However, such preexisting conditions cannot wholly explain the new findings.
Dr. Ralph Sacco, neurology department chairman at the University of Miami, speaking to CTV News, said the findings are consistent with earlier studies suggesting links between artificially-sweetened drinks and dementia and stroke risks:
“I think, like everything, we need more studies to confirm whether the association is true and causal or whether the association is caused by something else.”
Stroke And Dementia
The second study, published in the journal Stroke, used data only from the older FHS Offspring cohort, specifically investigated whether participants had suffered a stroke or been diagnosed with dementia due to Alzheimer’s disease.
After measuring volunteers’ beverage intake at three points over seven years, the researchers 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. Here they found, surprisingly, no correlation between sugary beverage intake and stroke or dementia.
However, they found that people who drank at least one diet soda per day were almost three times as likely to develop stroke and dementia.
The Framingham Heart Study is supported by the National Heart, Lung, and Blood Institute and by grants from the National Institute on Aging and the National Institute of Neurological Disorders and Stroke.