People who reported regularly drinking soft drinks and other sugary beverages were more likely to suffer from memory problems, according to new research by Boston University scientists, who encouraged soda lovers to switch to water as they await more data on the issue.
The findings, reported in a pair of recent studies, raised questions about both sugary and artificially sweetened beverages.
Research participants who said they drank a lot of diet soda appeared to be more likely to suffer strokes and dementia, according to the study.
Matthew Pase, a fellow in neurology at BU’s School of Medicine and an author of the two recent papers, cautioned that the results do not prove that the beverages cause the outcomes. But Pase said they make a case for additional research — and for people to watch what they drink.
“We didn’t see any benefits to drinking diet soda, and we didn’t see any benefits to drinking sugary beverages,” he said. “And they don’t have any nutritional value, so it’s safe to say that water is the safest beverage.”
The findings appeared in the journal Alzheimer’s & Dementia and the journal Stroke and used data from the Framingham Heart Study, the multigenerational project that focuses on health issues among thousands of residents of the town.
Researchers performed MRIs and cognitive tests on about 4,000 people. The researchers then undertook 10 years of monitoring for strokes in 2,888 people who were 45 and over. They also watched 1,484 people age 60 and older for dementia.
They found that people who reported drinking more juices and sugar-sweetened soda were more likely to have poorer memory and smaller brain volumes.
People who said they drank diet soda every day were three times as likely to develop stroke and dementia, including Alzheimer’s disease, according to researchers, who said they did not believe cardiovascular disease, diabetes, and high blood pressure explained the findings.
The study removed diabetics, many of whom said they drank diet soda, from the inquiry because that disease is associated with the risk of dementia.
Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital, who was not involved in the study, said the research on sugar is “very plausible,” and fits in with research on animals.
However, she said that the findings on diet soda should be taken with caution.
“It’s really unclear at this point that this is a cause-and-effect relationship, but more research is clearly needed,” she said. “I think there’s enough concern raised that the public may want to minimize the use of artificial sweeteners.”
Andy Rosen can be reached at andrew.rosen@globe.com. Follow him on Twitter at @andyrosen.