diet soda linked to stroke and dementia

Many of us opt for artificially sweetened beverages over sugar-sweetened drinks, swayed by the belief that they are better for health.

A new study, however, suggests that this may not be the case.

Researchers found that adults who consumed at least one artificially sweetened drink per day were almost three times more likely to develop stroke or dementia compared with those who drank the beverages less than once weekly.

Matthew Pase, Ph.D., a study co-author from the Department of Neurology at the Boston University School of Medicine in Massachusetts, and his colleagues published their findings today in the journal Stroke.

As a result of the burgeoning war on sugar, more people are turning to artificially sweetened foods and drinks as “healthful” alternatives.

However, an increasing number of studies are finding that artificially sweetened products are far from innocent.

One study published last year, for example, associated aspartame – an artificial sweetener commonly found in diet soda – with weight gain in mice.

The new research suggests that the potential harms of artificial sweeteners may extend to the brain.

Read more: Artificial sweeteners may encourage fat production »

Alzheimer’s, stroke risks

The researchers came to their results by analyzing data from the Framingham Heart Study Offspring Cohort.

The data included 2,888 adults aged 45 and older as part of the stroke arm of the study as well as 1,484 adults aged 60 and older as a part of the dementia section of the research.

Over a period of seven years, study participants reported their dietary habits through regular completion of food frequency questionnaires. The researchers used this information to determine participants’ consumption of artificially sweetened beverages.

The team followed the subjects over the next 10 years to monitor the development of stroke and dementia.

The researchers identified 97 cases of stroke. Of these, 82 cases were ischemic stroke, which is a type of stroke caused by a blockage in a blood vessel that supplies blood to the brain.

A total of 81 cases of dementia were identified over the 10 years of follow-up. Of these cases, 63 were Alzheimer’s disease, the most common form of dementia.

Compared with adults who drank artificially sweetened beverages less than once per week, those who consumed these beverages at least once daily were found to be at three times greater risk of ischemic stroke and 2.9 times increased risk of Alzheimer’s disease.

These results remained after accounting for a number of influential factors, including participants’ age, sex, education, diabetes status, and presence of the ApoE gene, which is associated with greater Alzheimer’s risk.

The researchers found no association between the intake of sugar-sweetened drinks and the risk of stroke and dementia, although they caution that sugary beverages pose other harms to health.

“We recommend that people drink water on a regular basis instead of sugary or artificially sweetened beverages,” notes Pase.

Read more: Children consuming lots more artificial sweeteners »

Study limitations

While the current findings suggest a link between regular intake of artificially sweetened drinks and stroke and dementia, the researchers stress their study is purely observational, so no conclusions can be drawn.

Furthermore, the team points to the small number of study participants with stroke and dementia as a significant limitation.

"Even if someone is three times as likely to develop stroke or dementia, it is by no means a certain fate," says Pase. "In our study, 3 percent of the people had a new stroke and 5 percent developed dementia, so we're still talking about a small number of people developing either stroke or dementia."

However, in an editorial linked to the study, Rachel K. Johnson, professor of nutrition at the University of Vermont, says that we should be mindful about regular consumption of artificially sweetened drinks.

"We know that limiting added sugars is an important strategy to support good nutrition and healthy body weights, and until we know more, people should use artificially sweetened drinks cautiously,” said Johnson.

“They may have a role for people with diabetes and in weight loss, but we encourage people to drink water, low-fat milk, or other beverages without added sweeteners.”

Read more: Artificial sweeteners may not be sweet to obese people »