Sugary drinks may impact memory and diet alternatives could cause dementia

By Kate Bass, B.Sc.Apr 21 2017

New research, published in both Alzheimer's & Dementia and Stroke indicate that drinking sugary drinks regularly may lead to a reduction in the size of the brain and poorer memory.

Credit: Thanamat Somwan / Shutterstock.com

Including high levels of sugar in the diet has long been known to be bad for health, having a range of adverse effects on the body, including metabolic dysfunction, liver damage and high blood pressure. Many people choose diet soft drinks in the belief that they are a healthier alternative to sugary drinks, but these too have been associated with an increase in metabolic and cardiovascular risk effects that can increase the risk of cerebrovascular disease and dementia.

Data collected from around 4,000 people aged 30 years or older who participated in the Framingham Heart Study (FHS) have been analysed to investigate how the intake of sweet drinks impacts brain volume, cognitive function and memory. Almost 3,000 people aged over 45 years were subsequently monitored for the development of stroke, and nearly 1,500 people who were 60 years old or more were assessed for signs of dementia.

The results showed that people who frequently drink sugary beverages, such as sodas and fruit juices are more likely to have poorer memory and a smaller brain size. In particular, the volume of the hippocampal area of the brain (which is important for memory) was reduced by excessive consumption of sugary drinks.

In addition, it was found that the risk of developing stroke and dementia was three times higher among people who drank diet soda daily than among those who did not drink diet soda.

Dr Matthew Pase, author of the research paper and fellow in the Department of Neurology at Boston University School of Medicine, explained:

“Our findings indicate an association between higher sugary beverage intake and brain atrophy, including lower brain volume and poorer memory...We also found that people drinking diet soda daily were almost three times as likely to develop stroke and dementia. This included a higher risk of ischemic stroke, where blood vessels in the brain become obstructed and Alzheimer's disease dementia, the most common form of dementia”.

The differences between patients who did and did not drink sugary or diet beverages could not be entirely explained by pre-existing cardiovascular disease, diabetes and high blood pressure. People who frequently consumed diet soda were more likely to have diabetes, which may increase the risk of dementia, but even when people with diabetes were excluded from the analysis diet soda consumption was still associated with an increased risk of developing dementia.

The authors highlight that these are preliminary findings and that further research is required to confirm whether high sugar intake or the artificial sweeteners added to diet drinks can have adverse effects on the brain.