Regular Consumption of Sugary Beverages Affects Brain
Researchers using data from the Framingham Heart Study (FHS), a joint project of the National Heart, Lung and Blood Institute and Boston University, have shown that people who more frequently consume sugary beverages such as sodas and fruit juices are more likely to have poorer episodic memory, smaller hippocampal and total brain volumes. The authors have also found that people who drank diet soda daily were 3 times as likely to develop stroke and dementia when compared to those who did not consume diet soda.
According to Pase et al , regular consumption of sodas, fruit juices and artificially sweetened sodas affects the brain. Image credit: Bruno Glaetsch.
Excess sugar is known to have adverse effects on health. Diet soft drinks are often touted as a healthier alternative to regular soda.
However, both sugar and artificially-sweetened beverage consumption has been linked to cardiometabolic risk factors, which increases the risk of cerebrovascular disease and dementia.
To measure the relationship between beverage intake and brain volumes as well as thinking and memory, Boston University School of Medicine researcher Matthew Pase and co-authors examined more than 4,200 participants over the age of 30 from the community-based FHS.
“We examined the cross-sectional association of sugary beverage consumption with neuropsychological and magnetic resonance imaging markers of preclinical Alzheimer’s disease and vascular brain injury in the community-based FHS,” the authors explained.
“Intake of sugary beverages was estimated using a food frequency questionnaire.”
“Relative to consuming less than one sugary beverage per day, higher intake of sugary beverages was associated with lower total brain volume, and poorer performance on tests of episodic memory,” they said.
“Daily fruit juice intake was associated with lower total brain volume, hippocampal volume, and poorer episodic memory.”
The team then monitored the FHS Offspring Cohort of 2,888 people (age 45 and over) for the development of a stroke and 1,484 participants (age 60 and older) for dementia for 10 years.
At the end of the 10-year follow-up period, the researchers noted 97 cases (3%) of stroke, 82 of which were ischemic (caused by blockage of blood vessels), and 81 (5%) cases of dementia, 63 of which were diagnosed as Alzheimer’s disease.
“We found that people drinking diet soda daily were almost three times as likely to develop stroke and dementia,” said Dr. Pase, who is also an investigator at the FHS.
“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.”
Preexisting conditions such as cardiovascular disease, diabetes and high blood pressure did not completely explain the findings.
For example, people who more frequently consumed diet soda were also more likely to be diabetic, which is thought to increase the risk of dementia. However, even after excluding diabetics from the study, diet soda consumption was still associated with the risk of dementia.
Although Dr. Pase and his colleagues suggest that people should be cautious about regularly consuming either diet sodas or sugary beverages, it is premature to say their observations represent cause and effect.
Future studies are needed to test whether giving people artificial sweeteners causes adverse effects on the brain.
“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. 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,” said Dr. Rachel K. Johnson, past chair of the American Heart Association’s Nutrition Committee and professor of nutrition at the University of Vermont.
The team’s findings are published in two papers in the journal Alzheimer’s & Dementia and the journal Stroke .