Consuming sweetened drinks, especially of the diet soda or fizzy drink type, is tied to a higher risk for depression, while drinking coffee is linked to a slightly lower risk, according to new research due to be presented at a neurology conference in the US.
Study researcher Honglei Chen, of the National Institutes of Health in Research Triangle Park in North Carolina in the US, tells the press in a statement issued on Tuesday:
“Sweetened beverages, coffee and tea are commonly consumed worldwide and have important physical – and may have important mental – health consequences.”
The study will be presented at the 65th Annual Meeting of the American Academy of Neurology (AAN) that is due to take place in March in San Diego.
For the large study, AAN member Chen and colleagues evaluated beverage consumption from 1995 to 1996 among 263,925 people aged between 50 and 71. Beverages included sodas, tea, coffee, and sweetened fruit drinks.
About ten years later, the researchers asked the participants whether, at any time since the year 2000, they had received a diagnosis for depression. 11,311 of the participants reported they had received such a diagnosis.
When they compared the data on drinks consumption with the diagnosis for depression data, the researchers found that participants who drank more than four cups or cans of soda, either sugar-sweetened or diet, per day were 30% more likely to have received a diagnosis for depression than those who consumed none.
Those who drank four cans of fruit punch per day, either sugar-sweetened or diet, were about 38% more likely to develop depression than those who drank no sweetened drinks.
Consuming diet versions of soda, fruit punches and iced tea was associated with a greater risk for depression than consuming versions sweetened with regular sugar.
Coffee consumption, on the other hand, appeared to have a different effect. The researchers found participants who drank four cups of coffee per day were about 10% less likely to develop depression than those who drank none.
Chen says although the results still have to be confirmed by further studies, they suggest “cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk“.
In the meantime, Chen says people with depression should continue to follow the treatment prescribed by their doctor.
The study findings are yet to be published in a peer-reviewed journal, so have not been open to detailed independent scrutiny.
Experts reacting to this news appear somewhat sceptical of Chen’s conclusions, in that finding a link does not necessarily mean consuming sweetened drinks is the cause of depression. It could equally be suggesting that people predisposed to depression are more inclined to favour sweetened beverages.
Kenneth M. Heilman, professor of neurology at the University of Florida College of Medicine, told WebMD:
“There is much more evidence that people who are depressed crave sweet things than there is to suggest that sweetened beverages cause depression.”
Funds from the National Institutes of Health, the National Institute of Environmental Health Sciences and the National Cancer Institute helped pay for the study.
Previous studies have suggested a number of health problems are linked to consumption of sweetened drinks.
For instance, in 2010, researchers reported that reducing consumption of sugar-sweetened drinks could lower blood pressure, while another study reported that year found that regular consumption of sweetened beverages could raise insulin levels and thereby fuel the growth of pancreatic cancer cells.
And more recently, as more is discovered about how genetic and environmental factors act together in driving up the risk of obesity, Harvard researchers writing in a September 2012 issue of the New England Journal of Medicine, suggest people who regularly consume sugary drinks are genetically more susceptible to becoming obese or overweight.
Written by Catharine Paddock PhD