Drinking sugary or sweetened soft drinks is associated with an increased incidence of depression - with those consuming diet versions at the highest risk – while drinking coffee may be linked to a reduction in risk, say the US-based researchers.
The study, which is released today and is also due to be presented at the American Academy of Neurology's 65th Annual Meeting in San Diego, USA, followed more than 250,000 people for a decade.
Led by Dr Honglei Chen from the US the National Institutes of Health (NIH), the researchers found people who drank more than four cans of soda per day of soda were 30% more likely to develop depression than those who drank no soda, while people who drank four cups of coffee per day were around 10% less likely to develop depression than those who drank no coffee.
Those who drank diet versions of soda, iced tea, or other sweetened beverages including fruit punches were found to be at a higher risk of developing depression than people who drank ‘regular’ versions of the drink, said the research team.
"Sweetened beverages, coffee and tea are commonly consumed worldwide and have important physical—and may have important mental—health consequences," said Chen.
"Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk," said Chen.
Commenting on the study, the British Soft Drinks Association said that because the study is not yet published in its full form, it is not possible to examine the claims made “to see if the study really bears them out.”
Chen said while the findings are preliminary, and the underlying biological mechanisms are not yet known, “they are consistent with a small but growing body of evidence suggesting that artificially sweetened beverages may be associated with poor health.”