Drinking soda — especially diet drinks — is linked to an increased risk of depression, a study finds.
However, drinks like coffee and tea — without artificial sweeteners — actually reduce the risk of depression slightly, the study also found.
The conclusions come from an analysis of 263,925 people aged 50 to 71-years-old who were followed over a decade.
Those who drank over four cans of soda per day were 30% more likely to be depressed than those who drank none.
On the other hand, those that drank four cups of coffee were 10% less likely to be experiencing depression than those that drank none.
The risk for soda appeared to be greater for those who drank the diet variety.
They study’s authors write:
“Unlike sugar-sweetened drinks, diet drinks often use artificial sweeteners such as aspartame and saccharin for the sweet taste and are calorie-free.
Our further analysis found that adding these artificial sweeteners to coffee or tea, but not adding sugar or honey, was associated with higher risk of depression.
Various effects of artificial sweeteners, including neurological effects, have been suspected.
For example, aspartame may modulate brain neurotransmitters such as dopamine and serotonin, although data have been controversial and inconsistent.”
Dr Honglei Chen, who led the study, said:
“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.
More research is needed to confirm these findings, and people with depression should continue to take depression medications prescribed by their doctors.”
The study does not rule out the possibility of reverse causation (that depression causes higher soda intake), they write:
“One possibility is that depressed individuals may crave sweet beverages, and one may speculate that this may occur even years before receiving a diagnosis of depression.”
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in the journal PLOS ONE (Guo et al., 2014).