New research suggests sugary, carbonated drinks may be linked to elevated levels of depression.
The study, published in the journal Scientific Reports, evaluated the effects of those drinks on more than 87,000 Korean subjects who reported symptoms of depression.
Study subjects were organized into five groups depending on the number of sugar-sweetened carbonated drinks they consumed in a week, between "almost never" or "five or more drinks."
The study found that the risk of depressive symptoms was proportional to the number of drinks consumed. The more drinks a subject had, the higher their risk of depressive symptoms.
The effects appeared to be the same between those with pre-diabetic risk and those with normal blood sugar — which suggests insulin resistance or blood sugar levels don't appear to play a part in determining risk for depression symptoms.
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But there are other possible mechanisms that would require further study, like the effects on the gut microbiome or the effects of chronic inflammation, which this research didn't account for.
The researchers warn the results also might not be equally applicable to other populations. Many Americans, for example, consume more sugar-sweetened carbonated drinks than the Korean population measured in the study. Older or younger people may experience different effects. And this study didn't look at the effects of diet drinks at all.
Still, other research has shown a link may exist. A study published in 2014 showed a "modest positive association" between consumption of sweetened drinks like soda and depression.