First the good news: Of all the beverages studied in this National Institutes of Health (NIH) analysis, only coffee, 4 cups a day, is associated with a lower risk of depression–9% lower compared to other beverages.
And now the bad, perhaps even ugly, news: Artificially sweetened beverages, such as sodas, iced tea and fruit drinks, are more strongly associated with depression risk than are sugar-sweetened drinks.
Hongei Chen, MD, PhD, of the NIH and his research team followed 263,923 adults ages 50-70 for a decade, at the end of which 11,311 reported having been diagnosed with depression between 2000 and 2006.
Study participants regularly consuming 4 artificially sweetened soft drinks daily were at a 31% risk of developing depression; those consuming 4 sugar-sweetened soft drinks were at 22% risk.
Scientists found a similar correlation to risk with iced tea: Diet tea drinkers were at a 25% higher risk of developing depression; sugar-sweetened tea drinkers at a slightly lower risk.
Similarly, drinking 4 or more servings of fruit punch resulted in a 38% overall increase in risk with the risk slightly lower for sugar-sweetened punch.
Compared to those drinking no fruit punch, both groups regularly consuming fruit punch were at a 51% greater depression risk.
Robin Kanerek, PhD, interim dean of the Friedman School and John Wade Professor of Psychology at Tufts, sounds a cautionary note:
“For example, were there any other significant relations between depression and other variables—such as body weight, other illnesses, exercise, etc.?
“It is also possible that individuals who have a predisposition toward depression are more likely to consume sweetened beverages than individuals without such a predisposition.
“Intake of sweet-tasting beverages may serve a rewarding effect in individuals with depression or predisposed to depression.”
Perhaps the best action plan to take away from the study is to drink plenty of water and unsweetened coffee and tea in moderation.
Source: Tufts University Health & Nutrition Letter, April 2013
Paper presented at a meeting of the Academy of Neurology but not yet published in a peer-reviewed journal.