Skip the diet soda and pick up a cup of joe? New research claims that sweetened beverages increase the risk of depression in older adults, while coffee slightly lowers the chances.
"Sweetened beverages, coffee and tea are commonly consumed worldwide and have important physical -- and may have important mental -- health consequences," study author Dr. Honglei Chen, a researcher with the National Institutes of Health in Research Triangle Park in North Carolina and a member of the American Academy of Neurology, said in a written statement.
Chen's new study looked at data from 263,925 people between the ages of 50 and 71 that were first collected from 1995 to 1996. Soda, tea, fruit punch and coffee consumption was recorded for all participants, then researchers followed up about 10 years later and asked the participant if he or she had been diagnosed with depression since 2000.
Out of all the subjects, 11,311 had been diagnosed with depression in that time frame. It was discovered that people who drank more than four cans or cups of soda per day were 30 percent more likely to be depressed than those who did not drink sweetened drinks. Diet drinkers had a higher chance of being diagnosed than their counterparts who drank the regular versions of soda, fruit punch and iced tea respectively.
Coffee drinkers who consumed four or more cups of coffee a day had a 10 percent lower chance of having depression.
"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. "More research is needed to confirm these findings, and people with depression should continue to take depression medications prescribed by their doctors."
However, some doctors are skeptical that a connection between drinking sugary drinks and becoming depressed exists.
"There is much more evidence that people who are depressed crave sweet things than there is to suggest that sweetened beverages cause depression," Dr. Kenneth M. Heilman, a professor of neurology at the University of Florida College of Medicine in Gainesville, said to WebMD.
Heilman added that studies like these do not show a cause and effect, so telling people to cut down on drinking sweetened beverages may not affect depression levels at all.
In addition, the American Beverage Association issued this statement to CBSNews.com: "We may be in a new year, but there is nothing new about the ways our critics try to attack our industry. This research is nothing more than an abstract - it has not been peer-reviewed, published or even, at the very least, presented at a scientific meeting. Furthermore, neither this abstract nor the body of scientific evidence supports that drinking soda or other sweetened beverages causes depression. Thus, promoting any alleged findings without supporting evidence is not only premature, but irresponsible."
Gaynor Bussell, dietician and spokesperson for the British Dietetic Association emphasized to the BBC that this study only showed a link, not a reason for depression. He believes it was a "one-off" study that may or may not be replicated, and added drinking diet drinks can be a marker of diabetes, which is known to cause depression. Bussell said that people may believe after reading the study that their soda caused their depression, especially in the U.S. where sweetened beverages are "demonized."
"Non-calorific sweeteners can play a useful role in the diets of those trying to lose weight and diabetics and it is certainly not advocated that people should replace their diet sodas with more coffee," he said.
The study will be presented at the American Academy of Neurology's 65th Annual Meeting in San Diego, March 16 to 23, 2013, but the results, which are considered preliminary, were released on Jan. 9.