About one-fifth(20%) of the U.S. population consumed diet drinks on a given day during 2009-2010, and 11% consumed 16 fl oz of diet drinks or more, according to the report from National Center for Health Statistics.(NCHS) The percentage consuming diet drinks was higher among females compared with males.

Recently, the National Institutes of Health(NIH) found that drinking sodas - particularly artificially sweetened ones- may be linked to depression.  The research will be reported during the American Academy of Neurology's annual meeting in March, 2013. According to the study, soda drinkers 4 cans or more on a daily basis are about 30% more likely to be diagnosed with depression than non-soda drinkers.

"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 Honglei Chen, MD, PhD. who led the study. "More research is needed to confirm these findings, and people with depression should continue to take depression medications prescribed by their doctors."

About 264,000 people between the ages of 50 and 71 participated in this research. The participants consumed  various drinks - soda, fruit punch, coffee and tea - for one year from 1995 to 1996. 10 years later, it was revealed that 11,311 people had been diagnosed with depression.

Diet soda drinkers had a 31 % higher risk of depression than non-soda drinkers, while diet soda drinkers had a 22 % higher risk of depression than regular soda drinkers. Diet fruit punch drinkers had a 51 % higher risk than non-soda/fruit punch drinkers.

According to the statistics from NCHS in October 2012, diet drink consumption differed by age, race and ethnicity, and income. For example, the percentage of non-Hispanic white children and adults who consumed diet drinks was higher than those for non-Hispanic black and Hispanic children and adults. The percentage of higher-income persons who consumed diet drinks was higher than that for lower-income persons.

We can find out an interesting fact that women are consuming diet drinks more than men from the report from NCHS. Here, we might assume one of the reasons that women have depression more than men. The National Institutes of Mental Health(NIMH) revealed that depression affects twice as many women as men and 1 in 4 women will experience severe depression at some point in life. 

"Although switching from regular soda to diet soda may save you calories, some studies suggest that drinking more than one soda a day - regular or diet - increases your risk of obesity and related health problems such as type 2 diabetes," said Mayo Clinic nutritionist Katherine Zeratsky, R.D., L.D.