Green Tea Beats the Blues Among Mature Adults
A study published in the December 2009 issue of the American Journal of Clinical Nutrition found that mature men and women that drink green tea are regularly in a better mood and have a much lower risk of depression.
Japanese researchers from Tohoku University Graduate School of Biomedical Engineering in Sendai, recruited 1,058 healthy individuals over 70 for the study.
The researchers found that participants who drank 4 or more cups of green tea daily had a 44% reduced risk of depression compared to those who drank 1 cup or less.
The link remained even after researchers accounted for social and economic status, gender, diet, history of medical problems, use of antidepressant medications, smoking, and physical activity.
The researchers are confident that the results are not simply due to caffeine because no link was found between depressive symptoms and consumption of oolong tea or coffee, both of which contain caffeine.
Further studies will help to target the mechanism behind these findings. However, the researchers noted that an amino acid called theanine, which has been shown to have a tranquilizing effect on the brain in previous studies, may play a prominent role.
This study builds on the findings of a similar study published in the September 2009 issue of The American Journal of Clinical Nutrition.
The study, which included over 40,000 Japanese men and women, found that 20% of people who drink 5 or more cups of green tea daily have a 20% reduction in psychological stress compared to those who drink 1 cup or less.
The science behind the cognitive benefits of green tea is still growing. However, green tea has already been linked to a number of other health benefits ranging from digestion to protection against some cancers.
These benefits are often attributed to the high amount of naturally occurring antioxidants in green tea called polyphenols. These antioxidants protect our cells from dangerous free radicals. A recent study even found that the cells of regular tea drinkers actually have a younger biological age than non-tea drinkers.