December 19, 2009
Green Tea As A Natural Anti-Depressant?
According to a recently released Japanese study, drinking several cups of green tea a day may work as a natural anti-depressant for older men and women, adding yet a another healthful boon to the increasingly researched wonder beverage.
Researchers at Sendai's Tohoku University Graduate School of Biomedical Engineering found that elderly people over the age of 70 who drank four or more cups of green tea per day were 44 percent less likely to struggle with depression than those who drank less than four cups.
A variety of studies in recent years have highlighted the link between green tea consumption and the alleviation of various forms of psychological stress. Dr. Kaijun Niu and his colleagues at Tohuku University took their cue from these studies and decided to investigate whether tea might specifically have a positive impact on symptoms associated with depression.
After examining and questioning 1,058 spry seniors, Niu's team found that around 34 percent of the men and 39 percent of the women reported having some symptoms of depression, with 20 percent of the men and 24 percent of the women having symptoms that could be classified as severe depression.
Of the patients questioned, nearly half said that they consumed at least four cups of green tea per day, while a quarter of them reported that they drank two to three cups a day, and another quarter drank one or less.
The researchers reported in the December issue of the American Journal of Clinical Nutrition that apparent mental health benefits associated with drinking lots of green tea still held true even after other factors were taken into account such as socioeconomic class, diet, smoking, physical activity and history of medical complications.
Niu and fellow scientists also observed that other tea varieties"”like oolong and black tea"”did not appear to demonstrate the same salutary anti-depression benefits as their bitter green cousin.
Though harvested from the same plant as both black and oolong teas, the technique used to dry and prepare green tea permits significantly less oxidation of the leaves, giving it both a different flavor and chemical composition.
One of the chemicals present in green tea is theanine, an amino acid similar to glutamate which is able to cross the blood-brain barrier. Scientists have long suspected that theanine may have general tranquilizing effects on the human brain"”one potential explanation for the apparent anti-depressant benefits observed in the study.
Despite the compelling initial results, however, Niu and his team say that additional studies will be needed to draw a more concrete connection between green tea consumption and mental health.
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