Elderly people who drink several cups of green tea a day are less likely to suffer from depression, probably due to a "feel good" chemical found in this type of tea, Japanese researchers said.

    Several studies have linked drinking green tea to lessening psychological problems and Kaijun Niu, of Tohoku University Graduate School, and colleagues found people aged 70 and older who drank four or more cups of green tea daily were 44 percent less likely to experience depression.

    Green tea is widely consumed in many Asian countries, including China and Japan.

    Niu's team investigated 1,058 relatively healthy elderly men and women. About 34 percent of the men and 39 percent of the women had symptoms of depression, according to the study that was published in the the American Journal of Clinical Nutrition.

    A total of 488 participants said they drank four or more cups of green tea a day, 284 said they downed two to three cups daily and the rest reported having one or fewer cups daily.

    According to the researchers, the apparent effect of drinking more green tea on alleviating symptoms of depression did not fade after they factored in social and economic status, gender, diet, history of medical problems and use of antidepressants.

    There was no association between consumption of black or oolong tea, or coffee, and lower symptoms of depression.

    A green tea component, the amino acid theanine, which is thought to have a tranquillising effect on the brain, may explain the "potentially beneficial effect" shown in the current study, Niu noted, adding that more study is needed.

    日本研究人員日前稱，老年人每天喝幾杯綠茶可降低患抑郁癥的風險，這可能是因為綠茶中含有一種能讓人"感覺良好"的化學物質。

    之前的幾項研究發現，喝綠茶有助于減少心理問題。日本東北大學研究生院的丹生介順及其同事發現，每天喝四杯或四杯以上綠茶的70歲及以上的老年人患抑郁癥的幾率比那些不喝綠茶的人低44%.

    在中國和日本等很多亞洲國家，綠茶是一種很流行的飲品。

    丹生的研究小組對1058名相對較健康的老年男性和女性進行了調查，約34%的男性和39%的女性有抑郁癥狀。該研究在《美國臨床營養期刊》上發表。

    共有488名調查對象稱他們每天喝四杯或四杯以上的綠茶，284人說他們每天喝兩到三杯，其他人每天喝一杯或喝得很少。

    研究人員稱，多喝綠茶對于緩解抑郁癥狀有顯著效果，而且即便將社會經濟狀況、性別、飲食、病史和服用抗抑郁藥等因素都考慮進去，這種效果也不會受到影響。

    不過飲用紅茶、烏龍茶或咖啡對減輕抑郁癥狀沒有什么效果。

    丹生指出，綠茶中所含的茶氨酸成分對于大腦有鎮定作用，這或許可以解釋這項研究所發現的綠茶的"潛在益處",不過還需進一步研究加以論證。