Green tea helps reduce the risk of disability in older individuals

Friday, February 3, 2012. A report published online on January 25, 2012 in the American Journal of Clinical Nutrition reveals a lower risk of incident functional disability, such as that caused by cognitive impairment, osteoporosis and stroke, in association with increased green tea intake among older Japanese men and women.

"Epidemiologic studies have indicated that green tea consumption is associated with a lower risk of osteoporosis, and randomized controlled trials have indicated that green tea is effective for cardiovascular risk factors," Yasutake Tomata of Tohoku University and colleagues write in their introduction to the article. "Because all of the above conditions are major causes of functional disability, it is expected that green tea consumption would contribute to disability prevention."

The researchers analyzed data from 13,988 Japanese men and women aged 65 and older who participated in the Ohsaki Cohort 2006 study. Questionnaires completed upon enrollment were analyzed for the frequency of green, oolong and black tea intake, as well as coffee. Over a three year follow-up period, incident functional disability was documented in 1,316 men and women.

For subjects who consumed one to two cups green tea per day, the risk of becoming disabled was 10 percent lower in comparison with those who reported drinking less than a cup per day. The probability of disability declined with greater green tea consumption to a 33 percent lower risk for those whose intake was five cups per day or more. Adjustment for numerous factors failed to significantly modify the association. No associations were determined for coffee, or oolong or black tea after adjusting for various factors.

The authors remark that previous studies have uncovered associations between green tea consumption and a lower risk of stroke, dementia, fracture and depression, all of which can contribute to disability. Green tea polyphenols have also been shown to improve leg strength, thereby reducing frailty, a major disability risk factor.

"To our knowledge, this is the first reported study to have proved the relation between green tea consumption and incident risk of functional disability," the authors announce. They recommend clinical trials to confirm the benefit suggested by the current study's findings.