Joanna Cosgrove03.15.10
For those who have survived a breast cancer diagnosis and the grueling treatment that followed, depression can often come as an unwelcome side effect. Researchers at Vanderbilt University Medical Center in Nashville, TN, examined the association of lifestyle factors and supplement use with depression among breast cancer survivors and found that exercise coupled with green tea consumption might have the ability to lessen breast cancer blues.
“Animal and epidemiological studies have previously suggested that exercise and tea/tea extracts have anti-depressive effects,” commented lead study author Xiao Ou Shu, PhD. “Depression is highly prevalent among breast cancer survivors.”
In a population-based cohort study conducted between April 2002 and December 2006 in Shanghai, China, researchers examined and interviewed a total of 1399 women who were diagnosed with stage 0 to III breast cancer and had a median age of 54 years. Six months after their diagnosis, the researchers assessed the women’s food, tea and alcohol consumption; cigarette smoking; and use of herbal medicines and supplements. Their physical activity levels were also assessed and a metabolic equivalent (MET) score was calculated from reported exercise activities.
At 18 months post-diagnosis, the participants were evaluated for depressive symptoms. An analysis of that data revealed that 62% of women who reported engaging in some sort of exercise experienced benefits, and, according to the study (which was published in the Journal of Clinical Oncology) exercisers were about 20% less likely to be “mildly or clinically depressed.”
The researchers noted there were only 84 cases of mild or clinical depression among 437 vigorous exercisers (19.2%), but 161 cases among the 528 non-exercisers (30.5%).
And, in comparison with non-exercising women, the likelihood of depression was 28% lower among women who exercised more than two hours a week and 42% lower among those who increased their post-diagnosis exercise time.
Tea consumption—specifically, green tea—also proved to be a noteworthy factor in alleviating depression. About 90% of the study participants drank green tea. When researchers compared the results of the study’s 183 tea drinkers with the remaining 1216 women who did not drink tea, they noticed the risk for depression was about 36% lower. Regular tea consumption, as defined by the researchers, was less than 100 grams of dried tea leaves per month. No associations were found for dietary intake or supplement use with depression.
The exercise and tea-drinking benefits remained consistent when the researchers expanded their search for multiple other depression risk factors.
“It is unclear what specific components are responsible for the favorable association that we saw in our study,” said Dr. Shu. He added that potential mechanisms were discussed in the published study.
Although this study documented the mood boosting benefits of exercise in combination with green tea, Dr. Shu said more research is warranted. “For breast cancer patients, increased participation of exercise (low to moderate intensity) should be encouraged,” he said. “Our study is the first to report that tea consumption may decrease the risk of depression among breast cancer patients. More studies will need to confirm our findings. It is premature to make any recommendation based on findings from a single study.”
Dr. Shu and his colleagues are currently conducting a collaborative study, pooling data from four cohort studies of over 18,000 breast cancer patients. “The tea and depression association will be evaluated in this study,” he said.
