Health and Tea – Posting #2 in a Series
Posted by Melanie Hingle, MPH, RD (Center for Physical Activity and Nutrition, University of Arizona http://cpanarizona.org)
As if we needed more proof that tea is good for you!…a new study published in the journal Cancer Epidemiology Biomarkers & Prevention (by Yang et al. Vol 16, Pages 1219-1223) found a 37% risk reduction for colorectal cancer in a population of 69,710 Chinese women between the ages of 40 and 70. The ones who appeared to derive the most protection from tea were those who “regularly” drink tea. Now, what does “regular” mean? This is always a good question to ask when reading about research studies on diet and behavior.
This particular study doesn’t go into the specifics, but suggests that ‘daily’ intake is associated with a greater protective benefit. Green tea is the most commonly consumed tea in Shanghai so this is the tea that the study has the most information on — so the results aren’t necessarily applicable to other types of tea (although I suspect similar benefits).
With this type of population research, the results can only be broadly applied to the specific population being studied (in this case, middle-aged Chinese women)…however, results are convincing enough to suggest a benefit could be derived from tea drinking behaviors in OTHER populations as well if they used similar quality tea, and prepared it in a similar manner. In Shanghai, “the common method of tea preparation is to brew dry leaves with hot water” according to the authors of this study. I am not certain how this differs from our American way of preparing tea (e.g. I too brew with hot water?) – perhaps they mean versus cold water brewing? If someone knows, please do let me know – I suspect Austin knows!:)
Lastly, an effect was also noted for the “dose” of tea – i.e. longer duration of tea drinking (years) corresponded with significantly lower risk.
Happy tea drinking!
Yes, most teas can be cold brewed, meaning putting leaves in water and waiting, some times a long time. One of the ways for testing quality, especially with green tea, is to cold brew it, watching for the time it takes for the leaves to sink. If the tea is old, it will take much longer. I was recently in Taiwan. We spent a lot of time driving in the mountains and before we would leave everyday the tea master that we were visiting put oolong in a number of commercially bottled water, and we enjoyed great tea brewed in cold water all day. Here in Arizona we also like to but tea in big jars in the back yard to make sun tea.
Austin