Q. You recently covered a new green tea study that focused on protecting brain cells. How would the dosages used in the study convert into daily cups of green tea?
A. Jeffrey Blumberg, PhD, director of Tufts’ HNRCA Antioxidants Research Laboratory, responds: “It is not possible to determine the green tea cups/day equivalent in that particular study because the authors disclosed the dose only as ‘0.05% standardized green tea extract’ without describing the standard. However, two observational studies of green tea and cognitive performance, published in the American Journal of Clinical Nutrition in 2006 and 2008, identified those drinking two or more cups per day and three to five cups or more per day, respectively, as the ‘high’ dose that was most effective. Other human studies using green tea or green tea extracts generally give doses equivalent to three to five cups per day, though some have gone up to about 10 cups per day.”