Investigation of daily conditions of green tea drinking and catechins intake in Saitama prefecture [Japan]
2004
Takahashi, A. (Saitama-ken. Greenery Promotion Center, Kawaguchi (Japan)) | Nakajima, K. | Okada, I. | Kajiura, K. | Shimazaki, Y.
To elucidate the amount of major catechins in 10 Japanese-cups of green tea, the number of cups reported effective for cancer prevention, we conducted two investigations: conditions of extraction among 29 people, and determination of major catechins content in daily green tea consumption among 146 people (male: 33, female: 113). First, we found that conditions of extraction varied widely among individuals: The amount of green tea leaf used varied from 1.9 to 9.6 g, and elapsed times for extraction were from 12 to 107 seconds. The study indicated that use of a large quantity of tea leaf and longer extraction time increased intake of major catechins. Second, daily consumption of green tea ranged from 0 - 15 cups per day. The estimated average major catechins intake was 481.0 mg (range: 0 - 2722.9 mg) for those extracting green tea themselves. Those consuming at least 10 cups a day - effective for prevention of cancer - numbered only 11.6 % and these subjects were getting an estimated average of 1299.0 mg of major catechins per day. Older tea drinkers drank more cups per day than the young, and the more frequently they drank, the more major catechins they took in, indicating that greater knowledge of the health benefits of green tea is necessary, especially for the young and (in our study) men. Based on our studies, we recommend getting at least 10 cups (155ml/cup) or about 1.3 g of major catechins per day: Effective ways of taking this amount are increasing both the amount of green tea leaf used and the brewing time.
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