Oxalic Acid and Calcium Contents in Tea

Abstract

Daily intake of tea was examined by means of a questionnaire survey of Sadou teachers in Aichi and Kyoto prefectures from the viewpoint of preventing urinary stones by calcium oxalate. The oxalic acid and calcium contents in tea (Maccha, Gyokuro, Sencha, Bancha and Black tea) were determined and their balance was calculated. Average calcium shortages calculated from the intake of oxalic acid per cup of tea were 10.23mg in Maccha, 5.26mg in Black tea, 2.21mg in Gyokuro, 1.87mg in Sencha, and 0.81mg in Bancha, and consequently daily intake of a cup of milk is recommended to counterbalance the deficit of calcium arising from tea drinking. © 1991, Japanese Society for Food Hygiene and Safety. All rights reserved.