Charrier Marina J S, Savage Geoffrey P, Vanhanen Leo
Institute of Science and Engineering Techniques, University of Angers, Angers, France.
Asia Pac J Clin Nutr. 2002;11(4):298-301. doi: 10.1046/j.1440-6047.2002.00294.x.
Thirty-two commercially available teas consisting of green, oolong and black teas were bought from supermarkets in Christchurch, New Zealand in June 2001. Fifteen herbal teas were also purchased at the same time. The soluble oxalate content of the infusate made from each of the teas was determined using high pressure liquid chromatography. The mean soluble oxalate contents of black tea in tea bags and loose tea leaves were 4.68 and 5.11 mg/g tea, respectively, while green teas and oolong tea had lower oxalate contents, ranging from 0.23 to 1.15 mg/g tea. The soluble oxalate content of the herbal teas ranged from not detected to 3.00 mg/g tea. A regular tea drinker consuming six cups of tea/day would have an intake of between 26.46 and 98.58 mg soluble oxalate/day from loose black tea, 17.88 and 93.66 mg soluble oxalate/day from black tea in tea bags and a maximum of 18.0 mg/day from herbal teas. The oxalate intake from the regular daily consumption of black teas is modest when compared to the amounts of soluble oxalate that can be found in common foods. However, oxalate in black teas has the potential to bind to a significant proportion of calcium in the milk, which is commonly consumed with the black teas.
2001年6月，从新西兰克赖斯特彻奇市的超市购买了32种市售茶叶，包括绿茶、乌龙茶和红茶。同时还购买了15种花草茶。使用高压液相色谱法测定了每种茶叶冲泡液中的可溶性草酸盐含量。茶包红茶和散叶红茶的平均可溶性草酸盐含量分别为4.68和5.11毫克/克茶叶，而绿茶和乌龙茶的草酸盐含量较低，为0.23至1.15毫克/克茶叶。花草茶的可溶性草酸盐含量在未检出至3.00毫克/克茶叶之间。一名每天饮用六杯茶的普通茶饮者，从散叶红茶中每天摄入的可溶性草酸盐为26.46至98.58毫克，从茶包红茶中每天摄入的可溶性草酸盐为17.88至93.66毫克，从花草茶中每天最多摄入18.0毫克。与常见食物中可发现的可溶性草酸盐量相比，日常饮用红茶摄入的草酸盐量适中。然而，红茶中的草酸盐有可能与通常与红茶一起饮用的牛奶中相当一部分钙结合。
