The oxalic acid content of Indian foods

Abstract

Oxalic acid, calcium and phosphorus contents, calcium/oxalic acid and calcium/phosphorus ratio of 10 leaves, edible portion of 14 oxalate rich leafy vegetables and 105 other foods are presented in this paper. Three leafy vegetables, viz., Amaranth and twoChenopodium species were found to accumulate abnormally large amounts of oxalic acid. Substantial amounts of oxalic acid were also detected in the edible portions of 14 leafy vegetables examined. Moderately high contents of oxalic acid were recorded in all varieties of tea leaves. Appreciable amounts of oxalic acid were also observed in almond, brinjal, carrot, coconut, colocasia, gingelly sleeds (black and white), kamrak, karonda, tamrind (pulp), wood apple and yam. It could not be detected in 15 food items. Stem part present in edible portion of leafy vegetables decreases the oxalic acid intake but not substantially. 28 foods had calcium/oxalic acid ratio less than 0.3 and out of these 23 had below 0.2. Calcium/phosphorus ratio was less than unity in 75 foods items.