Oxalate contents of species of the Polygonaceae, Amaranthaceae and Chenopodiaceae families

A high dietary oxalate intake influences mineral and trace element absorption in humans and may lead to calcium oxalate stone formation due to the ability of oxalate to form insoluble complexes with divalent cations in the gastrointestinal tract. The soluble and total oxalate contents of species in the Polygonaceae, Amaranthaceae and Chenopodiaceae families were measured using an HPLC-enzyme-reactor method. Polygonaceae, Amaranthaceae and Chenopodiaceae include most of the foods with excessively high oxalate concentrations. Amaranth is a specie of the Amaranthaceae family, Polygonaceae include buckwheat, rhubarb, and sorrel, whereas beetroot, mangold, spinach, and quinoa are species of the Chenopodiaceae family. Obviously, oxalate is accumulated in these plant families in each plant tissue, i.e., in leaves, stems, hypocotyl-root and nuts. The highest oxalate content was found in leaves and stems of plants in these families. Soluble oxalate ranged from 59 to 131 mg/100 g in roots and nuts, and from 258 to 1029 mg/100 g in leaves and stems. Total oxalate ranged from 143 to 232 mg/100 g in roots and nuts, and from 874 to 1959 mg/100 g in leaves and stems. Patients with calcium oxalate stone disease should be advised to avoid these oxalate-rich foods. (c) 2005 Elsevier Ltd. All rights reserved.