Effects of oxalic acid on availability of zinc from spinach leaves and zinc sulfate to rats
Welch, R.M.; House, W.A.; Van Campen, D.
Journal of Nutrition 107(6): 929-933
1977
ISSN/ISBN: 0022-3166 PMID: 864521 Document Number: 113420
Male rats fed on Zn-deficient diets with and without added sodium oxalate were given by mouth one dose of either [65Zn]spinach leaves or 65Zn as the sulphate. Spinach plants (Spinacia oleracea, var. Winter Bloomsdale) were grown in [65Zn]nutrient solutions that contained Zn 0.033, 0.131 or 0.262/106. Increasing Zn supply to the plants increased Zn concentration in the leaves. Oxalic acid content in all leaves was about 7% dry weight. Dietary oxalate enhanced the availability of 65Zn from the sulphate, but had no effect on absorption and retention of 65Zn from spinach leaves. Regardless of dietary oxalate, absorption and retention of 65Zn was greater from spinach leaves than from zinc sulphate.