Oxalate and Phytate of Soy Foods

Abstract

The consumption of foods made from soybeans is increasing because of their desirable nutritional value. However, some soy foods contain high concentrations of oxalate and/or phytate. Oxalate is a component of calcium oxalate kidney stones, whereas phytate is an inhibitor of calcium kidney stone formation. Thirty tested commercial soy foods exhibited ranges of 0.02−2.06 mg oxalate/g and 0.80−18.79 mg phytate/g. Commercial soy foods contained 2−58 mg of total oxalate per serving and 76−528 mg phytate per serving. Eighteen of 19 tofu brands and two soymilk brands contained less than 10 mg oxalate per serving, defined as a low oxalate food. Soy flour, textured vegetable soy protein, vegetable soybeans, soy nuts, tempeh, and soynut butter exhibited greater than 10 mg per serving. The correlation between oxalate and phytate in the soy foods was significant (r = 0.71, P < 0.001) indicating that oxalate-rich soy foods also contain higher concentrations of phytate. There also was a significant correlation, based on molar basis, between the divalent ion binding potential of oxalate plus phytate and calcium plus magnesium (r = 0.90, P < 0.001) in soy foods. Soy foods containing small concentrations of oxalate and moderate concentrations of phytate may be advantageous for kidney stone patients or persons with a high risk of kidney stones. KeywordsDepartments of Genetics, Development and Cell Biology, Calcium; kidney stones; oxalate; phytate; soy foods The correlation between oxalate and phytate in the soy foods was significant (r ) 0.71, P < 0.001) indicating that oxalate-rich soy foods also contain higher concentrations of phytate. There also was a significant correlation, based on molar basis, between the divalent ion binding potential of oxalate plus phytate and calcium plus magnesium (r ) 0.90, P < 0.001) in soy foods. Soy foods containing small concentrations of oxalate and moderate concentrations of phytate may be advantageous for kidney stone patients or persons with a high risk of kidney stones.

Effect of Post-Harvest Traditional Technologies on the Nutrient Content and Antioxidant Compounds of Defatted Flours from Ricinodendron heudelotti (Baill. Pierre ex Pax) Seed Kernels

“…The content in the samples could be related to the longer or shorter cooking time [38]. In our samples, the magnesium content was similar to the amounts found in the soya flours [47]. Phosphorus (P) levels, present in small amounts in samples, are lower than phosphorus content in rapeseed meal [44].…”

Comparison of enhancement in bioaccessible iron and zinc in native and fortified high‐phytate oilseed and cereal composites by activating endogenous phytase

“…Phytic acid content of cereals ranges from 0.1% to 2.2%, legumes from 0.2% to 2.9% and oilseeds from 1% to 5% on a dry-weight basis (Chen, 2004;Al-wahsh et al, 2005;Lestienne et al, 2005). It is reported that vegetarian diets contain around 1560-2500 mg (per day) of phytic acid, which is much higher than the western diets containing animal foods (Schlemmer et al, 2009).…”

Soybean: Friend or Foe

“…People with higher risk of development of calcium-oxalate kidney stones should limit their intake of soy. Many soy foods are rich in oxalates and thus may promote the formation of such stones in those at risk (Al-Wahsh et al, 2005). On the other hand, soybean is associated with health benefits for patients with gallstones.…”