Soybeans and Kidney Stones?

Soybeans and Kidney Stones?

AMES, Iowa--In the September Journal of Agricultural and Food Chemistry (49(9):4262-6, 2001) (www.acs.org), researchers found that soybeans are relatively high in total oxalate, a compound that can bind with calcium to form kidney stones. Led by Linda Massey, Ph.D., from Washington State University in Spokane, researchers found that 11 varieties of soybeans showed relatively high levels of oxalate, from .67 to 3.5 g/100 g of dry weight. These values rate comparatively high compared to other legumes such as peanut butter (197 mg) and lentils (100 mg). Because oxalate cannot be metabolized, it is excreted by the kidney through the urinary tract, which may result in kidney stones.

However, the industry reported that linking kidney stones with soybeans is "bogus." "[I]n fact, soy contains phytic acid which breaks up calcifications and is an antidote to stone formation," reported Bill Sardi, president of Knowledge of Health Inc. of San Dimas, Calif. He added that releasing this study was "irresponsible" and will lead many adults to needlessly avoid soy products.

Alice Chang, M.D., of Harvard Medical School, stated in an article that kidney stones are formed by calcium, not soy. "[I]f you think about it, cultures that commonly include soy products in their diet do not have a higher risk of kidney stones," Chang concluded.