Submitted to: Topics in Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2001
Publication Date: 2/5/2002
Citation: MASSEY, L.K., GRENTZ, L.M., HORNER, H.T., PALMER, R.G. SOYBEAN AND SOYFOOD CONSUMPTION INCREASES OXALATE EXCRETION. TOPICS IN CLINICAL NUTRITION. 2002. v. 17. p. 49-59. Interpretive Summary: Calcium is the fifth most abundant element in the earth's crust. Its essential role in human health is well understood, what it does in plants is not well understood. In soybean, calcium and an insoluble calcium oxalate follow a developmental sequence. The significance, if any, remains a mystery. Differences in calcium oxalate in seed and soyfoods were measured chemically before samples were fed to humans. Urinary oxalate wa measured. Soybean and soyfoods are capable of increasing urinary oxalate excretion to a high level. This level is defined as increasing the risk of calcium oxalate stone formation in humans. This research will be important not only to human nutritionists and dieticians, but also to soy producers and manufacturers. The frequent consumption of soybean and soyfood products may be a risk factor for kidney stone formation in individuals with a prior history of calcium stones.
Technical Abstract: Eight healthy adults with no prior history of kidney stones participated in eight oxalate (Ox) load tests, including seven foods and an Ox solution control. After correction for endogenous Ox synthesis, increases in urinary Ox excretion during the 8 hours after eating one food ranged from 19.6 +/- 23.3 to 124 +/- 156 umol (1.7 +/- 2.1 to 10.9 +/- 13.8 mg) for the two soybean lines and five soyfoods. Since normal urinary Ox excretio is 110-440 umol (10-39 mg) per day, eating soybeans and soyfoods is capable of increasing urinary Ox excretion to 450 umol (40 mg) or more day, a concentration defined as increasing the risk of calcium Ox stone formation.