title: The inhibitory effect of soy products on nonheme iron absorption in man.
abstract: Radioiron absorption studies were performed in male volunteer subjects to determine the effect on nonheme iron absorption of various semipurified proteins. When egg albumen and casein were substituted in protein-equivalent quantities in a semisynthetic meal, similar mean absorptions of 2.5 and 2.7% were observed. In contrast, isolated soy protein reduced absorption sharply, to an average of 0.5%. When egg albumen in the semisynthetic meal was replaced with full fat soy flour, textured soy flour, and isolated soy protein, absorption fell from 5.5 to 1.0, 1.9, and 0.4%, respectively, indicating an inhibitory effect by a wide range of soy products. The effect of substituting textured soy flour for meat in a meal containing a hamburger, french fries, and a milkshake was also evaluated. With 3:1 and 2.1 ratios of meat to unhydrated textured soy flour, absorption decreased by 61 and 53%, respectively. The soy products tested in this study have a pronounced inhibitory effect on the absorption of nonheme iron.
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D002364:Caseins / Q000494:pharmacology; D004044:Dietary Proteins / Q000494:pharmacology*; D005433:Flour; D006801:Humans; D007501:Iron / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010047:Ovalbumin / Q000494:pharmacology; D013025:Glycine max
chemical_list: D002364:Caseins; D004044:Dietary Proteins; D010047:Ovalbumin; D007501:Iron