American Journal of Clinical Nutrition, Vol 34, 2622-2629, Copyright © 1981 by The American Society for Clinical Nutrition, Inc

ORIGINAL RESEARCH COMMUNICATIONS

The inhibitory effect of soy products on nonheme iron absorption in man

JD Cook, TA Morck and SR Lynch

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.

This article has been cited by other articles:

				P. Etcheverry, K. M. Hawthorne, L. K. Liang, S. A. Abrams, and I. J. Griffin Effect of Beef and Soy Proteins on the Absorption of Non-Heme Iron and Inorganic Zinc in Children. J. Am. Coll. Nutr., February 1, 2006; 25(1): 34 - 40. [Abstract] [Full Text] [PDF]

				C. K. Yeung, L. Zhu, R. P. Glahn, and D. D. Miller Iron Absorption from NaFeEDTA Is Downregulated in Iron-Loaded Rats J. Nutr., September 1, 2004; 134(9): 2270 - 2274. [Abstract] [Full Text] [PDF]

				S. R. Lynch and R. J. Stoltzfus Iron and Ascorbic Acid: Proposed Fortification Levels and Recommended Iron Compounds J. Nutr., September 1, 2003; 133(9): 2978S - 2984. [Abstract] [Full Text] [PDF]

				J. H Swain, D L. Alekel, S. B Dent, C. T Peterson, and M. B Reddy Iron indexes and total antioxidant status in response to soy protein intake in perimenopausal women Am. J. Clinical Nutrition, July 1, 2002; 76(1): 165 - 171. [Abstract] [Full Text] [PDF]

				J. H. Swain, L. B. Tabatabai, and M. B. Reddy Histidine Content of Low-Molecular-Weight Beef Proteins Influences Nonheme Iron Bioavailability in Caco-2 Cells J. Nutr., February 1, 2002; 132(2): 245 - 251. [Abstract] [Full Text] [PDF]

				J. D Cook and M. B Reddy Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet Am. J. Clinical Nutrition, January 1, 2001; 73(1): 93 - 98. [Abstract] [Full Text] [PDF]

				L. Hallberg and L. Hulthen Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability of dietary iron Am. J. Clinical Nutrition, May 1, 2000; 71(5): 1147 - 1160. [Abstract] [Full Text] [PDF]

				J. L Beard Effectiveness and strategies of iron supplementation during pregnancy Am. J. Clinical Nutrition, May 1, 2000; 71(5): 1288S - 1294. [Abstract] [Full Text] [PDF]

				A. P. Au and M. B. Reddy Caco-2 Cells Can Be Used to Assess Human Iron Bioavailability from a Semipurified Meal J. Nutr., May 1, 2000; 130(5): 1329 - 1334. [Abstract] [Full Text]

				J P Kaltwasser, E Werner, K Schalk, C Hansen, R Gottschalk, and C Seidl Clinical trial on the effect of regular tea drinking on iron accumulation in genetic haemochromatosis Gut, November 1, 1998; 43(5): 699 - 704. [Abstract] [Full Text] [PDF]