title: The effect of soy protein isolate in the diet on retention by the rat of iron from radiolabeled test meals.
abstract: The influence of soy protein isolate (SPI) in the diet on whole-body retention of extrinsically radiolabeled iron from test meals containing or not containing SPI was evaluated in marginally iron-deficient weanling rats. In experiment 1 SPI was compared with casein in a 2 X 2 factorial design: diets and test meals were either SPI-based or casein-based. Diets were fed for 13 days prior to the test meal and for 7 days subsequent to the test meal. Rats fed the SPI-based diet retained less iron from test meals than did rats fed the casein-based diet (66.1 vs. 74.8%, P less than 0.01). Experiment 2 showed that an SPI-based diet fed during the final 4 days of a 14-day pre-test meal period and subsequent to the test meal led to less iron retention compared to a casein-based diet. In addition to the observed diet effect, experiment 1 showed that iron retention was less from an SPI-based test meal than from a casein-based test meal, confirming previous reports of adverse effects of SPI on iron retention. The present experiments show that SPI can adversely affect from retention in two ways: by its presence in the diet before and after a test meal, and by its presence in a test meal.
mesh_terms: D000818:Animals; D004044:Dietary Proteins / Q000494:pharmacology*; D007408:Intestinal Absorption; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D007504:Iron Radioisotopes; D008297:Male; D014674:Plant Proteins, Dietary / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D030262:Soybean Proteins
chemical_list: D004044:Dietary Proteins; D007504:Iron Radioisotopes; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins; D007501:Iron