title: Increasing dietary protein acutely augments intestinal iron transporter expression and significantly increases iron absorption in rats.
abstract: Iron (Fe) deficiency is endemic worldwide. Little data are available regarding acute effects of dietary protein on intestinal Fe absorption. The current study evaluated the short-term effects of increasing dietary protein on Fe absorption and expression of genes involved in Fe homeostasis. Sprague Dawley rats (24, female) were randomly assigned to custom-formulated isocaloric diets containing 40, 20 (control), or 5% protein (as percentage of total kilocalories) for 7 d. Whole-body Fe balance studies demonstrated that Fe retention was greater in the 40% group than in the 5% group (30.8 vs. 7.3%; P<0.01). In a separate study utilizing stable iron isotopes, the 40% group absorbed 30% of ingested Fe, while the 20% group absorbed 18% (P=0.005). Whole-genome profiling revealed that increasing dietary protein from 5 to 40% increased duodenal transcript expression of divalent metal transporter 1 (DMT1) 3.2-fold, duodenal cytochrome b (Dcytb) 1.8-fold, and transferrin receptor (TfR) 1.8-fold. Consistent with these findings, DMT1 transcript expression was 4-fold higher in RNA prepared from duodenal mucosa in the 40% group compared to the 20% group (P<0.001). These data suggest that increasing dietary protein increases intestinal Fe absorption in part by up-regulating DMT1, Dcytb, and TfR.
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA. carrie.cucchi@yale.edu
authors: Carrie E
authors: CE
authors: Thomas
authors: Erin
authors: E
authors: Gaffney-Stomberg
authors: Ben-Hua
authors: BH
authors: Sun
authors: Kimberly O
authors: KO
authors: O'Brien
authors: Jane E
authors: JE
authors: Kerstetter
authors: Karl L
authors: KL
authors: Insogna
mesh_terms: D000818:Animals; D002364:Caseins / Q000008:administration & dosage; D027682:Cation Transport Proteins / Q000235:genetics*; D045303:Cytochromes b / Q000235:genetics*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004386:Duodenum / Q000378:metabolism; D038181:FMN Reductase / Q000235:genetics; D005260:Female; D007408:Intestinal Absorption / Q000235:genetics* / Q000502:physiology; D019266:Iron, Dietary / Q000493:pharmacokinetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011990:Receptors, Transferrin / Q000235:genetics*; D015854:Up-Regulation; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D002364:Caseins; D027682:Cation Transport Proteins; D045303:Cytochromes b; D004044:Dietary Proteins; D038181:FMN Reductase; D019266:Iron, Dietary; D012333:RNA, Messenger; D011990:Receptors, Transferrin; D000099236:Solute Carrier Family 11, Member 2; C023903:ferric citrate iron reductase
keywords: DMT1; Dcytb; IRE; microarray