Daily Supplementation with Iron Increases Lipid Peroxidation in Young Women with Low Iron Stores SARAH M. KING,* ,1 CARMEN M. DONANGELO, MITCHELL D. KNUTSON,* ,2 P ATRICK B. W ALTER,à ,3 BRUCE N. AMES,à ,3 FERNANDO E. VITERI,* ,3,4 AND JANET C. KING§ ,3 *Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720;  Laborato ´ rio de Bioquı ´mica Nutricional e de Alimentos, Departamento de Bioquimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, 21949–900 Rio de Janeiro, Brazil; àDepartment of Molecular and Cell Biology, University of California, Berkeley, California 94720; and §USDA Western Human Nutrition Research Center, Davis, California 95616 The aim of this study was to determine whether women with low iron stores (plasma ferritin  20 lg/L) receiving a daily iron supplement for 8 wks at a level commonly used to treat poor iron status develop increased lipid peroxidation as measured by ethane exhalation rates and plasma malondialdehyde. The women served as their own control as pre- and post-supple- mentation periods were compared. Twelve women participated in the study for a 70-day period and consumed daily iron supplements (98 mg of iron as ferrous sulfate) from day 14 to day 70. Baseline blood and expired air samples were obtained on days 1 and 14; measurements during supplementation were performed on days 56 and 70, that is at 6 and 8 weeks of supplementation. Iron status improved during the iron supple- mentation period; biochemical indicators of lipid peroxidation also increased. After 6 wks of iron supplementation, serum ferritin almost doubled and body iron more than doubled. Hemoglobin levels increased slightly and other indicators of iron status became normal. However, plasma malondialdehyde (MDA) and breath ethane exhalation rates (BEER) increased by more than 40% between baseline and 6 wks of supplementation; these increases correlated significantly with plasma iron and ferritin levels. MDA was positively correlated with BEER. BEER increased further after 8 wks of iron supplementation. The increased indicators of lipid peroxidation with duration of supplementation and as iron status improved suggest that providing daily nearly 100 mg iron may not be a totally innocuous regimen for correcting iron depletion in women. Exp Biol Med 233:701–707, 2008 Key words: iron; supplements; malondialdehyde; breath ethane; lipid peroxidation; oxidative stress; iron status; women Introduction Iron supplements are almost universally recommended to pregnant women in most countries at doses ranging from 30–120 mg/day (1). The International Anemia Consultative Group (2) recommends 60 to 120 mg supplemental iron per day for pregnancy; the higher dose is recommended for areas where the prevalence of anemia is high among women of childbearing age. These recommendations exceed the iron RDA for pregnant women by 2- to 3-fold (3). It is recognized that excess body iron and ‘‘free iron’’ stimulate lipid peroxidation that leads to cell and tissue damage (4–6). Yet, only a few studies have been conducted to investigate the effect of iron supplementation on oxidative stress in humans and results are inconclusive (7–11). Animal studies have demonstrated that excess iron increases lipid peroxidation (12–14). Lipid peroxidation is often assessed by measuring endproducts of peroxidation such as plasma malondialdehyde (MDA) and breath ethane and pentane (15). In a study by Knutson et al. (16) healthy women given 120 mg oral iron supplements daily for 28 CMD acknowledges a research fellowship from Conselho Nacional de Desenvolvi- mento Cientı ´fico e Tecnolo ´gico (CNPq), Brazil. 1 Current address: Department of Medicine (Cardiology), Medical College of Georgia, Augusta, GA 30912. 2 Current address: Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL 32607. 3 Current address: Children’s Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609. 4 To whom correspondence should be addressed at Children’s Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609. E-mail fviteri@chori.org Received August 20, 2007. Accepted January 7, 2008. 701 DOI: 10.3181/0708-RM-233 1535-3702/08/2336-0701$15.00 Copyright Ó 2008 by the Society for Experimental Biology and Medicine