title: Acute Copper and Ascorbic Acid Supplementation Inhibits Non-heme Iron Absorption in Humans.
abstract: The objective of the study is to determine the effect of copper (Cu) plus the reducing agent ascorbic acid (AA) on the absorption of non-heme iron (Fe). Experimental study with block design in which each subject was his own control. After signing an informed consent, 14 adult women using an effective method of contraception and negative pregnancy test received 0.5 mg Fe, as ferrous sulfate, alone or with Cu, as copper sulfate, plus ascorbic acid (AA/Cu 2/1 molar ratio) at 4/1; 6/1 and 8/1 Cu/Fe molar ratios as an aqueous solution on days 1, 2, 14, and 15 of the study. Fe absorption was assessed by erythrocyte incorporation of iron radioisotopes (55)Fe and (59)Fe. Geometric mean (range ± SD) absorption of Fe at 4/1 and 6/1 Cu/Fe molar ratios (and AA/Cu 2/1 molar ratio) and Fe alone was 57.4 % (35.7-92.1 %), 64.2 % (45.8-89.9 %), and 38.8 % (20.4-73.8 %), respectively (ANOVA for repeated measures p < 0.001; post hoc test Scheffé, p < 0.05). This is attributable to the enhancing effect of AA on non-heme Fe absorption; however, Fe absorption at Cu/Fe 8/1 molar ratio was 47.3 % (27.7-80.8) (p = NS compared with Fe alone). It was expected that Fe absorption would have been equal or greater than at 4/1 and 6/1 molar ratios. Copper in the presence of ascorbic acid inhibits non-heme Fe absorption at Cu/Fe 8/1 molar ratio.
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile. molivare@inta.uchile.cl.
authors.forename: Manuel
authors.initials: M
authors.lastname: Olivares
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile.
authors.forename: Constanza
authors.initials: C
authors.lastname: Figueroa
authors.affiliation: Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Pizarro
mesh_terms: D065567:Absorption, Physiological / Q000187:drug effects*; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology*; D019587:Dietary Supplements; D005260:Female; D005296:Ferrous Compounds / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged
chemical_list: D005296:Ferrous Compounds; C020748:ferrous sulfate; D003300:Copper; D001205:Ascorbic Acid
keywords: Ascorbic acid; Copper; Humans; Iron; Iron absorption