Iron metabolism in heterozygotes for hemoglobin E (HbE), alpha-thalassemia 1, or beta-thalassemia and in compound heterozygotes for HbE/beta-thalassemia.
BACKGROUND
Despite large populations carrying traits for thalassemia in countries implementing universal iron fortification, there are few data on the absorption and utilization of iron in these persons.


OBJECTIVE
We aimed to determine whether iron absorption or utilization (or both) in women heterozygous for beta-thalassemia, alpha-thalassemia 1, or hemoglobin E (HbE) differed from that in control subjects and compound HbE/beta-thalassemia heterozygotes.


METHODS
In Thai women (n = 103), red blood cell indexes, iron status, non-transferrin-bound iron, and growth differentiation factor 15 were measured, and body iron was calculated. Fractional iron absorption was measured from meals fortified with isotopically labeled ((57)Fe) Fe sulfate, and iron utilization was measured by the infusion of ((58)Fe) Fe citrate.


RESULTS
Iron utilization was approximately 15% lower in alpha-thalassemia 1 or beta-thalassemia heterozygotes than in controls. When corrected for differences in serum ferritin, absorption was significantly higher in the alpha- and beta-thalassemia groups, but not the HbE heterozygotes, than in controls. HbE/beta-thalassemia compound heterozygotes had lower iron utilization and higher iron absorption and body iron than did controls. Nontransferrin-bound iron and growth differentiation factor 15 were higher in the compound heterozygotes, but not in the other groups, than in the controls.


CONCLUSIONS
In alpha-thalassemia 1 and beta-thalassemia heterozygotes with ineffective erythropoesis, dietary iron absorption is not adequately down-regulated, despite a modest increase in body iron stores. In populations with a high prevalence of these traits, a program of iron fortification could include monitoring for possible iron excess and for iron deficiency.
Laboratory for Human Nutrition, Swiss Federal Institute of Technology Zürich, Zürich, Switzerland. michael.zimmermann@ilw.agrl.ethz.ch
Michael B
MB
Zimmermann
Suthat
S
Fucharoen
Pattanee
P
Winichagoon
Pornpan
P
Sirankapracha
Christophe
C
Zeder
Sueppong
S
Gowachirapant
Kunchit
K
Judprasong
Toshihiko
T
Tanno
Jeffery L
JL
Miller
Richard F
RF
Hurrell
D000293:Adolescent; D000328:Adult; D001682:Biological Availability; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005527:Food, Fortified; D005838:Genotype; D006446:Hemoglobin E / Q000235:genetics / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D007408:Intestinal Absorption; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D007503:Iron Isotopes; D019266:Iron, Dietary / Q000493:pharmacokinetics*; D008875:Middle Aged; D009752:Nutritional Status; D013789:Thalassemia / Q000150:complications / Q000235:genetics / Q000378:metabolism*; D017085:alpha-Thalassemia / Q000150:complications / Q000235:genetics / Q000378:metabolism; D017086:beta-Thalassemia / Q000150:complications / Q000235:genetics / Q000378:metabolism
D007503:Iron Isotopes; D019266:Iron, Dietary; D006446:Hemoglobin E; D007501:Iron