Randomized, double-blind, placebo-controlled trial of an iron-fortified food product in female soldiers during military training: relations between iron status, serum hepcidin, and inflammation.
BACKGROUND
Iron status degrades in female soldiers during military training. Inflammation-mediated up-regulation of hepcidin, a key mediator of iron homeostasis, may be a contributing factor.


OBJECTIVE
We measured the efficacy of an iron-fortified food product for maintaining iron status in female soldiers during basic combat training (BCT) and examined relations between iron status, serum hepcidin concentrations, and inflammation.


METHODS
A randomized, double-blind, placebo-controlled trial was conducted. Volunteers received an iron-fortified food product (total dose = 56 mg Fe/d) or a placebo twice daily during the 9-wk BCT course. Iron-status indicators, serum hepcidin concentrations, and markers of inflammation were measured pre- and post-BCT.


RESULTS
BCT affected iron status; serum ferritin concentrations decreased (P < or = 0.05), and concentrations of soluble transferrin receptor (sTfR) and hemoglobin and the red cell distribution width increased (P < or = 0.05). Consumption of the iron-fortified food product attenuated declines in iron status in iron-deficient anemic soldiers; a group-by-time interaction was observed for hemoglobin and sTfR concentrations (P < or = 0.05). Serum hepcidin concentrations were not affected by BCT; however, hepcidin concentrations were lower in iron-deficient anemic soldiers than in those with normal iron status (P < or = 0.05) and were positively associated with serum ferritin (P < or = 0.05) and C-reactive protein (P < or = 0.05) concentrations pre- and post-BCT.


CONCLUSIONS
Twice-daily consumption of an iron-fortified food product improved iron status in iron-deficient anemic soldiers but not in iron-normal or iron-deficient nonanemic soldiers. Serum hepcidin concentrations were not affected by training but were associated with iron status and inflammation pre- and post-BCT. This trial was registered at clinicaltrials.gov as NCT01100905.
Karl
J Philip
JP
US Army Research Institute of Environmental Medicine, Natick, MA, USA.
Lieberman
Harris R
HR
Cable
Sonya J
SJ
Williams
Kelly W
KW
Young
Andrew J
AJ
McClung
James P
JP
D000293:Adolescent; D000328:Adult; D023181:Antimicrobial Cationic Peptides / Q000097:blood*; D005006:Ethnicity; D005260:Female; D005293:Ferritins / Q000097:blood; D005527:Food, Fortified; D006454:Hemoglobins / Q000378:metabolism; D064451:Hepcidins; D006801:Humans; D007249:Inflammation / Q000453:epidemiology*; D007501:Iron / Q000097:blood; D019266:Iron, Dietary / Q000378:metabolism / Q000627:therapeutic use*; D008889:Military Personnel; D015596:Nutrition Assessment; D018579:Patient Selection; D010919:Placebos; D044469:Racial Groups; D055815:Young Adult
D023181:Antimicrobial Cationic Peptides; C578702:HAMP protein, human; D006454:Hemoglobins; D064451:Hepcidins; D019266:Iron, Dietary; D010919:Placebos; D005293:Ferritins; D007501:Iron