Iron absorption by human subjects from different iron fortification compounds added to Thai fish sauce.
OBJECTIVE
(a) To measure iron absorption by human subjects from citric acid stabilized fish sauce fortified with ferrous sulfate, ferric ammonium citrate or ferrous lactate and (b) to identify the effect of added citric acid (3 g/l) on iron absorption from ferrous sulfate fortified fish sauce.


METHODS
Iron absorption from the intrinsically labeled compounds was determined via erythrocyte incorporation of isotopic labels ((57)Fe and (58)Fe) using a randomized crossover design. In three separate absorption studies, 10 adult women each consumed a basic test meal of rice and vegetable soup seasoned with isotopically labeled, iron fortified fish sauce.


RESULTS
Iron absorption was significantly lower from ferrous lactate and from ferric ammonium citrate fortified fish sauce than from ferrous sulfate fortified fish sauce. Fractional iron absorption (geometric mean; -1s.d., +1s.d.) was 8.7(3.6; 21.4)% for ferrous lactate compared to 13.0(5.4; 31.4)% from ferrous sulfate, P = 0.003 (study 1) and 6.0(2.5; 14.3)% from ferric ammonium citrate relative to 11.7(4.4; 30.7)% from ferrous sulfate, P < 0.001, in study 2. Citric acid added at a molar ratio of approximately 2.5 to iron had no effect on iron absorption from ferrous sulfate (study 3). Iron absorption in the presence of citric acid was 14.1(6.4; 30.8)% compared to 12.0(5.8; 24.7)% in its absence (P = 0.26).


CONCLUSIONS
Iron absorption was 50-100% higher from ferrous sulphate fortified fish sauce than from fish sauce fortified with ferric ammonium citrate or ferrous lactate. In the presence of citric acid as a chelator, ferrous sulfate would appear to be a useful fortificant for fish sauce.


BACKGROUND
International Atomic Energy Agency (IAEA), Vienna, Austria.
Walczyk
T
T
Laboratory of Human Nutrition, Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland. thomas.walczyk@ilw.agrl.ethz.ch
Tuntipopipat
S
S
Zeder
C
C
Sirichakwal
P
P
Wasantwisut
E
E
Hurrell
R F
RF
D000293:Adolescent; D000328:Adult; D019343:Citric Acid / Q000008:administration & dosage / Q000494:pharmacology; D018592:Cross-Over Studies; D005260:Female; D005290:Ferric Compounds / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D005296:Ferrous Compounds / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D005396:Fish Products; D005527:Food, Fortified; D006801:Humans; D007503:Iron Isotopes / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D019266:Iron, Dietary / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D007773:Lactates / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D000644:Quaternary Ammonium Compounds / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D012016:Reference Values
D005290:Ferric Compounds; D005296:Ferrous Compounds; D007503:Iron Isotopes; D019266:Iron, Dietary; D007773:Lactates; D000644:Quaternary Ammonium Compounds; D019343:Citric Acid; C020748:ferrous sulfate; C101012:ferrous lactate; C013531:ferric ammonium citrate