Iron Absorption from an Intrinsically Labeled Lentil Meal Is Low but Upregulated in Women with Poor Iron Status.
BACKGROUND
Low iron absorption from important staple foods may contribute to iron deficiency in developing countries. To date, few studies have examined the iron bioavailability of pulse crops as commonly prepared and consumed by humans.


OBJECTIVE
The objectives were to characterize the iron absorption from a test meal of intrinsically labeled (57)Fe lentils prepared as dal, to compare the bioavailability of iron from (57)Fe in dal with that observed for a reference dose of (58)Fe as ferrous sulfate, and to assess associations between iron absorption and iron status indicators.


METHODS
This crossover study included 19 nonpregnant women (n = 6 anemic; hemoglobin: <12.0 g/dL) who consumed 2 test meals on consecutive days in a counter-balanced order, ferrous sulfate (7 mg FeSO4 plus 1 mg (58)Fe) and 330 g dal (lentils enriched to 85.1% with (57)Fe, 8 mg native (57)Fe). Iron absorption was determined by analyzing blood samples taken 14 d after dosing with the use of magnetic sector thermal ionization mass spectrometry.


RESULTS
We found that the mean iron absorption from the dal was 2.20% ± 3.40% and was significantly lower than the 23.6% ± 13.2% observed from the same iron load given as ferrous sulfate (P < 0.001). Absorption of non-heme iron from dal and from ferrous sulfate was inversely associated with serum ferritin (SF; r = -0.50, P = 0.05 and r = -0.81, P < 0.001, respectively) and serum hepcidin (r = -0.45, P = 0.05 and r = -0.60, P = 0.007, respectively). Anemic women absorbed more iron from either source (1.20% from dal, P = 0.10; 18.3% from ferrous sulfate, P = 0.001) compared with women who were iron replete.


CONCLUSIONS
Iron absorption from the dal was low overall but upregulated in anemic women. Both SF and hepcidin were inversely associated with iron absorption from both a supplemental and a food-based non-heme iron source in nonanemic and anemic women.
Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, USDA, Ithaca, NY; and ddellavalle@hotmail.com.
Diane M
http://orcid.org/0000-0002-3855-432X
DM
DellaValle
Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, USDA, Ithaca, NY; and.
Raymond P
RP
Glahn
Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, USDA, Ithaca, NY; and.
Jon E
JE
Shaff
Division of Nutritional Sciences, Cornell University, Ithaca, NY.
Kimberly O
KO
O'Brien
D000293:Adolescent; D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000178:diet therapy / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007503:Iron Isotopes; D019266:Iron, Dietary / Q000378:metabolism* / Q000627:therapeutic use; D027806:Lens Plant / Q000737:chemistry*; D062407:Meals; D009518:New York; D009752:Nutritional Status; D009753:Nutritive Value; D012639:Seeds / Q000737:chemistry*; D015854:Up-Regulation; D055815:Young Adult
D015415:Biomarkers; D007503:Iron Isotopes; D019266:Iron, Dietary
absorption; bioavailability; iron; lentils; non-heme; pulses