1 Groundwork LLC, Crans-près-Céligny, Switzerland; 2 Department of Medical Biology, School of Medicine, College of Medicine and Health Sciences, University of Rwanda, Huye, Rwanda; 3 Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria - Unità di Ricerca per l’Orticoltura (CRA-ORL), Montanaso Lombardo, LO, Italia; 4 International Food Policy Research Institute, Washington, DC, United States; 5 Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland.
Background: Phytic acid inhibits the absorption of iron, and the high concentration of phytic acid in biofortified beans might limit their ability to improve iron status. Objective: The present study evaluated iron bioavailability from low phytic acid (lpa) and biofortified bean varieties in Rwandese women with low iron status. Methods: Dietary iron absorption from an lpa bean, an iron biofortified bean (BB) and a control bean (CB) was assessed. We recruited twentyfive women with low iron status (PF<25 μg/l) and administered the beans in a multiple meal crossover design. Iron absorption was measured by the erythrocyte incorporation of stable iron isotopes. Results: Fractional iron absorption from the lpa bean, BB and CB were 8.6%, 7.3% and 8.0% respectively. The total amount of iron absorbed from lpa bean and BB was 340 μg and 404 μg and did not differ significantly, but was 45% (P<0.005) and 72% (P<0.001) higher, respectively, when compared to the control bean (235 μg). In our trial, lpa beans were hard to cook and their consumption caused moderate but transient digestive problems in the participants. Conclusions: Our results show that the BB and lpa bean both provided more bioavailable iron than the CB, but absorption from the lpa bean was similar to the BB, and generally non-consistent with its low phytic acid content. In lpa beans, further breeding steps are required to improve the cooking and digestive properties.