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Open Access Research

Biofortified red mottled beans (Phaseolus vulgaris L.) in a maize and bean diet provide more bioavailable iron than standard red mottled beans: Studies in poultry (Gallus gallus) and an in vitro digestion/Caco-2 model

Elad Tako1*, Matthew W Blair2 and Raymond P Glahn1

Author Affiliations

1 USDA/ARS, Robert W. Holley Center for Agriculture and Health, Cornell University, Ithaca, NY 14853, USA

2 Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia and Department of Plant Breeding, Cornell University, Ithaca NY 14853, USA

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Nutrition Journal 2011, 10:113  doi:10.1186/1475-2891-10-113

Published: 14 October 2011

Abstract

Background

Our objective was to compare the capacities of biofortified and standard colored beans to deliver iron (Fe) for hemoglobin synthesis. Two isolines of large-seeded, red mottled Andean beans (Phaseolus vulgaris L.), one standard ("Low Fe") and the other biofortified ("High Fe") in Fe (49 and 71 μg Fe/g, respectively) were used. This commercial class of red mottled beans is the preferred varietal type for most of the Caribbean and Eastern and Southern Africa where almost three quarters of a million hectares are grown. Therefore it is important to know the affect of biofortification of these beans on diets that simulate human feeding studies.

Methods

Maize-based diets containing the beans were formulated to meet the nutrient requirements for broiler except for Fe (Fe concentrations in the 2 diets were 42.9 ± 1.2 and 54.6 ± 0.9 mg/kg). One day old chicks (Gallus gallus) were allocated to the experimental diets (n = 12). For 4 wk, hemoglobin, feed-consumption and body-weights were measured.

Results

Hemoglobin maintenance efficiencies (HME) (means ± SEM) were different between groups on days 14 and 21 of the experiment (P < 0.05). Final total body hemoglobin Fe contents were different between the standard (12.58 ± 1.0 mg {0.228 ± 0.01 μmol}) and high Fe (15.04 ± 0.65 mg {0.273 ± 0.01 μmol}) bean groups (P < 0.05). At the end of the experiment, tissue samples were collected from the intestinal duodenum and liver for further analyses. Divalent-metal-transporter-1, duodenal-cytochrome-B, and ferroportin expressions were higher and liver ferritin was lower (P < 0.05) in the standard group vs. the biofortified group. In-vitro analysis showed lower iron bioavailability in cells exposed to standard ("Low Fe") bean based diet.

Conclusions

We conclude that the in-vivo results support the in-vitro observations; biofortified colored beans contain more bioavailable-iron than standard colored beans. In addition, biofortified beans seems to be a promising vehicle for increasing intakes of bioavailable Fe in human populations that consume these beans as a dietary staple. This justifies further work on the large-seeded Andean beans which are the staple of a large-region of Africa where iron-deficiency anemia is a primary cause of infant death and poor health status.

Keywords:
Beans; biofortification; iron bioavailability; in vitro digestion/Caco- 2 cell model; broiler chicken; intestine