|Laparra, Jose Moises|
Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2008
Publication Date: 2/1/2009
Citation: Tako, E., Laparra, J., Glahn, R.P., Welch, R.M., Lei, X., Beebe, S., Miller, D.D. 2009. Biofortified black beans (Phaseolus vulgaris L.) in a maize/bean diet provide more bioavailable iron to piglets than standard black beans. Journal of Nutrition. 139(2):417-422. Interpretive Summary: One of the strategies for reducing nutrient deficiency in poor countries is to try to breed crops that are high in iron, zinc, or other nutrients. However, an increase in nutrient level in the crop does not necessarily translate to increased absorption of the nutrient as other factors that may affect absorption may also change with the increased nutrient content. This study uses pigs as a model to test whether increased iron content in black beans compared to a standard black bean will in fact lead to more available iron for hemoglobin synthesis. Pigs were divided into two groups with one group being fed a diet with black beans with high iron content versus a standard black bean with lower iron content for five weeks and hemoglobin was measured throughout the study. At the end of the study, the increase in total body hemaglobin in the high iron black bean diet group was significantly higher than in the low iron group. This indicates that a biofortified bean may be a good dietary staple to increase iron intakes over a period of time.
Technical Abstract: Our objective was to compare the capacities of biofortified and standard black beans to deliver iron (Fe) for hemoglobin synthesis. Two lines of black beans (Phaseolus vulgaris L.), one standard (“Low”) and the other biofortified (“High”) in Fe (71 and 106 ug Fe/g, respectively) were used. Maize-based diets containing the beans were formulated to meet the nutrient requirements for swine except for Fe (Fe concentrations in the 2 diets were 42.9 +/- 1.2 and 54.6 +/- 0.9 mg/kg). At birth, pigs were injected with 50 mg of Fe as Fe dextran. At age 28 d, pigs were allocated to the experimental diets (n=10). They were fed 2 times per day for 5 weeks and given free access to water at all times. Body weights and hemoglobin concentrations were measured weekly. Hemoglobin repletion efficiency (HRE) values after 5 weeks were 20.8 +/- 2.1 and 20.9 +/- 2.1 % for the low Fe and high Fe groups, respectively, P=0.48. The final total body hemoglobin Fe values were 539 +/- 39 and 592 +/- 28 mg in the low and high Fe bean groups, respectively, P = 0.15. The increase in total body hemoglobin Fe over the 5 week feeding period was greater in the high Fe bean group (429 +/- 24 mg) than in the low Fe bean group (361 +/- 23 mg), P = 0.034. We conclude that the biofortified beans are a promising vehicle for increasing intakes of bioavailable Fe in human populations where beans are a dietary staple.