ARS | Publication request: ASSESSMENT OF CONCENTRATIONS OF TRACE MINERALS AND BIOAVAILABLE IRON IN GRAINS OF EARLY-MATURING TROPICAL MAIZE VARIETIES

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 1, 2003
Publication Date: June 15, 2003
Citation: OIKEH, S.O., MENKIR, A., MAZIYA-DIXON, B., WELCH, R.M., GLAHN, R.P. ASSESSMENT OF CONCENTRATIONS OF TRACE MINERALS AND BIOAVAILABLE IRON IN GRAINS OF EARLY-MATURING TROPICAL MAIZE VARIETIES. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY. 2003. v. 51. p. 3688-3694.

Interpretive Summary: Enhancing the nutritional quality of staple food crops via traditional plant breeding methods can produce high-yielding and more nutritious foods. These agricultural methods are a cost effective & sustainable way to alleviate the high rate of mineral & micronutrient malnutrition in humans of West Africa. With this overall objective, we evaluated twenty early-maturing corn varieties grown in three diverse agroecologies of West Africa. The goal was to identify varieties with high Fe and Zn levels and with greater Fe bioavailability. Bioavailable iron was assessed using an in vitro digestion/Caco-2 cell model. Across locations, varietal differences were observed in kernel-Fe and -Zn levels; however, the ranges in kernel Fe and Zn levels were small. Most of the variation in kernel-Fe levels was due to environment, and interaction between variety and the environment. The genetic component accounted for 34% of the total variation in kernel-Zn levels. Significant differences in Fe bioavailability were found among varieties. The results indicate that varietal differences exist in grain-iron and -zinc levels, and in bioavailable Fe among early-maturing varieties, but further research is needed to assess if the differences are stable and sufficient to improve the iron status of the consumers.

Technical Abstract: Enhancing the nutritional quality of staple food crops is a cost effective and sustainable way to alleviate micronutrient malnutrition in humans. We evaluated 20 early-maturing (75-90 d) tropical corn varieties grown in 3 diverse agroecologies in West Africa to identify varieties with high Fe & Zn levels. Bioavailable iron was assessed using an in vitro digestion/Caco-2 cell model. Across locations, varietal differences were observed in kernel-Fe and -Zn levels (p< 0.001). The ranges in kernel Fe and Zn levels were small, 15.5 to 19.1 mg kg-1 for Fe & 16.5 to 20.5 mg kg-1 for Zn, with means of 17.4 mg kg-1 for Fe & 18.6 mg kg-1 for Zn. Most of the variation in kernel-Fe levels was due to environmental, & variety x environment (G x E) effects. The genetic component accounted for 34% of the total variation in kernel-Zn levels. Significant differences in Fe bioavailability were found among varieties. Mean bioavailable Fe in varieties across locations, ranged between 10% below to 55% above the control. A significant negative relationship was detected between kernel-P concentration & iron bioavailability (R2= -0.32; P<0.01). At the location with the highest grain-Ca, a positive relationship (R2= 0.44; P<0.05) was found between grain-Ca & bioavailable Fe in among varieties. The results indicate that varietal differences exist in grain-iron & -zinc levels, & in bioavailable Fe among early-maturing varieties, but further research is needed to assess if the differences are stable & can alleviate iron deficiency in humans.