FOOD INTERACTIONS AND FACTORS THAT AFFECT IRON BIOAVAILABILITY FROM BEANS AND PEARL MILLET
Plant, Soil and Nutrition Research
2011 Annual Report
1a.Objectives (from AD-416)
We will determine how other foods commonly consumed in combination with beans or pearl millet affect the iron (Fe) bioavailability and absorption of the overall meal. Food interactions will be based on common combinations of targeted countries of Latin America, Asia, and Africa.
1b.Approach (from AD-416)
We will use a combination of in vitro screening coupled with in vivo long term feeding trials of poultry. We previously demonstrated that the chicken model exhibits the appropriate responses to iron (Fe) deficiency and can serve as a model for iron (Fe) bioavailability. These feeding trials will span up to 8 weeks depending on the observed effects of the test diets.
Initially, this project was supposed to examine Fe bioavailability from pearl millet samples sent to us from collaborators in India. However, our collaborators were unable to provide us with samples, hence our research partner in this agreement, HarvestPlus, agreed to shift our focus to transgenic sorghum samples supplied by Pioneer Seeds. The transgenic sorghum samples were engineered to be low in phytic acid (an inhibitor of Fe absorption). Our initial in vitro studies indicate that these transgenic samples, showing a 65-90% reduction in phytic acid have improved Fe biovailability, perhaps as much as 2-3 times that of control samples. However, polyphenolic compounds are high in sorghum, hence a strong inhibitory effect on Fe bioavailability remains. Additional amounts of these lines are being produced this summer so that animal testing to confirm the in vitro results can be conducted.
Combinations of rice and beans and corn and beans were examined to determine if these traditional food combinations exhibit less or more Fe bioavailability than when beans are consumed alone. Our results are interesting as they indicate that corn and red beans have significantly more Fe biovailability than an equal amount of beans alone. For black beans, this effect was not observed. The addition of rice did not enhance Fe bioavailability from the red or black bean meal. The results from combinations of these meals are interesting and have implications for how human studies should be designed to determine if biofortification is effective in meal combinations.