Iron absorption from maize (Zea mays) and sorghum (Sorghum vulgare) beer

1. Iron absorption from maize (Zea mays) and sorghum (Sorghum vulgare) beer was more than twelve-fold greater than from a gruel made from the constituents used to prepare the beer. 2. The effect of changes occurring during brewing were investigated. These changes include a decrease in the solid content, and the formation of 30 ml ethanol/1 and 5 ml lactic acid/1. 3. The presence of solid material was found to inhibit Fe absorption markedly, especially when the solid content was 100 g/l or more. 4. The presence of ethanol potentiated Fe absorption but the effect was only modest in gruels with a high solid content. 5. Fe absorption from a 2 ml lactic acid/l solution was four-fold greater than from a hydrochloric acid solution of the same pH. When lactic acid was added to a gruel containing 200 g solids/l the mean absorbtion rose from 0.4 to 1.2 %. 6. In a direct comparison, Fe absorption from beer was significantly better than from a gruel of similar pH containing lactic acid. 7. The results suggest that at least three factors are responsible for the enhanced Fe absorption from maize and sorghum beer. These include the removal of solids during fermentation and the presence of ethanol and of lactic acid in the final brew. 8. In order to reproduce the way in which beer is brewed domestically in Fe containers, a study was done in which beer was prepared in the presence of Fe wire. Under such circumstances Fe was rapidly dissolved and the final Fe concentration of the brew was 89 mg/l. However, the nature of the Fe-containing compound or compounds was not elucidated.