Assessment of iron bioavailability from different bread making processes using an in vitro intestinal cell model

Myo-inositol hexakisphosphate (IP6), is the main iron chelator in cereals and bread. The aim of this study was to investigate the effect of three commercial baking processes (sourdough, conventional yeast and Chorleywood Bread Making Process (CBP)) on the IP6 content of wholemeal bread, its impact on iron uptake in Caco-2 cells and the predicted bioavailability of iron from these breads with added iron, simulating a mixed-meal. The sourdough process fully degraded IP6 whilst the CBP and conventional processes reduced it by 75% compared with wholemeal flour. The iron released in solution after a simulated digestion was 8-fold higher in sourdough bread than with others but no difference in cellular iron uptake was observed. Additionally, when iron was added to the different breads digestions only sourdough bread elicited a significant ferritin response in Caco-2 cells (4.8-fold compared to the other breads) suggesting that sourdough bread could contribute towards improved iron nutrition

Estimation of the iron bioavailability in green vegetables using an in vitro digestion/Caco-2 cell model

It is estimated that over 30% of the global population is anaemic, half of which is due to iron deficiency. The bioavailability of iron from vegetables is low and variable, and influenced by food composition and matrix. We have therefore determined the relative bioavailability of iron in five types of green vegetable, spinach, broccoli, savoy cabbage, curly kale and green pepper, by measuring the ferritin response in a simulated digestion/Caco-2 cell model. Savoy cabbage gave the highest ferritin response and analysis of the digest showed that the iron was present in low molecular weight fractions which contained glucose, fructose, organic acids and amino acids. The addition of fructose 1,6-biphosphate to the Caco-2 cells increased iron uptake 2-fold. These results demonstrate that cabbage was the best source of bioavailable iron out of the vegetables studied and suggest that the formation of complexes with fructose derivatives contribute to increase the iron bioavailability