Iron deficiency is due not only to a lower intake of this essential trace metal, but often to poor availability of dietary iron. It hu been suggested that the uptake of iron from the intestinal lumen into enterocytes may be the rate-limiting step for absorption of this micronutrient. lt is known that Maillard reaction products, formed during the storage and beat treatmeot of foods, may complex iron and influence its speciation in the intestinal lumen, thereby affecting the uptake by the enterocyte. The use of a Caco-2 cell model has been demonst:rated as a physiological means of measuring mucosal cell iron uptake; moreover, the usefulness of Caco-2 cells has been shown in assessing human iron absorption and determining food iron availability. In the present study, equimolar mixtures of Glucose-Lysine and Glucose-Methionine (40% w/w moisture) were prepared, and were assayed raw (LG and MG) or heated at 150°C for either 30 (LG30 and MG30) or 60 min (LG60 and MG60). Monolayers of Caco-2 cells seeded into Petri dishes (to examine Fe uptake) and bicameral chambers (to examine Fe transport) were exposed for 4h to solutions 0.5mM Fe, containing the different samples. The iron content of the solutions and colls was measured by atomic absorption spectrophotmetry; bovine liver (CRM 185) was used as an externa) control the Fe uptake in the Caco-2 cells seeded in the presence of the glucose-amino acid mixtures, raw or heated, when compared with the Fe uptake from the no added-samples solution (DMEM), more markedly with GM samples. The heat treatment of GL samples, 30 or 60 min, did not affect the resut with GM samples a decreased Fe uptake was observed only in GM60. The percentage of Fe transferred across the Caco-2 monolayer increased in the presence of GL samples compared with the Fe transported from DMEM, except in GL30. However, the Fe transported to the basolateral chamber was not affected by GM samples. In summary, although the bibliography describes a positive influence of lysine on iron uptake, we only found this effect on Fe transport, but not on Fe uptake by Caco-2 cells. The presence of methionine samples impaired the Fe uptake, and had no effect on Fe transport.

Resumen del trabajo presentado al 1st International FESTEM Symposium on Trace Elements in Medicine and Biology, celebrado en Venecia (Italia) del 16 al 19 de mayo de 2001.

Peer reviewed