Effect of corn lectins on the intestinal transport of trace elements

The absorption of iron, copper, zinc, and cobalt deriving from the diet and supplements varies, depending on the form of these trace elements and the presence of absorption inhibitors. The objective of this study was to examine the absorption of iron, copper, zinc, and cobalt in the presence of corn lectin as a possible inhibitor of intestinal absorption. The highest level of inhibition was shown in bull in vitro intestinal segments: incubation with corn lectins reduced the absorption of copper by 35.5%, of zinc by 28%, and of cobalt by 17.3%. It caused no observable effect on iron absorption. The addition of N-acetylgalactosamine neutralised the inhibitory effect of corn lectins and restored the absorption of the trace elements. The levels of copper and iron in the blood of rats receiving a diet supplemented with lyophilized corn lectins, decreased by 11.3% and 16.4%, respectively. Our results thus suggest that corn lectins may act as absorption inhibitors of iron, copper, zinc, and cobalt, most likely through blocking the transport of elements across the apical membrane of enterocytes. The present study suggests that individuals should consider their trace element status if their diet includes high amounts of raw corn. However, additional in vivo studies are required to confirm these results.