The nutritional toxicity of Phaseolus vulgaris lectins.

In rats fed on beans (Phaseolus vulgaris) the poorly digestible lectins were shown to react with intestinal cells in vivo and to cause a disruption of many of the brush borders of duodenal and jejunal enterocytes. Although depressed to a certain extent, absorption still occurred, probably through the non-disrupted cells of the small intestine. In addition, abnormal absorption of potentially harmful substances, lectin-related or of bacterial origin, could also occur, possibly as a direct effect of the disruption caused by the lectins on the enterocytes. It is suggested that toxicity was the result of ensuing systemic effects, such as for example the observed high N excretion possibly through increased tissue catabolism.