Immunological aspects of the potential role of dietary carbohydrates and lectins in human health

Background: Little is known regarding the immunobiology of dietary carbohyd rate intake and its relevance to human health, although foodstuffs contain many simple and complex carbohydrates. Synopsis: Lectins, immunoglobulins, viruses, bacteria and host cells intera ct with each other forming a delicate equilibrium within the alimentary can al which may be perturbed by saccharide intake. The ways in which these com ponents may interact at different sites within the alimentary canal are dis cussed, as are the possible influences on mucosal immunity and the inductio n of oral tolerance. The possible systemic influences of absorbed saccharid es at loci remote from the gut are considered in terms of inhibition of die tary and endogenous lectins, inhibition of bacterial attachment, and altera tion of leukocyte homing behaviour. Finally, possible means by which dietar y carbohydrates might modify various specific diseases are considered. Conclusions: It is probable that dietary carbohydrates can alter the equili bria between lectins, secretory IgA and micro-organisms in the alimentary c anal, and this consideration could be exploited to promote health. The poss ible effects of dietary saccharides on allergy/oral tolerance or on recogni tion events at gut-remote sites warrant further investigation.