Until recently the study of nutrition has been regarded, at best, as a specialist area of biomedical research but more often has been categorized as fringe faddism. However, nutrition is now beginning to emerge as a credible science and a weighty body of evidence now suggests that the immune system is influenced substantially by the type and quantity of ingested food (for review see Ref. 10). Perhaps the most dramatic and best recognized example of the effects of diet on the immune system is that of protein-calorie malnutrition (12). Particularly common in the third world, afflicted individuals are very much susceptible to infection by all classes of microorganisms. If a balanced diet is made available, normal immune function is restored. Over the last decade data has accumulated from both experimental and clinical studies to convincingly implicate diet in having a substantial role in the manifestation and progression of autoimmune disorders. Autoimmune diseases comprise a diverse group of syndromes of unknown etiology but with genetic, viral, and environmental factors being implicated in their pathogenesis. The majority of investigations, however, have centered on animals systems because of the obvious difficulties associated with human experimentation (11). Without doubt, of greatest significance has been the derivation of several murine models, notably the New Zealand (the NZB and NZB/W) and MRL/ lpr strains which develop, spontaneously, immunopathological abnormalities similar to human autoimmune syndromes (21). Autoimmune diseases comprise a diverse group of syndromes of unknown etiology but with genetic, viral, and environmental factors being implicated in their pathogenesis. Since the observations by Fernandes and colleagues over a decade ago, (8) that either a reduced intake of calories, fat, or protein could delay immune complex nephritis and hemolytic anemia in New Zealand mice, virtually all classes of macroand micronutrients have been shown to be able to modulate a variety of autoimmune disorders.