The Journal of Nutrition Vol. 127 No. 5 May 1997, pp. 830S-833S
Copyright ©1997 by the American Society for Nutritional Sciences

Importance of Sphingolipids and Inhibitors of Sphingolipid Metabolism as Components of Animal Diets

Alfred H. Merrill Jr., Eva-Maria Schmelz, Elaine Wang, Dirck L. Dillehay^*, Larry G. Rice, Filmore Meredith^**, and Ronald T. Riley^**

Departments of Biochemistry and ^* Pathology, Center for Nutrition and Health Sciences and ^* Division of Animal Resources, Emory University School of Medicine, Atlanta, GA 30322-3050;  USDA-ARS, Ames, IA 50010, and ^** Toxicology and Mycotoxins Research Unit, USDA-ARS, Athens, GA 30613

Sphingolipids are highly bioactive compounds that participate in the regulation of cell growth, differentiation, diverse cell functions, and apoptosis. They are present in both plant and animal foods in appreciable amounts, but little is known about their nutritional significance. Recent studies have shown that feeding sphingomyelin to female CF1 mice treated with a colon carcinogen (1,2-dimethylhydrazine) reduced the number of aberrant colonic crypt foci; longer-term feeding also affected the appearance of colonic adenocarcinomas. Therefore, dietary sphingolipids should be considered in studies of the relationships between diet and cancer. Sphingolipids have also surfaced as important factors in understanding the mechanism of action of a recently discovered family of mycotoxins, termed fumonisins. Fumonisins are produced by fungi commonly found on maize and a few related foods, and their consumption can result in equine leukoencephalomalacia, porcine pulmonary edema and a number of other diseases of veterinary animals and, perhaps, humans. A cellular target of fumonisins is the enzyme ceramide synthase, and disruption of sphingolipid metabolism by fumonisins has been established by studies with both cells in culture and animals that have consumed these toxic mycotoxins. These findings underscore the ways in which sphingolipids and agents that affect sphingolipid utilization should be given consideration in selecting animal diets for nutritional and toxicological studies.