Role of Dietary Fat in Ultraviolet Light–Induced Carcinogenic Expression

Abstract

The indictment of fat as a dietary constituent that potentiates carcinogenesis arose from a study of Watson and Mellanby in 1930 [1]. Animal diets containing high levels of butterfat (12.5-25%) were shown to enhance coal tar-induced skin tumor formation. After this seminal observation, intense investigations of the effects of dietary fat on chemically-induced carcinogenesis were conducted during the 1930s through the 1950s. There were several conclusions from these studies that are noteworthy [2]. These, however, must be tempered by the fact that many of these early studies failed to control for major dietary parameters, e.g., caloric density. And although much of the exacerbation of fat on tumor formation reported in these early studies could be explained on the basis of increased caloric intake, fat, per se, increased the rate of tumor formation, particularly when total caloric intake was restricted. Also, much of the exacerbation by fat on tumor formation occurred during the post initiation stage of carcinogenesis.