The effect of dietary fat on tumor growth

Experiments in animals have shown that high-fat diets can enhance tumor growth. Animals receiving high-fat diets routinely ingest up to 5 times the level of fat (by weight) found in standard chow diets. Rats given oil by gavage can triple caloric intake from fat compared to untreated controls. In laboratory animals, high-fat diets appear to play a role during the postinitiation phase of tumorigenesis. The type, level, and nature of the dietary fat may also affect the outcome of bioassays. Fat does not initiate the tumorigenic process. Additional factors must be considered when studying and interpreting the effects of dietary fat. Animal diets and dietary fats should be protected against oxidation. Antioxidants protect against oxidation but may also modify the tumorigenic process. Adequate levels of essential fatty acids must be provided. Dietary fat level can alter nutrient density and palatability; each of these factors can affect nutrient intake which can in turn influence metabolic processes.