Recommendation 8 Background

The AICR/WCRF panel concludes, There is a consistent pattern, suggesting that diets high in total fat possibly increase the risk of lung, colorectal, breast and prostate cancers, and that diets high in animal fat and/or saturated fat possibly increase the risk of lung, colorectal, breast, endometrial and prostate cancers. The panel also states that diets high in cholesterol possibly

increase the risk of lung and pancreatic cancers.

The following table summarizes fat, cholesterol and the risk of cancer based on the scientific evidence examined by the AICR/WCRF.

Fat, Cholesterol and Cancer

Evidence No relationship Increases risk
Convincing    
Probable Cholesterol
  • Breast
  
Possible Monounsaturated fat
  • Breast

Polyunsaturated/vegetable fat

  • Breast
 Total fat
  • Lung
  • Colon, rectum
  • Breast
  • Prostate

Saturated/animal fat

  • Lung
  • Colon, rectum
  • Breast
  • Endometrium
  • Prostate

Cholesterol

  • Lung
  • Pancreas
Insufficient   Total fat
  • Ovary
  • Endometrium
  • Bladder

Saturated/animal fat

  • Ovary

Cholesterol

  • Endometrium

Adapted from Food, Nutrition and the Prevention of Cancer: a Global Perspective, 1997.

 

The panel feels that there is convincing evidence for increased risk of cancer of the endometrium, probable evidence for post-menopausal breast cancer and possible evidence for colon cancer by obesity.

 

What is the relation of high-fat diets to obesity? There was disagreement among the panel members as to whether diets high in fat increase the risk of obesity. And it was felt that the emphasis on reducing total fat intake might distract from other important preventive strategies such as increased physical activity. Food products have been developed around this idea of low fat. However, they are carbohydrates high in calories with low nutritional value. In other words, they are high in refined flour, sugar and low in vitamins and minerals. An emphasis on low fat may lead some to avoid healthy foods with a moderate to high fat content. This would be the case of salads with oil dressings, or vegetables sautéed in vegetable oil or soy bean products.

High carbohydrate, low fat diets are consumed in many developing countries, but those populations are lean and physically active. In addition, it is

unknown how poverty, food availability and physical activity interact with the diet.

Carefully controlled metabolic studies have shown that unsaturated fats replaced by carbohydrate reduce blood levels of HDL cholesterol and increase triglycerides without reducing total or LDL cholesterol. This atherogenic lipid pattern is seen among nonobese people with activity patterns typical of urbanized populations.

The following point has been made in defense of the recommendation to limit consumption of fatty foods. While low fat diets often fail to control or reverse obesity, this is no evidence that the initial accumulation of adipose tissue is not promoted by a high fat diet. Adipose tissue is gained readily for survival and the new homeostasis is defended. Attempts to loose weight result in metabolic and behavioral responses to defend the existing weight.

For practical applications see Recommendation 8 "How to"

BACK TO FOURTEEN RECOMMENDATIONS

EXTOXNET FAQS Diet and Cancer Homepage

Prepared 1998 by Bernadene Magnuson, Ph.D.
University of Idaho, Dept. of Food Science and Toxicology - EXTOXNET FAQ Team.