Dairy fats cut colon cancer risk

A diet high in dairy products dramatically reduces the risk of colon cancer, the third most lethal type of cancer, a Swedish study finds. The catch: To have the effect, these foods must be rich in fat, the component that nutritionists have been trying to pull out of whole milk and other foods for years.

Previous studies of the protective effect of dairy foods against colon cancer had shown that calcium was a factor, but not the only one. Susanna C. Larsson and her colleagues at the Karolinska Institute in Stockholm decided to examine trace fats in dairy products with purported anticancer activity.

They correlated 14 years of dairy-consumption data and colorectal cancer incidence in nearly 61,000 women. In the October American Journal of Clinical Nutrition, the team reports that for every additional two servings of high-fat dairy products a woman ate on average per day, her colorectal cancer risk fell by 13 percent. The benefit was especially pronounced for cancer in the colon region leading into the rectum. Each additional two servings of high-fat dairy goods consumed daily reduced risk of cancer at this site by 34 percent.

Larsson says that although her team had anticipated that conjugated linoleic acid—an unusual trans fat possessing anticancer properties (SN: 3/3/01, p. 136: The Good Trans Fat)—would explain the advantage of the high-fat dairy diet, the new data now largely discount that.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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