Diet tied to breast and ovarian cancer risks

NEW YORK (Reuters Health) - A new study suggests that women who eat diets rich in meat and dairy may have a decreased risk of breast cancer, while those who bulk up on fiber, fruits and vegetables show a lower risk of ovarian cancer.

The findings, published in the International Journal of Cancer, add to questions surrounding the role of diet in women's risk of the cancers.

High alcohol intake has been consistently linked to breast cancer risk, but when it comes to other facets of the diet, studies have yielded conflicting results, according to the researchers on the current work, led by Dr. Valeria Edefonti of the University of Milan.

Some studies, for example, have found that women who eat a lot of red and processed meat are more likely to develop breast cancer than other women; but other studies have found no such link. Saturated fat, found mainly in animal products, has been tied to higher breast cancer risk in some studies, but not in others.

While many of these studies have looked at single nutrients or food groups, another way to address the question is to look at dietary patterns -- the combination of nutrients and foods that a person tends to favor.

For their study, Edefonti and her colleagues assessed dietary patterns among 3,600 women with either breast or ovarian cancer, and 3,413 healthy women of the same age.

Using detailed dietary questionnaires, the researchers identified four common dietary patterns in the study group: an "animal product" pattern, which was heavy in meat and saturated fat, but also zinc, calcium and certain other nutrients; a "vitamins and fiber" pattern, which besides fiber was rich in vitamin C, beta-carotene and other nutrients found in fruits and vegetables; an "unsaturated fat" pattern that contained high amounts of vegetable and fish oils, as well as vitamin E; and a "starch-rich" pattern high in simple carbohydrates, vegetable protein and sodium.

Overall, the study found, women who followed a pattern rich in vitamins and fiber had a 23 percent lower risk of ovarian cancer than women who consumed the lowest amounts of those foods and nutrients.

On the other hand, the animal-product pattern was linked to a similar reduction in breast cancer risk.

Women who followed the unsaturated-fat pattern had a slightly reduced risk of breast cancer, while the starch-rich diet was tied to elevated risks of both cancers.

It's not yet clear what to make of the findings, in part because they show associations between dietary patterns and cancer risk -- and not that the foods directly affect cancer development.

In terms of general health, experts usually recommend limiting red meat and saturated fat, while eating more fruits, vegetables, whole grains and sources of "good" unsaturated fat -- like fish, nuts and olive oil.

SOURCE: International Journal of Cancer, February 2008.