Fat Consumption
Does fat intake affect the risk of breast cancer?
No. Body fat affects the risk of breast cancer. Dietary intake of fat does not. Women who eat high-fat diets develop breast cancer at the same rate as those who eat low-fat diets. There is no difference in breast cancer rates that is related to total fat or saturated fat consumption. Some evidence indicates that polyunsaturated fats can promote breast cancer in women, just as they do in laboratory animals. An increased intake of monounsaturated fats (from olive oil, canola oil, soy protein, nuts, and other sources) appears to lower the risk of breast cancer, although the evidence is not consistent.
Why did researchers think that fat intake was related to the rate of breast cancer?
In countries where total fat consumption is low, the rates for breast cancer are frequently low. In countries where fat consumption is high, the rates are often high. Laboratory rats fed high-fat diets develop breast tumors more often after being exposed to carcinogens. Because of this apparent connection, many research studies were designed to see if the rates of breast cancer for women within a single country were different according to the amount of fat in their diet. Now that the results of many large studies have been published, the answer is clear: total fat consumption does not affect the risk of breast cancer.
Although it is possible to find one or more studies reporting that high total fat consumption is associated with a modest increase in the risk of breast cancer, there are just as many that report a modest reduction in risk. By combining all of the studies, the experience of over 2 million woman-years of observation should be able to identify even small differences in the risk of breast cancer that would relate to fat intake: such analyses showed no differences.
