Are there any dietary measures that protect against breast cancer? I have heard -fat diet reduces the likelihood of developing breast cancer.
One of the early reasons to suspect that a low-fat diet might prevent breast cancer was the finding that the number of breast cancers is about five times greater in countries where people consume a high-fat diet than in those countries where fat intake is low. And over the years, a number of newspaper stories and magazine articles have described studies concluding that a low-fat diet decreases breast cancer risk. These studies involved relatively few subjects, however, and other research found no relationship.
A report in the Feb. 8 issue of the New England Journal of Medicine re-examined the issue by pooling results of seven different prospective studies involving about 338,000 women for up to seven years in four countries. The results failed to show any link between breast cancer risk and either total calories or fat in the diet. There was no reduction in the risk of breast cancer even among those women who consumed less than 20 percent of their calories as fat (the average fat intake in this country is about 37 percent of total calories). In fact, those women who consumed less than 15 percent of their calories as fat had a small, but significant, increase in breast cancer incidence. This study further found no link between breast cancer and any specific type of fat.
Although postmenopausal women have been thought to be at the greatest risk for breast cancer from a high-fat diet, a separate analysis of the data for these women also showed no relationship between fat intake and breast cancer. These results make it highly unlikely that a reduced-fat diet in middle-age and older women (the range of those in these studies) will reduce breast cancer risk, but it is possible that breast cancer incidence would be decreased if children, adolescents and younger women ate a low-fat diet.
In contrast to this lack of support for a relationship between a high fat intake and breast cancer, more than 30 studies have shown that women who have more than one alcoholic drink a day face about a 50 percent increase in their risk of breast cancer.
Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.
Pub Date: 5/21/96