Biomarkers of fatty acid exposure and breast cancer risk

Study of the effects of most individual biologically active dietary fatty acids on human disease requires the use of biomarkers of long-term intake in well-designed epidemiologic studies. Several small studies of tissue taken from women undergoing surgery for breast abnormalities have compared fatty acid profiles of women with ascertained metastatic breast cancer with those with other abnormalities. These studies, although often flawed in design and generally of inadequate statistical power to determine significant differences, provide some evidence. Human studies are generally consistent with animal models suggesting a protective effect of n-3 fatty acids, a detrimental effect of high n-6 fatty acids, and the possible importance of the ratio of these two classes of dietary fatty acids on both breast cancer incidence and recurrence. High intakes of monounsaturated fatty acid were also often negatively associated with breast cancer. The effects of trans fatty acids have rarely been studied, but there are some indications that they may enhance risk. In general, the study of individual fatty acids is in its infancy. Larger well-designed studies with diverse population and modern analyses of individual fatty acids are needed.