COLUMBUS, Ohio—Preclinical evidence of the preventive benefits of omega-3 polyunsaturated fatty acids (PUFAs) in breast cancer continues to fuel interest in the potential role of dietary fat content in reducing breast cancer risk. A six-month, randomized open-label study of 48 women with increased breast cancer risk received 1, 3, 6 or 9 capsules/d of an omega-3 PUFA supplement that provided 0.84, 2.52, 5.04 and 7.56 g/d docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA) , respectively (Am J Clin Nutr. 2010;91(5):1185-94). Subjects made monthly visits, at which time pill counts were made and fasting blood samples were collected to determine fatty acid profiles; anthropometric measurements were made, breast adipose tissue samples were collected, and laboratory tests of toxicity (alanine aminotransferase, low-density lipoprotein (LDL) cholesterol and platelet function) were made at baseline and at three and six months.
All doses led to increased serum and breast adipose tissue EPA and DHA concentrations, but the response to 0.84 g DHA+EPA/d was less than the maximum possible response with 2.52 g/d. Body mass index (BMI) attenuated the dose response for serum tissue DHA and EPA and breast adipose tissue DHA in all of the treatment groups. The incremental increase in DHA and EPA correlated inversely with baseline fat and serum values. Compliance over six months was 92.9 ± 9.2 percent and was unaffected by treatment arm. No severe or serious toxicities were reported. In conclusion, daily doses up to 7.56 g DHA+EPA were well tolerated with excellent compliance. BMI and baseline fatty acid concentrations modulated the dose-response effects of omega-3 PUFA supplements on serum EPA and DHA and breast adipose tissue DHA.
