Omega-3 Fatty Acids and Breast Cancer – Is There a Connection?

Omega-3 fatty acids are polyunsaturated fatty acids that are essential for health and necessary for many functions in the body. Because they’re not produced in our bodies, they must be acquired through supplements and/or diet. Some dietary sources of omega-3s include: salmon, sardines, tuna, mackerel, trout, and flax. The metabolism of omega-3 fatty acids produces anti-inflammatory by-products, in contrast to the metabolism of omega-6 fatty acids, which produces pro-inflammatory by-products. Research on omega-3 fatty acids suggest they may play a role in lowering blood pressure, cholesterol and triglycerides, as well as reducing an abnormal heart rhythm.

But can omega-3 fatty acids help prevent breast cancer?

According to recent research, omega-3 fatty acids may very well lower the risk for breast cancer. A study published in the Journal of Nutritional Biochemistry in 2013 has shown, using a genetic approach, that the development of mammary tumors is directly blocked by omega-3 fatty acids. The anti-cancer effect of omega-3 fatty acids was tested in mice. Mice with the fat-1 transgene were used. These mice are able to synthesize omega-3 fatty acids in the body from omega-6 fatty acids acquired through the diet. Mice with (MMTV)-neu(ndl)-YD5, an aggressive mammary tumor virus, were also used (mammary tumors in mice correspond to breast tumors in humans). This mouse mammary tumor allows us to model human breast tumors that bear the HER-2 gene (breast cancer which bears the HER-2 gene is treated with the drug Herceptin). Researchers bred the fat-1 mice with the (MMTV)-neu(ndl)-YD5 mice, which led to offspring mice that produced omega-3 fatty acids and also developed mammary tumors. Three groups of mice were then evaluated over 20 weeks to see how quickly tumors grew, and to assess the volume, number of tumors, and growth rate: MMTV-only mice (control), MMTV/fat-1, and MMTV mice on an omega-3 diet.

The results of the study in terms of tumor size showed that total tumor volume in MMTV/fat-1 mice, which manufactured omega-3 fats from omega-6 fats, was significantly less than in MMTV-only mice. There was a 30% difference in final tumor volume between the groups. A similar effect was seen in in the MMTV mice on an omega-3 diet and the MMTV-only mice. Also, total tumor volume in MMTV-mice on an omega-3 diet was significantly less than MMTV/fat-1 mice, showing the power of an omega-3 rich diet. There was no significant difference in the number of tumors that mice developed between the MMTV/fat-1 mice and MMTV mice on an omega-3 diet, and both groups had significantly fewer tumors than MMTV control mice.

These results demonstrate that both the group with genes that produced omega-3 fatty acids (MMTV/fat-1) and the dietary group (MMTV on omega-3 diet) had a decreased size and a smaller number of tumors than control mice. Both groups exposed to omega-3 fatty acids thus had a significant decrease in tumor development. The fact that this was seen in mice that bore the HER-2 gene suggests that these results are especially relevant for patients who have HER-2 positive breast cancer. Whether they are obtained through diet or through taking fish oil supplements, it appears that omega-3 fatty acids have a real potential to improve the health of breast cancer patients.