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Lack of omega-3 increases your risk of breast cancer

- but fish oil helps as prevention

Lack of omega-3 increases your risk of breast cancerBreast cancer is the number one cause of cancer-related deaths among women worldwide. The diet has huge importance and according to a new Polish study, eating more fish with omega-3 fatty acids may help lower the risk of developing the disease. The study supports earlier research by showing that in order to prevent breast cancer, it is vital to consume plenty of omega-3. The best sources of these essential fatty acids are oily fish and fish oil supplements. The preventive effect of omega-3 is increased additionally if you also get plenty of vitamin D and selenium.

Far more women in Northern Europe, the United States, and Canada get breast cancer compared with women in Asia and Africa. This is primarily down to differences in diet and lifestyle. In fact, if an Asian or African woman moves to Europe or the USA her risk goes up. Although some women are genetically predisposed it is often potentially harmful factors in our diet and lifestyle that trigger breast cancer. It takes several years for breast cancer to develop so it is highly relevant to look at ways to prevent the disease. Simple dietary changes, possibly combined with nutritional supplements, seem to have a positive effect.

Dietary fats, oily fish, and weight control lowers the risk of breast cancer

According to the Polish researchers that have published the new breast cancer study, it is important to look at risk factors such as the diet. Simple adjustments are an inexpensive and useful way to prevent the disease without the need for pharmaceutical drugs. The whole purpose with the study was to investigate how different types of fat in the diet and fish consumption affected the rate of breast cancer among women.
A total of 201 Polish women with an average age of 58 years took part in the trial. All participants had been diagnosed with breast cancer. Meanwhile, a group of 201 healthy female peers served as a control group. The scientists used a standardized food questionnaire and interviews to map out the eating habits and lifestyle of all participants. They observed that the women with the highest consumption of dietary fat and whose fat intake represented more than 10 percent of the total energy intake had a significantly lower risk of getting breast cancer compared with the women that ate very little fat. The women that hardly ever ate fish and were overweight had a greater risk of breast cancer than the women who were slim and ate more fish.
Based on their observations, the scientists concluded that a relatively high intake of dietary fat lowers the risk of breast cancer, especially when it comes to the omega-3 fatty acids that are found in oily fish. Their study is published in the science journal In Vivo.

The important balance between omega-3 and omega-6

Both omega-3 and omega-6 are essential fatty acids that are found in all our cell membranes where they control a host of different biochemical processes. It is extremely important to have the right balance between the two fatty acids. Consuming too much omega-6 and/or too little omega-3 sets the stage for chronic inflammation that can speed up the development of different cancer forms.
For instance, an American study conducted on mice revealed that a diet with great amounts of omega-3 fatty acids significantly lowered the risk of injected breast cancer cells attaching to the mammary glands of the mice. At the same time the risk of the cancer cells spreading to other organs was lower in the group of mice that got a diet with plenty of omega-3 and they even lived longer than the mice that were fed a diet with a lot of omega-6.
Furthermore, there were mice in the omega-3 group that did not develop breast cancer. It appeared that they were able to destroy the breast cancer cells that had been injected. The mice in the omega-3 group had much less inflammation. The scientists explain that omega-3 helps suppress the type of inflammation that can trigger fast development and rapid proliferation of tumors.
The study is published in Clinical and Experimental Metastasis.

Omega-3 fatty acids inhibit inflammation in collaboration with vitamin D and selenium

The results of these two studies support earlier research where scientists have demonstrated that fish oil intake during pregnancy and in childhood helps suppress the development and proliferation of breast cancer cells later in life.
However, eating a diet with lots of omega-3 or taking fish oil is not enough to prevent breast cancer. Other studies show that vitamin D and selenium yeast in particular play a significant role. Both vitamin D and selenium strengthen the immune defense and counteract undesirable inflammation.

These factors increase the risk of breast cancer

  • Hormone-disrupting substances in the environment
  • Excessive levels of estradiol (a form of estrogen)
  • Overweight (it increases the estrogen production in fat tissue)
  • Hormone therapy after menopause (preparations with estradiol)
  • Birth control pills and hormonal coils (slightly increased risk)
  • Alcohol causes nearly 3% of all breast cancers in Europe, especially in Denmark because Danish women drink more
  • Ionizing radiation
  • Chronic inflammation
  • Lack of sleep
  • Lack of omega-3 fatty acids, vitamin D and selenium


Dorota Dydjow-Bendek and Pawel Zagozdzon. Total Dietary, Fatty Acids, and omega-3/omega-6 Ratio as Risk Factors of Breast Cancer in the Polish Population – a Case-Control study. In Vivo January-February 2020

Sarawoti Khadge et al. Long-chain omega-3 polyunsaturated fatty acids decrease mammary tumor growth, multiorgan metastases and enhance survival. Clin Exp Metastasis. 2018

Machado MRM, de Sousa Almeida-Filho B et al. Low pretreatment serum concentration of vitamin D at breast cancer diagnosis in postmenopausal women. Menopause September 17, 2018

University of California – San Diego. Greater Levels of vitamin D associated with decreasing risk of breast cancer. June 15, 2018

Clark LC et al: Effects of Selenium Supplementation for Cancer Prevention in Patients with Carcinoma of the Skin. Journal of the American Medical Association: 1996.

Harris HR, et al. Selenium intake and breast cancer mortality in a cohort of Swedish women. Breast Cancer Res Treat. 2012.

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