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Does Omega-3 Fats Display Anti-Breast Cancer Effects?

by Dr. Jamesh Meschino on

December 18, 2023 in

Source: Journal of Biochemistry (December 2017)
Nutrition / Natural Medicine Update (January 29, 2018)

Over many years we have seen studies suggesting that omega-3 fats can help prevent various types of cancer. Human observational studies have shown this (Epidemiological studies), as well experimental studies with animals. 

Omega-3 fats are converted by the cells of the body into mini-hormones called prostaglandin series-3 (PG-3). Once formed in the cell, PG-3 slows down the rate of cell division, which in turn, decreases the risk of cancer. 

When cells divide too fast they tend to make genetic mistakes in their DNA replication that can result in cancerous mutations. So, it’s always better to have a slower cellular replication rate. 

Omega-3 fats have also been shown to lengthen telomeres, which are the small pieces of DNA at the tips of the DNA chain within the cell. With each cell division telomeres get shorter, and once at a critical point of telomere shortening cells are much more prone to undergo transformation into cancer cells. 

So, re-lengthening telomeres is another way that omega-3 fats have been shown to reduce cancer risk.

The thing to know is that there are three different omega-3 fats found in foods. Flaxseed oil, for instance, is 58% omega-3 fat content. These plant-based omega- 3 fats are slightly different from the two omega-3 fats found in fish and fish oil. 

Plant-based omega-3 fats contain ALA (alpha-linolenic acid) and fish oil contains EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid, respectively). The body can slowly convert ALA (from flaxseed oil and other plant sources) into EPA. 

We know that it’s EPA that gets converted into PG-3, which slows down cellular replication, and it’s EPA that lengthens telomeres. 

Is fish oil superior to flaxseed oil?

Most often we come across the question, is EPA-containing fish oil superior to ALA-containing flaxseed oil, with respect to cancer prevention.The  researchers at the University Guelph chose to investigate such question, and they published the results of their study in the Journal of Biochemistry in December of 2017.

This study was the first to compare the cancer-fighting potency of plant-based omega-3 fats to that of fish oil omega-3 fats, on breast tumor development. The study involved feeding the different types of omega-3 fats to mice who had a highly aggressive form of human breast cancer called HER-2. 

HER-2 mutations are present in 25 percent of women with breast cancer and have a poor prognosis. Researchers exposed these mice to either the plant-based or fish oil-based omega-3 fats, beginning in utero.

The results showed that, overall, exposure to fish oil-based omega-3 fats reduced the size of the tumors by 60 to 70 percent and the number of tumors by 30 percent. However, plant-based omega-3 fats produced the same result provided higher doses were used.

The researchers stated, “Omega-3s prevent and fight cancer by turning on genes associated with the immune system and blocking tumor growth pathways.” 

“It seems EPA and DHA are more effective at this. In North America, we don’t get enough omega-3s from fish and seafood, so there lies an opportunity to improve our diet and help prevent the risk of breast cancer.” 

What is the recommended dosage?

Based on the dosages given in the study, one of the researchers commented that humans should consume two to three servings of fish a week to have the same preventive effect. 

It appears that plant-based sources of omega-3 fats are also beneficial, especially in the form of flaxseed oil, in my opinion. I routinely take an essential fatty acid supplement each day that contains fish oil, flaxseed oil, and borage seed oil. 

The borage seed oil helps to increase synthesis of Prostaglandin series-1 (PG-1), which has been shown to help decrease inflammation and may have some cancer prevention properties as well.

I have included a link to the research study in the text below


Jiajie Liu, Salma A. Abdelmagid, Christopher J. Pinelli, Jennifer M. Monk, Danyelle M. Liddle, Lyn M. Hillyer, Barbora Hucik, Anjali Silva, Sanjeena Subedi, Geoffrey A. Wood, Lindsay E. Robinson, William J. Muller, David W.L. Ma. Marine fish oil is more potent than plant-based n-3 polyunsaturated fatty acids in the prevention of mammary tumours. The Journal of Nutritional Biochemistry, 2017

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Dr. Meschino

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Dr. James Meschino