Over the years there has been much debate and controversy regarding the protective effects of omega-3 and possibly omega-6 fats on cancer prevention. The large UK Biobank Study has shone a light on this subject that appears to be very important. In following over 250,000 subjects during an average follow-up period of almost 13 years, the study showed that individuals with higher blood levels of omega-6 and omega-3 fats had a moderately lower risk of developing cancer at 19 different tissue sites, than individuals who had lower levels of these fats in their blood. More specifically, participants with higher levels of omega-3s had lower rates of colon, stomach and lung cancer, in addition to lower rates of other digestive tract cancers. High omega-6 levels led to lower rates of 14 different cancers, including brain, malignant melanoma, bladder cancer and some others. The take home message is that consuming more fish, fish oil, and flaxseed oil is likely to be advantageous due to the presence of omega-3 fats. But so true is the intake of certain plant and seed oils that contain omega-6 fats, such as borage seed oil, as well as olive oil, canola oil, corn oil, sunflower seed oil, safflower oil, and avocado oil.

In the past there has been some evidence that too much omega-6 fat intake may promote inflammation, cancer and heart disease, so I usually advise patients to use extra virgin olive oil and avocado oil, as their main oils and maybe grapeseed oil if cooking to higher temperatures. I also think that taking a supplement each day that contain fish oil, flaxseed oil and borage seed oil is a smart prevention strategy for many reasons. The Biobank study did show that higher blood levels of omega-3 fats was associated with a small increase in prostate cancer, but many other studies have shown that omega-3 fats help to guard against prostate cancer to some degree.  In fact, as stated in the journal of Molecular Medicine, omega- 3 fats do not increase prostate cancer risk and are associated with a decrease in prostate cancer mortality (reference 4 below). So, I wouldn’t be too alarmed about the risk of omega-3 fats and prostate cancer. There are many ways to protect your prostate gland from enlargement and cancerous changes that go way beyond any involvement of omega 3 or omega -6 fats.

I have provided a link to the UK Biobank Study in the text below as well as some other references of interest on this subject.

References:

Zhang Y, et al. Association of plasma omega-6 and omega-3 fatty acids with overall and 19-site-specific cancers: a population-based cohort study in UK Biobank. Int J Cancer. 2024 (Oct 17). https://pubmed.ncbi.nlm.nih.gov/38343844/

Health Effects of Omega – 6 Fats (Mount Sinai)

https://www.mountsinai.org/health-library/supplement/omega-6-fatty-acids#:~:text=Omega%2D6%20fatty%20acids%20can,supplements%20are%20usually%20not%20necessary.

Higher levels of omega-3, omega-6 may protect against cancer. Science Direct (Nov 4, 2024) https://www.sciencedaily.com/releases/2024/11/241104112234.htm

DiNicolantonio J.J., et al. Do omega-3 fatty acids cause prostate cancer? Molecular Medicine, 2013, 110 (4): 293-295. https://pmc.ncbi.nlm.nih.gov/articles/PMC6179880/#:~:text=A%20more%20thorough%20overview%20of,sudden%20death%20and%20CV%20events.

Eat Smart, Live Well, Look Great,
Dr. Meschino