The foods we eat play a crucial role in our health. In my new book, The Gene Therapy Plan, you’ll learn about nutritional epigenetics — the science that explores how nutrition affects our health at the level of our DNA. For instance, omega-3 fats are called essential fats because they are only obtained through dietary sources like cold-water fish and supplements. Omega-3s are good fats that have been linked to heart health.

But the health benefits of omega-3s have been called into question after research studies found that the nutrient increases the risk of cancer. In one study, researchers found that men with a higher blood concentration of omega-3 fats also had a higher risk of developing prostate cancer.  The study also found that omega-6, another essential fat, offered protection against prostate cancer.

What makes this study interesting is the fact that these essential fats, which we rely on from outside dietary sources because our bodies cannot produce them, are both crucial for good health.

  • Omega-3 fat food sources are limited and include cold-water fish (e.g., salmon, cod); the fat has anti-inflammatory effects and regulates cell growth and clotting.
  • Omega-6 fat can be found in many foods like seed, nuts, refined vegetable oils; it promotes inflammation, cell growth, and blood clotting.

Looking at the functions of these fats, you can see that when it comes to inflammation, cell growth, and blood clotting, which are all important bodily functions, omega-3 and omega-6 fats, decrease and increase these activities, respectively.

The body requires both of these fats; however, the American diet (which is high in processed foods) results in more omega-6 fats.  And a diet that is high in omega-6, without enough omega-3 fats to balance things out, predisposes the body to proinflammatory conditions, increased cell growth, and blood clotting — all which contribute to the development of heart disease, stroke, obesity, and cancer.

In order to determine whether you should avoid omega-3 fats, you must first tease out important details in the study. Here are a few things you need to know about this study:

  • “Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial” is an observational study, which used pre-existing data from an earlier study. An observational study is just that — an observation of events that happen to occur at the same time. The correlation observed doesn’t necessarily mean that one event caused the other.
  • The earlier study differed from the observational study in its objectives.  The SELECT trial was evaluating the effect of selenium and vitamin E, not omega-3 fats.
  • The data obtained was provided by a single blood draw in which blood plasma, not red blood cells were analyzed.  This further weakens the validity of the findings because plasma provides only a glimpse of omega-3 levels at that time; whereas, red blood cells offer a long-term assessment of omega-3 consumption.
  • How did the men achieve their omega-3 levels? Was it through fish consumption or supplements? If supplements were taken, what was the dose and what were the brands used? These issues weren’t accounted for by the researchers and are factors that could affect the results.
  • The study made no mention of mercury levels, which is a heavy metal toxin often associated with cancer. Measuring mercury levels is expected to correlate with omega-3 levels in most people; especially as it pertains to certain fish like tilefish and shark, which have some of the highest mercury levels. Because certain fish have high mercury levels, the most widely used omega-3 supplements have been assayed for mercury, so supplements, in general, contain little to no mercury.

There are too many variables unaccounted for in the study.  The bottom line is this observational study cannot provide any statistically significant or meaningful data to show that omega-3 fats cause prostate cancer.

Yet many studies show that omega-3s help protect against cancer. In one study, researchers found that women with breast cancer had low levels of EPA and DHA (omega-3 fats found in fish). In another study fish oil was shown to decrease precancerous polyps in the colon. Besides acting as an anticancer and cardioprotective compound, omega-3s also protect against neurodegenerative diseases, joint inflammation, and advanced aging.

While omega-3 fats are good for our health, focus on eating a well-balanced diet, exercising, and getting adequate sleep to achieve wellness and longevity.

Photo credit: V. J. Matthew/Shutterstock
  1. Brasky TM, Darke AK, Song X, et al. Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial. Journal of the National Cancer Institute.July 10, 2013.
  1. Klein EA, Thompson Jr IM, Tangen CM, et al. Vitamin E and the Risk of Prostate Cancer: The Selenium and Vitamin E Cancer Prevention Trial (SELECT).JAMA. 2011;306(14):1549-1556.