Should You Stop Taking Omega 3 Fish Oil Supplements?
This past July 11, 2013 research results from Brasky et al. were published online in the Journal of the National Cancer Institute. The concluded that high blood concentrations of omega 3 fatty acids were linked to increase prostate cancer risk. Researchers state these results support their 2011 findings that omega 3 fatty acids play a role in prostate cancer.
In the few weeks since this study was published, many doctors and researchers have weighed in with their viewpoints on the study results. Let's sift through all the information and focus on what you need to know so you can decide if you should continue supplementing omega 3 fatty acids or not.
The Study This study, released by the Fred Hutchinson Cancer Research Center, analyzed participant data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT). SELECT was a large randomized, placebo-controlled trial to test whether selenium and vitamin E reduced prostate cancer risk.** SELECT was not a double-blind placebo controlled trial focused on omega 3's and prostate cancer.** Participants in SELECT had their omega 3 levels measured. It was the plasma phospholipid omega 3 levels of 834 men who developed prostate cancer and 1393 men who did not develop prostate cancer that was analyzed for this most recent research linking omega 3's to prostate cancer.
Cardiologist Dr. Stephen Sinatra points out valid concerns regarding vitamin E and its pro-oxidative effect on cholesterol. Oxidation causes the production of free radicals, which increases health concerns (ie cancer, heart disease, etc.). In SELECT, participants received 400 IU of dl-alpha tocopherol (one form of vitamin E). Many would argue that supplementing high levels of one form of vitamin E is associated with its own negative health consequences. Sharing this to show that the data analyzed from SELECT may have been 'contaminated' by the vitamin E supplementation which can impact results. Also, keep in mind that some participants were on prescription medications, were smokers, regularly drank alcohol, were overweight/obese, and/or had a first-degree relative with prostate cancer"all of which impact prostate cancer risk.
Omega 3 Levels
Here are the plasma omega 3 levels and the cancer risk found in this research:
3.62% - No cancer control group
3.66% - Total cancer group
3.67% - Low grade cancer group
3.74% - High grade cancer group
The difference in plasma omega 3 levels between the no cancer group and the high grade cancer group is not significantly different at .12%. Interestingly, the Framingham Heart Study found plasma omega 3 levels to be 5.2% in those NOT taking omega 3/fish oil supplements and 7.5% in those supplementing omega 3's"significantly higher than the levels found in SELECT participants. This may indicate that the participant data analyzed was not an accurate representation of the average population.
**Contradictory Studie **
These findings directly contradict years of research that have shown a positive link between omega 3's and health. Here are a few studies:
Brasky TM, Kristal AR, Navarro SL, Lampe JW, Peters U, Patterson RE, White E. Specialty supplements and prostate cancer risk in the VITamins and Lifestyle (VITAL) cohort. Nutrition and cancer 2011;63:573-82 (Note this is the same group of researchers reporting in 2010 no associaton between fish oil and prostate cancer.)
Szymanski KM, Wheeler DC, Mucci LA. Fish consumption and prostate cancer risk: a review and meta analysis. Am J Clin Nutr 2010;92:1223-33 (Found 63% reduction in prostate cancer mortality.)
Terry P, Lichtenstein P, Feychting M, Ahlbom A, Wolk A. Fatty fish consumption and risk of prostate cancer. Lancet 2001;357:1764-6 (Found men who did not eat fish had a two to three-fold increased frequency of prostate cancer.)
Leitzmann MF, Stampfer MJ, Mich aud DS, Augustsson K, Colditz GC, Willett WC, Giovannucci EL. Dietary intake of n-3 and n-6 fatty acids and the risk of prostate cancer. Am J Clin Nutr 2004;80:204-16 (Concluded EPA and DHA may reduce risk of total and advanced prostate cancer.)
Mina K, Fritschi L, Johnson KC. An inverse association between preserved fish and prostate cancer: results from a population-based case-control study in Canada. Nutrition and cancer 2008;60:222-6 (Increased intake of preserved fish linked to reduced prostate cancer risk.)
Fradet V, Cheng I, Casey G, Witte JS. Dietary omega-3 fatty acids, cyclooxygenase-2 genetic variation, and aggressive prostate cancer risk. Clinical cancer research : an official journal of the American Association for Cancer Research 2009;15:2559-66 (Omega 3 fatty acids found to a appear protective for aggressive prostate cancer.)
**Other Population **
Also, if we step back and look at the big picture, other cultures consume diets much higher in fish/omega 3's that Americans and suffer a much lower incidence of cancer. For example, the Japanese eat ~8 times more omega 3-fatty acids than American's and plasma omega 3 levels are twice as high. Instead of having a higher incidence of prostate cancer, the risk of prostate cancer for the Japanese is significantly lower. You could compare the diets of other populations with diets rich in fish/omega 3 fatty acids, such as Eskimos, and find similar results.
What Should You Do?
First and foremost, discuss all supplements with your doctor. Everyone's needs and medical history varies. Don't feel you need to discontinue your omega 3 fatty acids or regular consumption of fish based on the results of this research. Omega 3 fatty acids are still a valid anti-inflammatory 'tool' for promoting heart health.
Use these studies on prostate cancer and omega 3's as reinforcement that it is important to fully understand what supplements (and medications) you take and why.
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