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Something fishy about Omega-3 supplements?

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by Ross Walker

Omega-3 supplementation, in all its various preparations, is the best selling supplementation in Australia. But, many recent large trials of Omega-3 have suggested no cardiovascular benefit, and one study suggested a potential increased risk for prostate cancer in people that had high levels of Omega-3 in their blood stream.

A recent Four Corners program suggested fish oil capsules are easily oxidised and can become rancid and offer trigger inflammation, exactly the opposite to the purpose for which they are intended.

Secondly, the program suggested that the University of Auckland research in 2015 showed that in a sample of 32 different fish oil products, only three of the 32 contained the concentrations stated on the bottle and half of these supplements exceeded the recommended levels of oxidation products.

Finally, the program concluded that fish oil capsules do not protect against heart attack for primary prevention i.e. those people who have not suffered heart disease and secondary prevention for those people who already have existing heart disease.

So, should we ignore this information, or accept this information as fact and relegate all Omega-3 supplementation to the scrap heap? Let’s look at the evidence.

Firstly, are Omega-3s easily oxidised, and in this state, do they trigger inflammation? If the University of Auckland data is correct, it suggests the vast majority of Omega-3 products may not only be ineffective, but may also cause harm. Since this research was initially conducted, the Australian Therapeutic Goods Administration (TGA) has retested a number of fish oil and other Omega-3 products in Australia and found that all of the products tested returned acceptable results for both the oxidation status and the content of Omega-3 fatty acids. I therefore feel we can put this first point aside as it does not appear to be relevant.

Secondly, assuming that Australian Omega-3 supplements do have the correct dose with no significant oxidation products, is there any evidence that Omega-3 works in the first place?

Firstly, to start at the basic science level, there is no doubt that Omega-3 supplementation shows benefits in all these areas.

  1. Varying doses reduce triglyceride levels with emerging evidence that there are some benefits converting small, dense LDL, which is the pro-atherogenic component to large, buoyant LDL with also an effect on raising beneficial HDL cholesterol. There is also evidence that Omega 3 supplementation can help with fatty liver.
  2. The anti-thrombotic effects of Omega-3s are mild but certainly present and don’t prevent combining Omega-3 with stronger pharmaceutical agents for blood thinning such as Aspirin and Warfarin.
  3. Endothelial function. It appears from the numerous studies performed that there is a small but significant improvement in endothelial function with the use of Omega-3 supplements.
  4. Autonomic function. There are variable responses with heart rate variability, but there are some studies that suggest augmentation of vagal activity and therefore improved cardiac autonomic function.
  5. Cardiac function. There are a variety of parameters that are benefitted by the use of Omega-3.
  6. Anti-inflammatory actions – there are a number of evidence-based trials especially in conditions such as rheumatoid arthritis where Omega-3s have been shown to be beneficial.
  7. Antiarrhythmic benefits. The basic science shows clearly that Omeg-3s do show benefits in stabilising electrical activity in the heart.
  8. With this myriad of various physiologic and patho-physiologic benefits, the following question then should be asked. Why don’t most of the clinical trials of Omega-3 supplementation in humans show any significant benefit?

Firstly, the largest trial of Omega-3 supplementation was the GISSI Trial from Italy involving 11,000 patients following a heart attack and given 1gm of Omega-3 fatty acids for twelve months. This trial showed a 45% reduction in sudden cardiac death. This was statistically significant and hardly should be ignored. Many recent trials of fish consumption and fish oil capsules from the Northern Hemisphere have shown no real benefit, but it is highly likely that the products used here were contaminated by mercury and dioxins from the heavy shipping lines in the Northern Hemisphere. The standards of production of many supplements in the Northern Hemisphere may be questionable, as demonstrated by the recent Four Corners program, which was purely based on North American examples.

The earlier studies of fish consumption have shown somewhere between a 30-50% reduction in cardiac events from the long term consumption of fish. The Inuit, the Fins and the Japanese, who have a high level of fish intake, all show very low rates of cardiovascular disease over a long period of time.

A recent meta-analysis of 20 studies of 68,680 patients showed no real benefit from Omega-3 supplementation.

In my view, the problem with this meta-analysis was that the groups were extremely heterogeneous with some participants in the study for primary prevention, others for secondary prevention and others with severe heart failure and even those with implantable defibrillators. The other major problem with most of these studies was the average length of the trials was only two years.

Many conservative researchers in science who are researching complementary medicines do not understand that the supplemental therapies are much gentler with much less side effects but also much less strong effects.

To see a benefit from supplements in terms of heart events, it is my view that you need to have trials that are conducted well beyond ten years and there are not many nutraceutical companies that have the funding or the patency over one particular product to perform such widespread, intensive and extremely expensive trials.

Therefore in my opinion the body of evidence is in favour of Omega-3 supplementation. But taken alone it should not be seen as a panacea and should be used in combination with healthy lifestyle principles and other supplements such as multivitamins where there is strong suggested evidence for benefits.

For many years I have continued to recommend to all my patients that when they reach around age 35-40 they should commence on a multivitamin and Omega-3 supplementation and continue to do so all throughout their lives.

Published: Thursday, June 09, 2016


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