Over the past two decades there has been a significant debate in the medical literature regarding the potential benefits, detriments and, possibly ineffectiveness, of omega 3 fatty acids. Around a decade ago, Hooper et al, released a large meta-analysis suggesting that consuming fish and fish oil may, not only be of no benefit, but even potentially may cause harm.

One of the major reasons for the potential harm was the contamination of the fish supply, especially in the northern hemisphere, caused by the heavy shipping lines and the subsequent ingestion by the fish supply of methyl mercury and dioxins. This has even led to the suggestion that pregnant women should not consume fish because of the potential damage to the unborn child from these contaminants.

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In 2013, a meta-analysis of just under 70,000 people looking at 20 trials showed no benefit or harm from omega 3 fatty acids supplementation in regards to reduction in cardiovascular disease. But, a number of other studies, especially those that looked at high risk populations have concluded that there is a significant benefit.

Basic science has shown clearly that omega 3 fatty acids:

1) Improve blood flow to the organs by a direct effect on the blood vessel wall;

2) Exert a direct effect on blood triglyceride levels. It is a little-known fact that omega 3 fatty acids aids in converting small LDL to large LDL, the healthy lipid profile. Because there is not an overall reduction in LDL levels, many ignorant researchers feel that the benefits from omega 3s on the lipid or blood fat profile are not particularly significant.

3) They also have a weak effect on thinning the blood by having a direct effect on platelet function - the sticky cells very important in blood clotting.

4) There is a significant anti-inflammatory effect. Omega 3 fatty acids specifically generate prostacyclin and reduce the generation of thromboxane A2, both very important in improving blood flow and reducing inflammation.

5) There is also a direct effect on the heart by improving the rest & rejuvenation system. A recent study has shown improvement in cardiac function after a heart attack when high dose omega 3 fatty acids were used.

6) Some very good work shows omega 3 fatty acids have an important action as anti-arrhythmics , therefore calming an irritable heart.

With all this clear scientific information, we must ask ourselves why the studies do not show any clear benefits in a number of cases? A recent meta-analysis from the Mayo Clinic sheds important light on this and I believe is a strong answer as to why the studies are not particularly supportive of the use of Omega 3 Fatty Acids.

This meta-analysis published in the first edition of Mayo Clinic proceedings for 2017 looked at 18 randomised controlled clinical trials which is where fish oil ingestion was compared with placebo in high risk groups and 16 prospective cohort studies which basically looks over time at a group of similar individuals comparing their intake of various substances, in this case omega 3 fatty acids. This is where I believe the answer is quite clear. In the randomised controlled trials there were 93,000 subjects, a significant number included, but, the problem here was only one trial was extended for seven years and the vast majority of the trials were somewhere between 1–5 years. Even though most scientists would prefer to see a randomised controlled clinical trial over a prospective cohort study, the prospective cohort study had 732,000 subjects where the follow up period was much longer with one even extending 40 years and the shortest trial six. The vast majority were well over 10 years of follow-up.

The findings from this meta-analysis were interesting in that there was a non-statistically significant reduction in cardiovascular risk of 6% in the people who had a significant daily intake of omega 3 fatty acids, either through fish or supplementation but in the prospective cohort study there was an highly significant 18% reduction for any cardiovascular event in the people who had higher intakes of omega 3 fatty acids.

Thus, it is my opinion that we must look at the ingestion of Omega 3s over a long period of time and ignore the early results. I’ve made the point on a number of occasions that supplements and food are not like heavy pharmaceutical drugs. Pharmaceutical drugs have strong effects but also the potential for strong harm. Whereas most good-quality foods and good quality supplements have less strong effects but in the long-term when the studies are analysed correctly are showing significant benefits.

It is my strong opinion that we should be increasing our intake of omega 3 fatty acids either through fish or supplementation.

A recent simple new test known as the Omega 3 Index is the best way to determine your current level of omega 3 and subsequent necessary intake. The Omega 3 Index is a pin prick blood test that takes a drop of blood and analyses the amount of omega 3 in your red cell membranes, which is very closely linked to the omega 3 throughout all of your cell membranes.

Unfortunately, in most western countries the average Omega 3 Index is very low, often around the 4% range. The studies clearly show an Omega 3 Index above 8% is in the healthy range and this typically requires at least 1 gm daily of omega 3 fatty acids to achieve this level. I was delighted when I had my level measured recently & it was just below 12%. A recent study from the New England Journal of Medicine showed that the Omega 3 Index level was a better predictor of sudden cardiac death than cholesterol. In fact, people with the lowest Omega 3 Index compared with those with the highest have a 90% higher risk for sudden cardiac death.

In conclusion, I believe the evidence is clear it is important to have a regular and high level of omega 3 intake and it is also important to know your Omega 3 Index with this simple test.

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Dr Walker is an expert in the field of preventative cardiology and has published seven books. He gives lectures nationally and internationally.

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