It seems that every other day there is conflicting information about the benefits of a particular diet, medication or health supplement. In recent days the health benefits of fish oil or Omega 3 fatty acids as supplementation have been called into question with the release of the Cochrane review of the role of Omega 3 fatty acids in the primary and secondary prevention of cardiovascular disease.
Please take the time to read our response to this review – it’s a little lengthy but it does address some of the failings & short comings of this report. We have provided a link to the Cochrane review at the end of this response and have also provided a link to a most excellent article written by the eminent Australian Cardiologist Dr. Ross Walker published in Medium (an online publication).
The conclusion of the review was as follows: “Increasing EPA and DHA has little or no effect on all-cause deaths and cardiovascular events (highquality evidence) and probably makes little or no difference to cardiovascular death, coronary deaths or events, stroke, or heart irregularities (moderate-quality evidence, coronary events are illnesses of the arteries which supply the heart). EPA and DHA slightly reduce serum triglycerides and raise HDL (high-quality evidence).” While the review was extensive, there were several variables which were not considered, making it difficult to draw any definite conclusions in regard to the ‘real life’ therapeutic value of fish oil supplementation. Key points from the review:
The review failed to distinguish between people who had an adequate baseline intake of Omega 3 and those who did not.
Previous studies have demonstrated that the benefits of fish oil are likely dose-dependent, with higher doses required to achieve therapeutic outcomes. No distinction was made between high and low dose interventions in this review.
Parameters considered in the study were limited to blood lipid profiles and the incidence of cardiovascular diseases (heart attack and stroke).
Improvement in other markers linked with cardiovascular health such as inflammation, blood pressure and insulin sensitivity were not taken into account.
The quality of Fish oil supplements used in the trials was not taken into account. Oxidised or tainted supplements will not have the same therapeutic effects as a pure, high quality fish oil supplement.
Statin use has been shown to limit the therapeutic effects of fish oil through various mechanisms. The use of statins by participants in the various trials was not considered.
The review did not consider the Omega 6 intake of participants in the studies. A high Omega 6 intake may reduce the therapeutic effects of Omega three by altering Omega 3:6 ratios inducing a pro inflammatory environment.
Another core limitation of the methodology in the review was the lack of distinction between primary prevention in healthy adults and primary prevention in high risk groups.
Even without distinguishing between those who had an adequate dietary intake of Omega 3 and those who didn’t, it was acknowledged that intake of additional Omega 3 increases HDL and decreases triglycerides which is obviously beneficial to cardiovascular health. While it may be correct to state that increasing intake of Omega three does not have a significant effect on the rate of cardiovascular events/mortality at a population level, the many variables excluded from this review make it difficult to draw any conclusions about the therapeutic benefits of high Quality Omega 3 supplementation when given at an appropriate dose, particularly in those whose dietary Omega 3 intake is inadequate or whose intake of Omega 6 is high.
The National Heart Foundation recommends people ideally be consuming two-three serves of oily fish weekly to reduce their risk of heart disease. They recognise that omega-3 supplements are not harmful in any way and that they can play a beneficial role in the treatment of those with high triglycerides and in the secondary prevention of heart disease. They also acknowledge that in those who struggle to meet the recommended dietary intake of fish, supplementation is beneficial. Previous studies have shown numerous beneficial effects pertinent to cardiovascular health, including the improvement of heart rate variability, insulin sensitivity, arterial stiffness, atrial fibrillation and a modest benefit in protection against heart failure. Cardiovascular disease is a complex process influenced by numerous risk factors including genetic predisposition and diet and lifestyle factors. Successful management and/or prevention requires a comprehensive holistic approach.
While supplementary omega 3 is certainly not a ‘magic bullet’ solution for cardio vascular disease, its widespread general health benefits and excellent safety record are well established.
High quality Omega 3 supplements continue to be broadly recommended for all patients at cardiovascular risk as part of a holistic treatment plan.
A link to Dr. Ross Walker’s article and the Cochrane Review are given below –
Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2018, Issue 7. Art. No.: CD003177. DOI: 10.1002/14651858.CD003177.pub3.