Professor Christian Hamilton-Craig
Fish oils are Omega-3 poly-unsaturated fatty acids.
The Heart Foundation recommends all Australians should aim to include two to three serves of fish (including oily fish) per week as part of a heart-healthy diet.
Fish oils are a source of Omega-3 fatty acids. It is the Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) which are the main omega 3 fatty acids that have been studied and shown to be of benefit for heart health. Omega-3 supplementation reduces cardiovascular mortality and improved cardiovascular outcomes.
Confusion exists about the benefits, or lack of benefits, from Omega 3 fish oils.
This is partly due to clinical trials having different doses of EPA and/or DHA, and the variation in the amount of EPA/DHA found in various fish oil supplements.
In general, a single capsule of 1000mg fish oil (such as you might buy in bulk from a chemist) contains only about 30 per cent of the active ingredient EPA/DHA. This means that to get 1000mg of EPA/DHA, you need to consume three to four tablets a day!
It doesn’t matter where you get the Omega-3 oils from, either from dietary fish intake or supplements, as long as you have >1000mg of EPA/DHA intake to be effective.
Double or triple-strength fish oils contain a higher dose of the EPA/DHA which is the effective ingredient. Krill Oil is a more expensive way of increasing Omega-3 intake and has fallen from popularity in recent times.
It is useful to note that not all fish oil is derived from fish.
Much of the EPA/DHA in fish oil comes from the algae eaten by the fish.
Vegan omega-3 supplements derived from algae are available. Alpha-linolenic acid (ALA) derived from plants also benefits cardiovascular health and reduces rhythm disturbances (eg atrial fibrillation AF).
What about bleeding? Some surgeons, and even some guidelines, recommend stopping fish oil before elective surgery. However, recent data suggest that increased fish oils were actually associated with reduced bleeding (Journal of the American Heart Association, June 2021).
Importantly, Omega-3 fish oil supplementation has the greatest benefit in people who have low levels of Omega-3 in their system.
Most doctors don’t know it, but you can measure the Omega-3 Index which is a simple blood test that measures the amount of Omega-3 in your red bloods cells.
People whose Omega-3 Index is low (less than four per cent) are at increased risk of heart attack and sudden death, whereas those whose Omega-3 is high (above eight per cent) are at a 90 per cent reduced risk of cardiovascular events including sudden death..
In summary: Omega-3 fish oil supplementation is safe, but requires a decent dose of EPA/DHA to be effective. Double and triple-strength supplements may be more convenient to take, and are most effective if your Omega-3 Index is low.
