Do Omega 3 Fish Oil Supplements Cause Blood Thinning?

Most people now know that eating plenty of oily fish and other omega 3 rich foods as well as taking omega 3 supplements is beneficial to their overall health. However, some people have heard that taking too much omega 3 might thin their blood too much, posing a risk for excess bleeding. Many people therefore assume they need to avoid taking fish oil supplements if they are taking anti-platelet or anticoagulation drugs or are due for surgery. However, this may not necessarily be the correct course of action.

Omega 3 can help with a plethora of inflammatory and cardiovascular conditions and it is known that adults can safely take up to 5,000mg or 5g a day. Omega 3 plays an important role in the growth and development of the brain, the regulation of blood pressure, kidney function, blood clotting as well as inflammatory and immunological outcomes. It is now also thought to be beneficial for those people who are suffering from COVID-19-associated cardiovascular complications such as blood clots.

Omega 3 rich foods include salmon, mackerel, sardines, organic milk, walnuts, flax and chia. Omega 3 supplements can be derived from oily fish or vegan marine algae which is the food that these fish eat in the ocean.

It’s sometimes difficult to picture how much 5,000mg/5g of omega 3 is. So, in practical terms, one 150g serving of Sockeye Wild Salmon provides around 4,000mg of omega 3 fatty acids, and a piece of farmed salmon the same size is more like 1,800mg. Most good quality fish oil supplements contain a daily dose of around 1,000-1,500mg of omega 3 fatty acids which is not that much compared with eating wild salmon.

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Can you take omega 3 alongside medications?

The answer is generally yes. Drugs like aspirin and clopidogrel are often given when a person has a high risk of cardiovascular health outcomes, and some think they should stop taking fish oils if they are taking these medications. However, a study done back in 2010 in Poland found that the addition of omega 3 supplements to a combination of aspirin and clopidogrel significantly helped the platelet response to clopidogrel and helped it to work better.

In 2007 Dr William Harris carried out a meta-analysis of 19 clinical studies involving more than 4,000 patients who had been through major surgery. These people took daily fish oil supplements at doses ranging from 1,600mg to 1,200mg of omega 3 per day and they also took aspirin or heparin which are two common blood-thinning drugs. This review concluded that the risk of problematic bleeding was virtually non-existent, even when combined with aspirin or heparin which are well known to increase the risk of bleeding.

Equally a study of over 2,000 people found that omega 3 oil supplementation did not significantly alter the effect of a blood thinner called Warfarin or increase bleeding incidence. The only time you really need to avoid taking is Omega 3 supplements with warfarin is if the person has sustained a traumatic brain injury.

Do I need to stop taking fish oils if I am having an operation?

Bleeding complications are always a major concern with any surgical procedure and again some people stop taking omega 3 supplements in the run up to and after an operation just in case the omega 3 leads to significant blood thinning and post operative blood loss.

However, the scientific research tells a very different story, and according to European Food Safety Authority EFSA it is thought that taking up to 5,000mg of omega 3 daily is safe and does not increase the risk of adverse bleeding episodes. It is in fact thought that upping omega 3 intake may even be beneficial to post-operative healing and in some clinical settings, they appeared to actually reduce the risk of bleeding and may also reduce post-operative atrial fibrillation.

Can I take omega 3 around the birth of a baby?

The benefits to mother and baby of taking omega 3 before, during and after pregnancy include reducing the risk of premature birth, reducing risk of post-natal depression and positively affecting the IQ and cognitive outcomes of the baby. And it is thought that it is safe to continue to take the omega 3 in the days before and after the birth, whether the mother has a vaginal or caesarean delivery. Again, it does not seem to affect vaginal bleeding, blood loss at delivery or reduce the mother’s haemoglobin levels due to blood loss.

Omega 3 whether consumed regularly in the diet or taken as a food supplement can be such a beneficial, simple and natural intervention and it’s great to know it might even be helpful if you are due for an operation or need to take a blood thinning medicine.

This is not medical advice, and you should always consult your doctor if you are in any doubt, as they will be able to advise you about what is suitable for you personally.

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  1. I had a stroke a couple of years ago and have been taking plavix and baby aspirin. My doctor recently told me to stop the plavix and just take baby aspirin but I forgot to mention omega 3 fish oil . I take 3 capsules a day 1200 mg – is that ok?