Fish oil supplements have grown in popularity due to their well-documented health benefits, which are mainly due to their high omega-3 fatty acid content. Omega-3s help reduce levels of triglycerides, a type of fat in the blood that can raise your risk of heart disease and stroke when elevated. Additionally, because they act as antioxidants, omega-3s may also help alleviate symptoms of inflammatory conditions like rheumatoid arthritis.
Fish oil has been shown in studies to improve blood pressure and heart failure, and it even plays a role in heart disease prevention. However, because of the potent cardiovascular impacts of fish oil, individuals taking anticoagulants like warfarin should consult a doctor before taking both.
Continue reading to learn more about the possible interactions between fish oil and warfarin.
Fish Oil and Warfarin Interactions: Possible Increased Bleeding
When used independently, fish oil and warfarin have obvious benefits. However, there is the possibility that taking both simultaneously could increase the risk of bleeding, says Samer Saouma, M.D., a cardiac electrophysiologist at Northwell Staten Island University Hospital.
“Fish oil has mild blood-thinning properties and can increase the risk of bleeding in patients taking warfarin, especially high doses of fish oil (greater than three grams per day),” says Dr. Saouma.
Warfarin is an anticoagulant (blood thinner) commonly used to prevent blood clots in people at risk, such as individuals with certain heart conditions or those who have had a heart attack. The medication blocks an enzyme that uses vitamin K to create blood clotting factors, and this blocking action disrupts the body’s ability to form clots effectively.
Because warfarin interferes with clotting, it increases the risk of bleeding. Individuals taking warfarin may have occasional nosebleeds and will often bleed longer from a cut or scrape. Bleeding may even occur without a known injury. Episodes of serious or prolonged bleeding require medical attention. This side effect can be a cause for concern on its own, but it may become intensified when warfarin is paired with other drugs that impact bleeding, such as fish oil, according to an older study from 2004.
However, more recent studies call this interaction into question.
Two studies from 2016 and 2018, respectively, found no significant impact on bleeding incidence when fish oil and warfarin were taken together. While these findings suggest that taking both as directed may be safe for many people, fish oil does have subtle blood-thinning properties, and everyone has different health risk factors, so it’s important to talk to your doctor before deciding to take both at the same time.
For people who are medically approved to take both, Dr. Saouma recommends monitoring the results of a prothrombin time test (a blood test that measures how long it takes a clot to form), watching for signs of bleeding and easy bruising, as well as avoiding activities that may increase injuries and bleeding risk.
Safer Alternatives to Fish Oil
To prevent the compounded risk of increased bleeding associated with fish oil, individuals taking warfarin might consider exploring plant-based oils instead, says Dr. Saouma. Alternatives—like flaxseed oil, hemp seed oil and walnut oil—are rich in omega-3 fatty acids but safer, as they do not have blood-thinning properties, he notes.
Want to learn more about how popular medications interact with supplements? Check out another article in our interaction series: Can I Take Melatonin with Ambien?
