Fish Oil Thins Your Blood: True Or False? A Nutrition PhD Explains

When discussing fish oil myths, a few common misconceptions tend to creep up in conversation: Fish oil supplements taste fishy (not if it's high-quality!); fish oil makes you burp (it shouldn't!); and you only need 500 milligrams of EPA + DHA per day (actually, research suggests that's just your baseline, and that 1,000 milligrams [aka 1 gram] and up of EPA and DHA per day offer proportionately greater heart-health benefits1*). 

It's a question Ferira previously discussed when it comes to fish oil supplements: Can you get too many omega-3s? It's a common concern—even propagated by many health care professionals—that extremely high omega-3 intake may contribute to blood thinning and reduce blood clotting.

But according to Ferira, at normal intake levels (like from a fish oil supplement) and even very high levels none of us are consuming, this is nothing more than an old wives' tale: "The fact is, a quick look at the body of epidemiologic and clinical trial research2 over the past 30 years demonstrates, from multiple systematic reviews and meta-analyses, that there is, in fact, no increased risk for bleeding when people consume a total daily amount of EPA + DHA as low as 500 milligrams and as high as 10 grams (10,000 milligrams!)," she says regarding omega-3 supplements.

Ferira goes on to say, "Even if you wanted to be incredibly conservative and apply a random safety factor of 2 and make that daily max 5 grams (5,000 milligrams) of EPA plus DHA, those are not omega-3 levels that supplements provide. Period."

"In reality, the blood-thinning effect of fish oil actually occurs at absurdly high levels of EPA plus DHA, 10 grams and up, which by the way, no supplement even comes close to containing. Omega-3 supplements are playing in the 200- to 1,800-milligram range of EPA plus DHA 99% of the time."