Fish Oil vs. Krill Oil

09 Jun

A typical softgel

Health-wise, fish oil may no longer be the biggest fish in the sea (pun intended).

It’s well-known that fish oil, which is extracted from oily cold-water fish such as salmon, halibut and mackerel, has a load of health benefits, including lowering cholesterol, preventing blood clots and potentially offsetting health problems such as arthritis pain, menstrual pain and ADHD.

More and more scientists are getting excited about krill oil…supplement companies are advertising krill oil as superior to fish oil…and, as you may have noticed, more stores are selling krill oil. So the question is—is krill oil, which is extracted from very small shrimplike creatures, better for our health than fish oil?

I called an expert in oils—Bethany Thayer, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics in Chicago. I think you’ll be intrigued by what she had to say…


Fish oil: When comparing any given amount of krill oil to fish oil, fish oil contains more (usually 33% to 50% more) omega-3 fatty acids known as EPA and DHA—these are antioxidants that protect cells from harmful changes caused by free radicals. Prices vary widely, but fish oil also tends to be about 30% to 60% cheaper than krill oil because fish oil can be derived from more sources. Since the dosing for fish oil and krill oil is typically the same, fish oil will leave less of a dent in your wallet.

Krill oil: Though there is only about one-half to two-thirds as much EPA and DHA in a given amount of krill oil, the EPA and DHA that is there is 20% to 30% more “bioavailable”—meaning that more of it is easily absorbed by our bodies because of its molecular makeup. That means that krill oil is digested better by humans, and, therefore, it is much less likely to cause the “fishy burps” and gross aftertaste known to affect some fish oil users. And unlike fish oil, krill oil contains the antioxidant astaxanthin, which crosses the blood-brain barrier, so it protects the brain and central nervous system from free radical damage even better than fish oil does.

Let’s see what the research shows…


One big challenge in comparing the two oils is that only a handful of studies on krill oil exist overall, but for fish oil, they number in the thousands! But here are the few studies that pit the two oils against each other…

  • According to a 2011 study published in Journal of Animal Physiology and Animal Nutrition, krill oil produced significantly greater declines in cholesterol and liver triglyceride levels than fish oil in rats. Winner: Krill oil.
  • According to a 2004 study from McGill University in Canada published in Alternative Medicine Review, krill oil was significantly more effective than fish oil at lower and equal doses at reducing blood levels of sugar, triglycerides and LDL “bad” cholesterol in people. Winner: Krill oil.
  • According to a 2003 study of women of reproductive age (age 33, on average) published in that same journal, krill oil supplements were more effective than fish oil at reducing breast tenderness, joint pain and emotional symptoms associated with premenstrual syndrome (PMS). It’s worth noting, however, that two of the study authors worked for a krill oil manufacturer. Winner: Krill oil.
  • According to a 2010 study of 113 patients in the journal Lipids, blood levels of EPA and DHA increased just as significantly in those given either fish oil or krill oil over seven weeks, compared with those given a placebo. Winner: Too close to call.


These study results sure do make me think that krill oil is at least equal to, if not superior to, fish oil for general wellness. But Thayer said that more research needs to be done on krill oil to be able to declare it the true “winner,” since, as I mentioned earlier, only a handful of studies on krill oil exist overall.

When I asked whether it would be a good idea to take both fish oil and krill oil every day, she said that taking both in full doses could provide too much omega-3, which might lead to bleeding because these oils work as natural blood thinners. Her suggestion is to take either just one of them or to alternate.

Some warnings from Thayer before taking either krill oil or fish oil: Avoid taking either if you’re allergic to shellfish or seafood, because either might cause a reaction. If you’re pregnant or breast-feeding, talk to your doctor before taking either supplement, since their safety is unknown. You may also want to talk to your doctor first before taking either supplement if you’re on a blood thinner, because krill and fish oil are natural blood thinners and may cause an excess. Also ask your doctor whether it’s a good idea to avoid taking either in the week before surgery, because of the blood-thinning effect.

Source: Bethany Thayer, MS, RD, spokesperson, Academy of Nutrition and Dietetics, Chicago, and director, wellness programs and strategies, Henry Ford Health System, Detroit.

Leave a comment

Posted by on June 9, 2012 in Health and Science


Tags: , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: