Health Articles
Fish Oil vs. Krill Oil: Which Should You Choose?
Posted on March 1, 2018 2:50 PM by Dr. Zimmer
I get asked all of the time why I do not recommend krill oil over fish oil. To many the evidence is so seemingly overwhelming in favor of krill oil that it really does not make sense why anyone would still be taking anything else. I can say that I have always been slow to jump on bandwagons. And, it seems, for good reason. All of the noise generated by the bandwagon can easily distract you from the fact that you are going in the wrong direction.
The truth is that the evidence does not support the use of krill oil. In fact, the evidence shows that krill oil has only one benefit over fish oil and that is the lack of a fishy burp that some people experience from fish oils. The major negative is that krill oil is about 5-6 times more expensive than a good quality fish oil.  So, it should have a significant and measurable benefit over fish oil to justify the increased costs. I would also like to point out that never in the history of man-kind has krill been a food source for humans. Thus, although krill oil comes from nature, it is not natural to the human diet.
Let’s examine the krill oil claims and see if they pass the sniff test.

Krill Oil’s Claimed Benefits
The most important fact you need to be aware of when people refer to “studies” supposedly supporting the claims of krill oil is that all of these studies have been done by the krill manufacturers. In and of itself, this does not mean that a study done by someone who has a financial interest in the outcome will always be bad. But, it most certainly means that you should take a closer look at the study’s claims before giving it a big accepting kiss on the lips.

Claim #1:  Krill Oil Is Absorbed Much Better Than Fish Oil
In one study of 76 obese adults, some were given 212 mg of EPA from fish oil and some were given 216 mg EPA from krill oil. (EPA is one of the beneficial omega 3 fatty acids found in these oils)  The fish oil group increased their plasma EPA levels by 81% while the krill oil increased by 89%. Looking at this in a direct manner the krill oil seems to be slightly better (89% vs. 81%) at similar doses. However, that is not the way studies are evaluated to determine whether there is a real difference. You have to determine a benefit through statistical significance. In other words, you have to look at other possible causes for the differences and take them out of the equation. When this is done there is NO statistical difference between these results. Thus, scientifically and clinically this study showed zero difference between krill and fish oil. It most certainly does not support the claims that krill oil is absorbed significantly better than fish oil.
The same principle affects the other study which is touted as having shown a benefit of krill oil absorption over fish oil. In this study subjects were given 543 mg of omega 3 from krill oil and 864 mg from fish oil. Even though the average increase in omega 3 was higher in the fish oil group, the higher amount was not statistically significant. Thus, krill oil advocates claim this shows that krill oil is more effective at a lower dose.  (Notice how they ignore the principle of statistical significance when it is not in their favor, but embrace it when the opposite occurs.) By itself, this study is not impressive and cannot be utilized to tout the superior absorption of krill over fish oil.
Many of the advocates for krill (Mercola, Oz, etc.) claim that the reason why it is better is because krill supplies the oil in a different form (phospholipid form) than natural fish oil (triglyceride form). Dr. Oz even showed an animation with the krill oil moving into the body at about a 5 times faster rate than the fish oil. He presented this animation as if there were solid and convincing scientific studies supporting this claim. NONE exist!
The only small study (12 subjects) looking at a direct comparison between krill oil and fish oil showed NO statistical difference between the oils studied. But, there was “a trend towards higher plasma phospholipids” with the krill oil. This is what the advocates latch onto to make their exaggerated (bordering on dishonest) claims. The reason why using this finding to make such bold claims about krill oil is dishonest is because it ignores the fact that the fish oil would more likely be absorbed in a different manner. For example, imagine if you bring your groceries into your house in both plastic and paper. You would not count the items in the plastic bags as the only ones “absorbed” into your house. Thus, this study tells us little about krill absorption benefits over fish oil. It most certainly does not support the exaggerated claims of 5 times the absorption!

Claim #2:  Krill Oil Contains Antioxidants Which Will Benefit Your Health
It is true that krill oil contains the carotenoid Astaxanthin. And, it is true that there are a few limited studies showing that Astaxanthins may be of benefit for your health. But, these studies used dosages of 4 mg up to 20 mg per day. Krill oil contains only about 0.5 mg of Astaxanthin per capsule. So, making any health claims because of the Astaxanthin content is called wishful thinking, at best. But, this does not stop exaggerators like Dr. Mercola from making ridiculous statements like; “Astaxanthin and this unique marine-source flavanoid in Pure Krill Oil creates a special bond with EPA and DHA, allowing for direct metabolism of the antioxidants.” He literally just made that up to promote the krill oil he is selling. NO studies to date have shown any health benefits from the antioxidants found in krill oil and because of the minute quantities found in the oil, none would be expected. These claims are wishful thinking mixed with exaggeration and topped with a sprinkle of dishonesty.

Claim #3:  Krill Oil Does Not Give You That Fishy Burp
As far as I can tell this is true.
But, there is something fishy about krill oil. The lengths to which the krill industry will go to try and publish studies that will promote their profits is disturbing. Two recent studies are the perfect example of why you have to find out who is paying for a study before you get that tingle down your leg because of the results.
In one study they claimed, “Krill oil supplementation lowers serum triglycerides without increasing low-density lipoprotein cholesterol (LDL) in adults with borderline high or high triglyceride levels.”  The problem is that at the highest level of supplementation, 800 mg of krill oil, the triglycerides actually INCREASED! So, how were they able to make the claim in the title of their study? They did it with creative mathematics. In other words, if the numbers do not show what you want, make them show what you want.
In the second study, they claimed to have studied equal amounts of krill oil against fish oil. Except they adulterated the fish oil by mixing it with corn oil and did not disclose this in their study. When they were called to the carpet on this they replied, “We agree that we could have included the information about dilution of fish oil in the original manuscript itself.” But, they did not for some reason. My best guess is that they did not want to highlight the fact that you would have to take about 4 capsules of krill oil for every 1 fish oil. So, they diluted the fish oil to keep the krill oil dosage seemingly low. Comparing krill oil to an adulterated fish oil renders the study’s conclusions meaningless. But, that has not stopped advocates from using these studies to promote krill oil.

The Danger Of Taking Krill Oil
The real danger of taking krill oil is that you are being told it will provide the same benefits for your health as will fish oil, but at a much lower dose. Think about that for a moment. If they acknowledged that this was untrue, which seems to be the case, a bottle of krill oil with equivalent amounts of omega 3 as fish oil would cost 5 times as much. No one would buy it. So, they have to try and prove this claim or the whole industry would collapse. They are not going to let this happen and with the help of over-zealous pitchmen like Drs. Mercola and Oz they are accomplishing a successful deception.
The other potential concern, which I have not heard anyone else raise, is that the exoskeleton of krill must be removed before eating because it contains fluorine. Fluorine and its anion Fluoride are toxic at high concentrations. I could not find any information as to whether the krill industry is testing their product for fluorine content. I am not sounding an alarm because I do not know whether they are testing for this element or its anion (fluoride). But, it certainly is of concern with an industry that has shown itself to be less than honest in the representation of their product. Are you willing to trust them on this or would you like to know for sure? I am not so trusting.
Finally, if you go to PubMed and type in Krill Oil you find that there are only 164 articles in the peer reviewed literature. If you type in Fish Oil you find 29,466 articles. With the questions surrounding krill oil, why not pick the one that has 180 times as many studies?
So, if you have been riding the krill oil bandwagon you might want to consider jumping off and letting it go banging down the road without you.  Or, you can go on spending 5 times as much as a good quality fish oil and keep your fingers crossed that the deceptive health claims promoted by those making a profit are real.

Buying A High Quality Fish Oil Is Important
You may have noticed at the beginning of this article I disclosed that I am a proponent of taking HIGH QUALITY fish oils. People ask me all of the time whether it makes a difference as to where they get their fish oil. I am here to tell you, in my not so humble but educated opinion, that taking fish oils you bought at Costco, Sam’s, WalMart, Target, Walgreens, CVS, the Vitamin Shoppe or on the internet may actually be more harmful than helpful for your health.
The reason has to do with two factors: pesticide residues and rancidity. Only the best brands, which are usually only sold through doctor’s offices, test their oil for both of these potentially health harming molecules. Some test for pesticides, but not for rancidity. If you take a rancid oil, you are taking an oxidant, which is just the opposite of an antioxidant (most people know antioxidants are good for you).  Taking a pro-oxidant rancid fish oil is not a good idea if you want to improve your health. But, this is exactly what you may be doing each day!
Some fish oils become rancid at the time of encapsulation. Many others become rancid as they sit in non-temperature controlled warehouses by the tens of thousands of bottles waiting to be shipped to their final destination. Others contain extremely long expiration dates and eventually become rancid because they have sat on a shelf for too long. Thus, I do believe it is possible to potentially harm your health in the long-run by taking poor quality fish oils.
I urge you to stop taking store-bought fish oils. Consider taking Dr. Zimmer’s Pure Omega 3 Fish Oil. Contact me and I will send you a coupon for your first bottle. That way you know you are getting only the best for the money you spend. Why not take the best for your health? Other good brands include Metagenics, Thorne Research, Designs for Health, OrthoMolecular Products (who make my oils for me) or Nordic Naturals.
God bless and I hope this article was educational.