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Is Your Fish Oil Rancid? What you need to know.



I often talk to people about the importance of Omega 3 supplements both at my workshops and when I meet them at events.  Just like I write about food manufacturers duping us intentionally with their label (ie. Cooking spray)* it is no different with many supplements.  When it comes to buying supplements however (since there is so little government regulation) many claims can be made without justification as long as there are disclaimers on the bottle (which no one ever reads)

One of the first things I always ask is “What is it that you are looking for in your Omega 3”.

After we get past the puzzled look I say “How much DHA and EPA is in your dosage?”  Then I almost always get….   “Umm, I don’t know”.

So let’s clear this one up quickly.  The reason you take an Omega 3 supplement is for the DHA and EPA. (I remember it like this “Don’t have a heart attack and environmental protection agency” )There are different suggested amounts but in general the recommended dosage is 3000 DHA and EPA daily unless there are medical concerns for the average person. 1.   Here is the kicker – Just because it says 1000 mg of fish oil on the front does not have any relation to how much DHA (Docosahexaenoic acid) and EPA (Eicosapentaenoic acid) there are in the dosage.  All it means is that there is 1000 mg of fish oil (usually inactive)

Okay, here we go.

Nature Made Fish Oil supplement.  They sell this at Costco and most pharmacies and box stores.  Many people use this one.


By the way, the 600 DHA/EPA is a real improvement.  However,  look at the ingredients.  Contains: Fish (anchovy and sardines (that’s good) and.. wait for it – yes Soy! And water and tocopherol.

My favorite is Mega Red.  Ready…..

People take Mega Red for their fish oil supplement.  Don’t get me wrong, krill oil is a great antioxidant, but it is not a source of Omega 3.  It has an  EPA of 45 and a DHA of 27!  That means your dose each day to get the recommended amount of DHA/EPA would be a whopping 41.67 pills! Yikes! For an omega 3 supplement…  the krill is gone baby. 

So there are two new major points I want to talk to you about.  You had better sit down for the first one.  It really upset me.


 Yep, you heard me, rancidity.  Something I never really thought about before.  I have said it so many times.  You don’t know what you don’t know and what you don’t know can really harm you. 

Sorry about this folks but if I don’t tell you, I would be remiss.

“The omega-3 project is being carried out jointly by NIFES, the Department of Nutrition at the University of Oslo, Uppsala University and the Centre for Clinical Studies Bergen AS.

.., In addition, the project will examine the potential negative health effects of rancid fish oil. While it would seem obvious that fresh fish oil is healthier than old, rancid oil, the actual effects have never been adequately documented. 

“Rancid fish oil smells bad and tastes so awful that no-one would want to swallow it. But if the fish oil is in capsules, it is impossible to smell if it is rancid or not. That is why it is important for us to examine whether rancid fish oil is less beneficial to health, or, at worst, harmful to anyone who takes it,” asserts Frøyland. 

One of the possible negative impacts of ingesting rancid fish oil to which Frøyland is referring is what is known as oxidative stress in the cell membrane, i.e. where oxidants break down the cell membrane.

“The tests show that fish oil from capsules caused oxidation of the cell membrane, even when antioxidants had been added and when the capsules still had over a year left before their expiration date” 

Rancid fish oils, like other free radicals, are harmful to your health and may cause damage to your body at a cellular level. Rancid fish oil may increase your risk of heart disease, atherosclerosis and blood clots 2

Not only are you increasing the oxidants in your body, but you have to use the one’s you already have to combat the very pill you are taking to increase your antioxidants!

So, you are getting this, right.  Those gel caps that you are taking may be rancid and you would never know it.

So the last part of this equation here is an important factor that we don’t often think about.  Absorption.  How much of the stuff we are taking do we actually absorb?

According to several studies (and I have linked them at the bottom) Encapsulated Fish Oil was tested against “Emulsified” Fish Oil (liquid) for absorption.  The short version is that it was determined that the liquid fish oil had significant higher levels of absorption when tested over a 48 hour period 4.


Over a 48 hour period there was enhanced absorption of total n–3 and EPA (0.67 ± 0.16, 0.45 ± 0.06, p<.01; 0.34 % ± 0.05, 0.23 % ± 0.04, p= .05; EFO and CFO respectively) was observed for the EFO treatment.

Health benefits of omega-3 fatty acids (n–3) are well established. However, consumption of adequate dietary sources of these fatty acids is inadequate

The typical dietary intake of n-3 fatty acids in the Unites States is far below recommended consumption levels (16). Current daily intake is 0.1 % of total energy while the Acceptable Macronutrient Distribution Range recommended intake level is 0.6-1.2% of energy (17).

The need for LCn3 cannot be met by only increasing α–linolenic acid (ALA, 18:3n-3) consumption in the current Western diet.

I made that bold.  I want you to understand what that says.  ALA (alpha-linolenic acid) (flax seed) is not a good source for DHA, EPA


Our findings indicate that a single dose of the EFO resulted in enhanced absorption of total n-3, EPA.

According to a major Fish Oil manufacturer,- In fact, “Liquid fish oils will have up to a 97% absorption rate, while gel caps typically have a 60-70% absorption rate.  This is a little known fact outside of the scientific community, but well known within the pharmaceutical industry.” 9

Fish oil: “This is where fish oil may have an advantage over fish. Because it is molecularly distilled and purified, fish oil can have high concentrations of DHA and EPA…., a level that would be difficult to obtain from eating fish. You’d have to eat approximately 8.5 ounces of wild salmon every day to obtain that much DHA”.3

Lastly, and you really need to know about the mercury levels and pcb’s in our fish.


Here is a fun fact.  Web MD released a study that showed that farmed raised fish had lower mercury levels than wild. 6 The study however, was funded by the Canadian Fishing industry which supplies an abundance of the salmon eaten in the US.

Of course, the study did not address the increased pcb’s (polychlorinated biphenyls) in farmed raised fish or as we fondly call it “franken fish”  I wish I had named it that.

A study found the greatest PCB levels in salmon from farms in northern Europe and the lowest levels in fish farmed in Chile. They concluded that eating farmed Atlantic salmon, “may pose health risks that detract from the beneficial effects of fish consumption.”

*As an aside here, much of the encapsulated fish oil comes from salmon (wild or otherwise)

Farmed fish can also absorb PCBs and dioxins, as the near-shore waters they occupy are the first stop for run-off from land-based sources of pollution. And the fact that their primary feed source comes from conventionally grown terrestrial crops means that their diets can include trace amounts of pesticides and herbicides as well. Also, most farmed fish are exposed to dose after dose of antibiotics to keep diseases and pests at bay in their crowded underwater pens, much in the way “factory farmed” land animals are drugged to help them cope with cramped, unsanitary conditions. In fact, studies have shown that farm-raised fish have more toxins overall than their wild-caught cousins, though exceptions of course do exist.8

According to the EPA (Environmental Protection Agency) “It is thought that Methyl Mercury can harm the heart, kidney, immune system.  More studies are needed”

What happens is that because of industry and natural occurring events mercury is released into the water.  Unfortunately, fish and ultimately those who eat the fish absorb the mercury and PCB’s as well. .  Here is the important point about this.  Some fish have higher levels of mercury than others and often these fish are used to produce your cheaper fish oil.  Read your labels.  It should come from small fish like anchovies and sardines.  The smaller the fish, the less the toxicity.

So the take away from this is according to the EWG (Environmental Working Group)  An important watch dog group.


Shark, Swordfish, King mackerel, Tilefish, Tuna steaks
Canned tuna, Sea bass, Gulf Coast Oysters, Marlin, Halibut
Pike, Walleye, White croaker, Largemouth bass


Mahi mahi
Blue mussel
Eastern oyster
Great Lakes salmon
Gulf Coast blue crab
Channel catfish (wild)
Lake whitefish


Blue crab (mid-Atlantic)
Fish Sticks
Flounder (summer)
Haddock Trout (farmed)
Salmon (wild Pacific)
Shrimp *

* Shrimp fishing and farming practices have raised serious environmental concerns.
** Farmed catfish have low mercury levels but may contain PCBs in amounts of concern for pregnant women. 7

Dr. Loren Cordain suggests that on a Paleo Diet, we only need two supplements.  Omega 3 and Vitamin D3.

Hopefully you now understand why I recommend a liquid fish oil.  Not a capsule or tablet.  You can’t get the required dosage of DHA/EPA in one capsule but you can in one teaspoon.  You don’t know if the fish oil you are getting is rancid in a capsule.  You need to look at the source of your fish oil and lastly read your labels!


  1. (University of Maryland.
  2. – ixzz2VXhjtNXj
  8. WB0rcCFUtk7Aod5h0A6A
  9.   John Abare, Stronger Faster Healthier
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7 Comments on "Is Your Fish Oil Rancid? What you need to know."

  1. Glenn June 11, 2013 at 12:40 pm · Reply

    Hi Eileen,

    Currently I am taking a prescription fish oil called Lovaza. It contains approximately 465 mg EPA and 375 mg DHA per 1GM capsule. My dosage is 4 1MG capsules per day which should get me to the recommended 3000 EPA/DHA per day. Are you familiar with this product? Also, what liquid fish oil product do you recommend as I would like to compare prices, etc.

    Lovaza is sourced from a variety of fish oils and does not contain any mercury or other toxins, but it does contain soy I believe.


    • Eileen June 11, 2013 at 1:00 pm · Reply


      I am aware of Lovaza. I know it is a Dr. prescribed Omega. While I never interfere with a Dr.’s suggested protocol I can tell you that of my clients that show the SFH that I recommend to their doctors, they have switched to mine.

      I would challenge the absorbency of the tablet vs the liquid and I can tell you that the dosage is only 1 time a day with the liquid and it is probably less expensive.

      Hope this helps.



  2. Eileen June 12, 2013 at 12:42 am · Reply

    Hi Eileen, great article. I have mercury toxicity. The fish oil my physician Dr. Mark Hyman has me on is Metagenics EPA-DHA Liquid High Concentrate. They’ve just updated their entire selection, and now are calling it Omegagenics. I don’t necessarily push one brand, but this page talks about their testing. It is available online via many carriers. This brand is often found in alternative practitioner offices. Because I’ve been undergoing chellation for mercury, this was the safest one for me to be on. It’s only 1-2 tsp/day. And it is not fishy at all, (unless you drop it and wipe it up with a dishtowel! …learned the hard way on that one!). Also, a great site to check besides the Environmental Working Group’s supplement review is the Environmental Defense Fund’s page on fish.

    Metagenics explanation:

    Environmental Defense Fund Worst and Best Fish:

    Thanks for something important to keep in mind when shopping for supplements!

    • Eileen June 12, 2013 at 2:20 am · Reply

      Thanks for the info. So sorry to hear you are dealing with mercury toxicity. I am glad you have something to help and a Dr. who is on the ball. I am a very big fan of the EWG. Thanks for posting.

  3. Allessio July 13, 2013 at 5:32 pm · Reply

    If I have to dump my Twinlab TwinEPA fish oil tabs for liquid….well, its just not going to happen. The universe of people who will voluntarily take a liquid fish oil is way smaller than the universe that will take the gel caps. And the group that will take any fish oil product is already much smaller than the population. This is really bad news!

    Are u sure this is true? Don’t good manufacturers stabilize the fish oil somehow in the encapsulating process. Are there not any GMP’s for the transportation and storage of fish oil products? Have you checked with the manufacturers for their response?

    • Eileen July 13, 2013 at 6:57 pm · Reply


      Thanks for taking the time to write. I have never told anyone to “dump” what they are using. I do however offer the most up to date researched information I can find. What you choose to do with that information as always is your choice. I believe I linked the studies pertaining to the rancid fish oil although there is much information available on the web. In addition even without the rancidity, absorption levels are still much lower. I am glad however that you are taking fish oil. Your product offers 715 mg of EPA/DHA and also has glycerin, gelatin, d-alpha tocopherol.



  4. Julien February 18, 2014 at 1:07 pm · Reply

    Great read, thanks a lot

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