Common Fish Oil Questions Answered: A Baker's Dozen

25 Jun 2010 03:36

By Eric Troy

Here at Ground Up strength you can find the answers to most common questions regarding fish oil in the various articles we have but we have some fairly heavy reading so you need to dig a bit to find the particular answer you're looking for. So I thought I'd write a blog post that provided simple answers to the most common questions about fish oil supplements. I will keep these answers short and to the point in a radical shift from my usual style although a few will be a bit longer for the purpose of clarity.

Although I started with thirteen questions, a Baker's dozen, I have since expanded this article to include an additional two questions.


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More Fish Oil And Omega 3 Fatty Acids Articles

1. How much fish oil should I take a day?

1 to 6 grams. Currently, there is thought to be no benefit to consuming more for any reason, whether general health or therapeutic, such as for cardiovascular health. Only part of the total fatty-acid content of fish oil is Omega-3 EPA and DHA. Since levels vary it is difficult to give an exact ratio but this dose range of fish oil should correspond to about 200 mgs to 1200 mgs combined EPA and DHA per day.

2. Does taking fish oil supplements work as well as consuming actual fish for omega-3 fatty acid status?

Yes. But fish is good food and there are other benefits to consuming it. There is also controversy and risks. See Fish, Mercury, Selenium and Cardiovascular Risk: Does the Danger of Mercury Outweigh the Benefits of Fish Intake? for further info.

3. Should I buy fish oil capsules or a liquid fish oil supplement?

It is a matter of personal preference. Capsules are much more convenient for most people and you are more likely to take them than to consume liquid fish oil. There is no concrete reason to believe liquid fish oil supplements are better but capsules are more processed which opens the possibility of more oxidation than a liquid supplement. However, based on the results of third party tests on common fish oil supplement brands there is no reason not to buy whichever form you prefer.

back label nutrion panel carlson liquid fish oil

Carlson Liquid Fish Oil Nutrition Panel

4. Should I keep my fish oil supplement in the refrigerator?

Most fish oil brands advise you to keep the product in a cool dry place, tightly closed, after opening. A very few advise to keep the product in the fridge after opening. I personally keep mine in the fridge because all polyunsaturated fatty acid oils should be kept in the fridge after opening. And fish oil is especially fragile. There is some concern over the possibility of condensation appearing on the cold capsules when you open the container thus introducing moisture. Most bottles come with desiccant packs and I have never personally witnessed any condensation on fish oil capsules because they are cold, but the question remains.

5. Should I buy pharmaceutical grade fish oil?

There is no such thing a pharmaceutical grade fish oil. There may be some benefit to buying a fish oil product that hold the USP Verified Dietary Supplement seal, which is strictly a verification of manufacturing process and potency (the product meets label claims). But this seal is not strictly necessary to assure a good product. Rumor has it that the USP is developing a monograph for "fish oil products containing Omega-3 fatty acids" but as far as I know it is not yet official.1

6. Should I by a more expensive fish oil supplement or a more concentrated one?

No. More expensive does not mean better for fish oil supplements.

7. I like to buy my supplements at a warehouse club like Costco, Sam's, or BJ's. Are the fish oil supplements they sell okay?

Yes. These products tend to do as well as any other common retail brands of fish oil in third party tests. I buy the Berkley & Jenson (BJ's) brand of fish oil myself. The Kirkland brand, by costco, is also a good and economical choice.

8. I found a great deal on fish oil. I can get 5000 capsules for 5 bucks? Should I go for it?

I wouldn't. I did say expensive didn't mean better but a deal like that is "too good to be "good". And 5000 or even 1000 fish oil capsules at one purchase is probably way too many. They will go rancid before you ever use them unless you have a Brady Bunch family and they are all popping the fish oil capsules. About 300 at a time is about the most you should buy.

9. Do I need a fish oil supplement with more DHA? Or should I buy some other type of "designer fish oil"?


10. I opened up my bottle of fish oil capsules and it smelled very fishy. Does this mean it has gone bad?

Yes. Fish oil should not smell fishy. It should not smell rancid in any way. Throw it away.

11. My new bottle of fish oil capsules has a strange and pungent odor. I can't describe it but it's not really fishy or rotten smelling. It reminds me of plastic, in a way. Is it bad?

Are your capsules enteric2 coated? These coatings are used to delay dissolution of the capsule in the stomach until the capsules reach the small intestine, to alleviate the fishy aftertaste, burping, or indigestion that some people experience. Some of the common components of these coatings may have an acrid and very disagreeable odor.

Many sources will tell you that these coatings are poisonous. Although I would question some of them, they are mostly inert polymers. However, if the coating on the capsules make them stink, these coatings could also mask or confuse the odor of rancidity. Methacrylic acid, in particular, could be a culprit. I would avoid enteric coatings, many of which fail to do the job anyway3. Most of digestion problems mentioned above can be solved by simply taking smaller doses several times a day rather than two large doses. Buy smaller fish oil capsules to begin with.

However, do not worry about the enteric coatings if the fish oil capsules you have are coated. If the ingredient list of a fish oil capsule proclaimed "5,8,11,14,17-eicosapentaenoic acid" and "4,7,10,13,16,19-docosahexaenoic acid" as components these same reactionary sources would no doubt shout "chemical soup!" Poison! Yet these are the scientific names of the sacred EPA and DHA Omega-3 Fatty Acids.4

12. I've read that the capsules that fish oil comes in are toxic! Is this true?

These highly reactionary and largely unscientific reports refer to the enteric coatings, mentioned above, used on some capsules and presented to the consumer as a CHOICE. Since many of the chemicals (organic or otherwise) have long scientific sounding names they are assumed to be toxic by those who think that any additive with a long name is toxic. The capsules themselves are made of gycerin and gelatin and are not harmful at all.

13. As long as I keep my fish oil closed it can't really go bad can it?

Yes it can and it will. I am aware that some people believe that as long as you don't open your fish oil it won't really expire. In fact, some people think that expiration dates on fish oil products are nothing more than a hoax by the manufacturer to get you to buy more product than you need. Well, if that is what you have been led to believe, you've been told wrong.

Fish oil starts going bad or 'rancid' through the process of oxidation pretty much as soon as it is processed. This is why manufactures put in antioxidants such as vitamin E. And it is also why fish oil capsules or liquids tend to come in brown bottles or opaque ones to protect them from photo-oxidation. Just like good beer! No, clear plastic bottles are not good for fish oil so if a product comes in a clear plastic bottle, don't buy it. But regardless of what kind of bottle it comes in it will eventually spoil whether you open it or not.

Of course you don't keep your fish oil closed, you open it every time you take some but even if you never opened it it would eventually go rancid. The first time you open it and expose it to air the process will speed up. But auto-oxidation means the process will continue without any further input from the environment. For more information on this and a whole lot more see Fish Oil Quality

14. What if I've Been Using Rancid Fish Oil Without Knowing. Is This Bad for My Health?

Yes, it could be. When fish oils go rancid, many different compounds, such as peroxides, are produced, which may be bad for your health. Although many health effects have been postulated, there is not enough data to know exactly how this may effect your health. One significant effect may be on your gastrointestinal health.

Be aware that not all fish oils are created equal, and some products have been found to be rancid before they are even bought. There may even be a greater risk of a fish oil product being rancid than there is for it being contaminated with heavy metals, microorganisms, or other things. The potential rancidity of a product is related to how the oil is extracted, processed (refined and concentrated), bottled or encapsulated, and stored and transported. 3

15. Is it possible to take too much fish oil?

YES! It's possible to over-consume anything. See Fish Oil: Just the Facts

16. I have type 2 diabetes and I hear conflicting advice on wheter I should take a fish oil supplement or not. Some people say it is beneficial and some people say that diabetics should not take it until more is learned. What should I do?

First, don't consult Dr. Google OR Dr. Eric about such questions!

Consult your doctor or a registered dietician and ask him or her to research it if they do not know. Right now there is far from definitive science on this subject. Certainly there seems to be a benefit in terms of lipid disruption (termed dyslipedemia) which in type 2 diabetes is most commonly elevated triglyceride levels and decreased HDL cholesterol levels. And remember that even if you're diabetic your lipid levels can be impacted by other things as well. But the impact of omega-3 fatty acids on glucose control in T2DM and other associated conditions of diebetes is not clear at all.

I cannot and will not give medical advice on this blog. I can say that, anecdotally, many diabetics claim they have a hard time controlling their glucose levels while consuming a fish oil supplement and that the problem goes away as soon as they stop taking it. So consult you doctor first. If you do choose to take it, start with the smallest amount possible, monitor your levels, and build accordingly.

16. Are there any good alternatives to fish oil for getting the Omega-3 Fatty Acids EPA and DHA?

Alpha-linolenic acid (ALA) was touted as being just as good for increasing the omega-3 index as fish oil. However the conversion of ALA to EPA and DHA in humans is inefficient and inconsistent in humans. While the biological health role of ALA itself still remains to be thoroughly investigated, flax oil and other high ALA oils or foods should not be considered a good alternative to fish oil.[1]

Recently another fatty acid called stearidonic acid has been investigated. Stearidonic acid is a long chain (n-3) Polyunsaturated Fatty Acid which rapidly converts to EPA and is about 4 times more efficient in doing so that ALA. A new soybean oil will soon be available to supply more of this fatty acid and it is likely that supplements will be available in the future.[2] DHA is readily available in supplement form derived from algal oil rather than fish oils.

17. Is it true that most fish oil products are of very poor quality and extremely underdosed?

This is related to question number nine, above. The answer is no. This is not true. Let's start with "underdosed." The dosing refers to the proportion of Omega 3 Fatty Acids within the fish oil, specifically EPA and DHA, as discussed above. To say that a fish oil product is underdosed, is to say that it contains less of these fatty acids than it's label claims. Many pushers of expensive types of Omega 3 oil products would like you to believe that there is some standard "dosing" that the oil should contain, but this is silly. Most common fish oil products, including those that can be purchased at drug stores or department stores, tend to meet their claimed amounts of EPA and DHA.

There is no standard concentration of EPA and DHA in fish oil. In fact the concentration can vary by ten times, and the processing also, of course, affects this concentration. So, it is possible for a fish oil to contain very low levels of these fatty acids, say as low as ten percent or less. But most fish oil products will contain moderate to extremely high levels, with higher levels being more common, meaning at least around 45% up to as high as 90%. All you have to do, if your product contains a low amount of EFA's is to adjust the number of pills you take throughout the day. When buying, look for a higher concentration…which may also mean smaller pill size, if this is a concern for you.

Remember, you are paying for each miligram of EPA and DHA you get. Some of the new expensive products, such as Krill oil or Algal oil, may cost up to 60 cents per 100 grams of EFA's, as opposed to only as high as 15 cents in regular fish oil products. Yet, the quality is the same! A typical good quality fish oil gel contains 1000 to 1200 mgs of fish oil (1 to 1.5 grams), yielding 400 to 500 miligrams EFA's per gel.

The idea that fish oil products are "underdosed" comes from the mistaken belief that there is a common therapeutic window and if the amount of EFA's in one "dose" does not fall within this window, the fish oil will not "work." First, there is no common therapeutic window that we know of. Different clinical reasons for using fish oil have had different daily amounts attached to them and a general health reason has a general amount attached to it. If your fish oil has a very low percentage of EFA's, the problem is you'll have to take more of the pills and this means more oil and more problems with fishy after taste and potential digestive disturbances. But this is usually not the case and most inexpensive common fish oil brands can be easily adjusted to your needs without having to spend a great deal more on fancy designer brands.


1. Anderson, Breanne, and David Ma. "Are All Omega-3 Fatty Acids Created Equal?" Ground Up Strength. LIpids in Health and Disease. Web. 18 Sept. 2010.
2. Whelan, Jay. "Dietary Stearidonic Acid Is a Long Chain (n-3) Polyunsaturated Fatty Acid with Potential Health Benefits — Whelan 139 (1): 5." Journal of Nutrition. Web. 19 Sept. 2010. <>.
3. "Product Review of Fish Oil Supplements (Including Krill Oil and Algal Oil Supplements) by" - Independent Tests and Reviews of Vitamin, Mineral, and Herbal Supplements. Web. 13 Dec. 2011. <>.

This page created 25 Jun 2010 03:36
Last updated 26 Sep 2013 11:43

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