Fish Oil: Why More Isn’t Better

Filed under: General Health, Nutrition

I have mentioned this point many times before, but I don’t think I have ever written a formal piece on the topic. The fact of the matter is that no matter how many incredible health benefits fish oil provides, there comes a point where its supplementation can actually be more detrimental than beneficial.

This often comes as news to a lot of health-conscious individuals, but it is true all the same.

The two major fatty acids in fish oil, EPA and DHA, have an unfortunate track record of suppressing our immune system. There is also the matter of oxidation. EPA and DHA are polyunsaturated fats, and polyunsaturated fats are the least stable and most likely to be oxidized.

When we consume an excessive amount of polyunsaturated fats this can become a problem. The body incorporates the fatty acids you consume into cell membranes and phospholipid bi-layers, so when polyunsaturates are consumed in high amounts, more of them are incorporated into the cells, leading to the increased risk of oxidation. Of note saturates are the least likely to oxidize and are the most stable.

Now, back to the suppressed immunity from excessive fish oil consumption. This downside has a substantial and consistent amount of data behind it (though the beneficial aspects of fish oil have a mountainous and consistent amount of data as well, and growing).

I want to focus on a few studies that have found this effect. The first was a 12 week study on several different fatty acids. They compared the consumption of ALA (flax, walnuts), GLA (borage oil, evening primrose oil), AA (animal foods), DHA, or EPA and DHA. The total amount of EPA and DHA was only 1 gram. The only treatment where immune function was compromised was the EPA and DHA supplementation. This combination led to a decrease in natural killer cell activity by 48%. Interestingly the just DHA group (720mg) did not have this effect, so it appears that EPA has this effect.

The second was also a 12 week study where men young and old consumed only EPA on immune function. As expected the EPA was incorporated into the phospholipids of cells. At doses of 1.35, 2.7 and 4.05g/day the EPA supplementation caused a dose-dependent decrease in neutrophil respiratory burst. I had no idea what that meant, but it indicates the suppression of a cellular defense against immunity threats.

I will again state that though there are some downsides to fish oil supplementation, the amount of benefits from its supplementation are through the roof. The point today isn’t to scare you away from supplementing, the point is to make your supplementation reasonable. I suggest aiming for 1-2 grams of combined EPA and DHA per day. I personally find 1 tsp of Carlson’s The Very Finest Fish Oil to be the perfect amount, supplying 1.3g of combined EPA and DHA from one the highest quality and well-priced fish oils available.

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Posted on December 9th, 2010 by Brian St. Pierre


  1. Rhys I Says:

    Which flavours the best with the Carlson’s fish oil Brian? Also what doses do you usually recomend? (i’m mid 20′s and 240lb’s incase that influences dose?!?)

    Thanks as always!

  2. Rhys I Says:

    Oh and also i have been readin about Udo’s choice oil lately, heard some people say you don’t have the issues of oxidisation as badly due to it not being fish oil? Is this a product you’ve used or written about before? Any thoughts?

    Again thanks for your help!

  3. Kujo Says:

    Very interesting. I’ve read that too much fish oil can be bad before, but it’s always been much higher dosages.

    I know 3-6 grams of combined EPA/DHA has been recommended by many. Berardi recommends dosages based on body fat percentages.

    I take a liquid fish oil brand basically identical to Carlson’s ( but much cheaper.

    I take two half a tbsp servings a day, which equals about 2.7 grams of EPA/DHA.

  4. Jon Says:

    What’s the basis behind the 1 to 2 grams/day recommendation? Why would someone need more or less per day?

  5. Brian St. Pierre Says:


    I prefer the lemon myself, but the orange is pretty good too. I usually recommend 1-2g total EPA/DHA per day from fish oil. Since you are 240lbs, you would probably be up near 2g, but it would really depend on the rest of your diet. If you eat a lot of fatty fish, for example, your supplement need might be less.

    I think Udo’s is actually a pretty good product and I have used it before. My wife and I both found that it improved our skin significantly. Now it still contains a lot of polyunsaturated fats so it is just something to keep in mind.


    There can certainly be situations where more EPA/DHA is indicated, like specific medical issues or if someone has consumed virtually no EPA/DHA, is significantly overweight and has consumed a highly-inflammatory diet for an extended period of time. This is a scenario where JB recommends taking a lot of fish oil, but I am not sure he recommends taking such large doses forever. If you are an otherwise healthy individual with a proper bodyweight and balanced diet, there is just no need for excessive supplementation.

    Your fish oil product seems excellent, however I will point out that if you are taking 1 tbsp per day, that actually comes out to 3.9g of EPA/DHA per day.


    The basis is that is the general consensus of the research where you get the most bang for your buck with the least amount of side effects. Someone might need more for the reasons I listed in above responses, and they might need less if they are a small individual (say a 110lb woman compared to a 250lb man) or if they consume cold-water fatty fish on a regular basis.

  6. Kujo Says:

    Haha, my math was way off. I multiplied by 2 instead of 3.

    I think I`ll reduce my dosage to half that, and see how I feel.

    On days when I eat herring, salmon, or sardines, I`ll take less via supplement form (maybe just a 1 tsp). I have sort of been doing that recently.

    Brian, since you take just 1 tsp a day, do you take in the morning or evening? Just curious.

  7. Max Says:

    Other than Carlson’s Fish oil is there any other brands that you would recommend??? I own a personal training business in Melbourne, Australia and we have been searching for a cheap place to import Carlson’s Fish Oil for our clients because here it can cost close to $70.00 for the 500ml bottle. Which is way too expensive

  8. Brian St. Pierre Says:


    I take it in the morning.


    The brand that Kujo takes seems fine and that might be more accessible to you.

  9. Great links for the weekend! Says:

    [...] couple of articles about fish oil.  The first is by Brian St Pierre about why potentially you can find that too much is a bad thing.  The second is a brief piece from [...]

  10. Vacation Food Choices: Besides the Beer « Matt Siniscalchi Strength & Conditioning Says:

    [...] Want to know more on fish oils?  Read this blog-post from Brian St. Pierre.  He knows his stuff when it comes to supplementation and [...]

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