Why Fish Oil?


Updated June 2012

Disclaimer: I am not a doctor. Whatever you put into your body, do so at your own risk. All I intend to describe is what I do and why I do it. I consume 5400 milligrams (5.4 g) of Omega-3 fatty acids via fish oil daily at a body weight of 185 pounds.  I recommend a proportionate dose for most adults. I even give fish oil to my dog.  Dr. Barry Sears said of fish oil, “It’s as close to a miracle drug as I’ll ever see in my lifetime.” I agree.  Below is a very concise explanation of why.  If you just want to take my word for it (something I don’t recommend) then skip to the section titled “How Much Fish Oil Should I Take?” If you wish to read a more exhaustive explanation I recommend the Wikipedia articles on omega-3 fatty acids and fish oil, or reading the references I have linked.

Fish oil, which includes Cod-liver oil, is a significant source of the Omega-3 fatty acids DHA and EPA.  These fatty acids have numerous, documented health benefits: improved cholesterol balance, reduced inflammation, increased blood flow, reduced rates of heart disease and atherosclerosis, better immune system function,improved brain function, improvement in psychiatric disorders, and prevention of cancers (particularly breast, colon, and prostate).  Improved blood flow and reduced inflammation are of particular interest to athletes.  This enables an athlete to train harder and recover faster.

Even for the non-athlete, the benefits of fish oil are profound.  Including the benefits listed above, studies have shown that fish oil can cause weight loss and improved body composition even when supplementing a very poor diet.  I advise everyone to eat a diet rich in lean meat, fruits and vegetables, nuts and seeds, with as little starch and refined sugar as possible. However, if you simply refuse to change your diet then I highly recommend you take fish oil.  It’s super easy and will go a long way towards counteracting those McDonald’s extra value meals.

The only significant negative effect of fish oil is that when taken in large doses and combined with drugs like aspirin, it can cause increased bleeding.  This doesn’t mean you will bleed out from a paper cut, but it could be significant if you incurred a life-threatening injury.  This would probably only happen in rare circumstances where you take an extremely large dose and combine that with an anti-coagulant like Aspirin and suffer life-threatening bleeding. I think the benefits far outweigh the risks, but that’s a decision you must make for yourself.

How Much Fish Oil Should I Take?

First, ignore the recommended dosage on the fish oil bottle. Most Americans consume enough Omega-6 fatty acids that the recommended dosage on the bottle would be laughably low in keeping your Omega-3 to Omega-6 ratio in check, which is one of our primary goals of supplementing fish oil. Next, the amount of fish oil you take isn’t nearly as important as the amount of Omega-3 (n-3) fatty acids in that fish oil. We are just taking the fish oil for the n-3’s, so it makes sense to pay attention to the n-3 content of your fish oil. This varies wildly by brand and quality. You’re looking for the EPA and DHA content of the fish oil. This will be listed on the back label.

To make things simple, total the milligrams of EPA and DHA to get a single amount of n-3 content. So what’s a good number? I’ve seen fish oil from Wal-Mart that has less than 200 mg total per capsule. That’s pretty poor. Most quality fish oil will have about 600 mg per capsule. That’s pretty good. Anything over 600 mg per capsule is pretty potent stuff, sometimes called “pharmaceutical grade.” If your brand doesn’t list the EPA and DHA content at all (it’s not required by law), then ditch it. That means it’s so pitifully poor that they’re ashamed to list it. Lower quality fish oil also causes “fish burps” much more frequently than high quality fish oil.

Below you can see an example of a fish oil nutritional label. Notice the serving size is 2 capsules. Each serving has a total of 720 mg of EPA and DHA. Therefore, each capsule contains 360 mg of EPA and DHA. That’s not terrible, but it’s not very good either. You’ll have to consume a lot of capsules to get the necessary n-3 content. Always pay attention to serving size. Many manufacturers (like the one below) will try to trick you into thinking you are buying extremely high quality fish oil by listing a single serving as 2 capsules. They know everyone assumes the nutritional information on the back is given for a single capsule.

Fish Oil Nutritional Data

For comparison, I would have to consume 15 capsules per day of this fish oil to get the same n-3 content that’s in 6 capsules of the more potent fish oil that I take. If you’re serious about getting the correct amount of Omega-3 fatty acids (remember, we’re only taking fish oil for the n-3 content, not the fish oil itself) then bargain brands of fish oil are no bargain at all.

I use Member’s Mark triple strength fish oil from Sam’s Club. After tax it is a few cents more than $20 for a bottle of 150 capsules. Each capsule contains 1400 mg (1.4 g) of fish oil and 900 mg combined EPA and DHA Omega-3 fatty acids. I currently take 6 capsules per day, each with 900 mg of combined n-3 content. I consume the capsules in two equal doses with breakfast and dinner. That works out to 5400  milligrams (5.4 g) of n-3 per day. That is not the same as milligrams of fish oil. Each capsule is 1400 milligrams of fish oil, so I am taking 8400 mg (8.4 g) of fish oil to get 5400 mg (5.4 g) of Omega-3 fatty acids. The n-3 content is what’s important, not the fish oil itself.

In his book, The Paleo Solution, Robb Wolf makes different dosage recommendations based on level of athleticism. He recommends 1g of EPA/DHA per 10 lbs of body weight for sick, overweight, and highly inflamed individuals. For lean, muscular athletes with blood chemistry closer to ancestral norms, he recommends .25-.5 g of EPA/DHA per 10 lbs of body weight. All things considered, I recommend athletes use the upper end of .5 g per 10 lbs of body weight. Use the below tables as a rough guide.

Fish Oil Dosage for Sick and Obese
Fish Oil Dosage for Sick, Overweight, or Inflamed
Fish Oil Dosage for Lean Athletes with Proper Diet
Fish Oil Dosage for Lean Athletes with Proper Diet

If you’re not ready to jump into consuming that much fish oil, that’s OK. I didn’t start out taking that much daily. If you’re apprehensive then just start with a couple capsules. Once you’ve seen its positive effects then you may want to consider taking more.

More Evidence

Below is a 15-minute video by Barry Sears on the benefits of fish oil, including his results treating Manuel Uribe.  Manuel was the heaviest man on earth at over 1200 pounds.  Eighteen months after adhering to a Zone diet and supplementing with extremely high doses of fish oil he had lost 400 pounds and had the blood chemistry and resting heart rate of a well-trained athlete.  He currently continues his multi-year path to a normal body weight using the Zone and fish oil.  Dr. Sears begins discussing fish oil about 3 minutes into the video.

Video links:

33 thoughts on “Why Fish Oil?

  1. Yeah, but is it as good as Centrum Silver or those little packets of horse feed that they sell at GNC? Ha ha!

    I take about 3g a day right now. Luckily, I’ve avoided the legendary fish burps that I’ve heard so much about. I’ve heard that storing them in the freezer gets rid of the burps, though.

    Any thoughts on good brands (both quality-wise and cost-wise)? I get the double or triple strength purity capsules from Sam’s right now (Member’s Mark brand), depending on what’s available. Concerning EPA/DHA content, they’re only about 15 cents/gram as opposed to 10 cents/gram (after tax) for the single strength capsules. This allows me to take fewer pills and consume much less useless filler. That’s worth an extra 15-20 cents a day to me.

    Also, is it recommended to spread the intake over the day, or is it acceptable to take all of it at once? I generally take half in the morning and half at night.

    Good video. Great post!

  2. Adam, my research concluded that any readily available fish oil in a popular super market is going to be of acceptable quality. I haven’t compared the potency of EPA/DHA doses by brand. We get what is available at our supermarket and I don’t worry about it. I am also unconcerned with burps. Sometimes I burp and can taste fish, but to me this is analogous to driving past roadkill: mildly unpleasant, but not so bothersome that it’s going to change the way I operate.

    I spread my intake over the course of the day. I do not know if loading up is better.

  3. Hiatal hernias can make fish burps a bit annoying. Storing the capsules in the freezer didn’t make much of a difference for me, you’re experience may be different. I’ve found that taking the capsule before eating helps and never wash them down with coffee. Big mistake. I take mine all at once, no way I’ll remember to take them multiple times a day.

  4. There is a difference between fish oil and cod liver oil. All cod liver oil is fish oil, not all fish oil is cod liver oil.

    1. I’m glad Men’s Health didn’t jump to any conclusions on that, but I wish they had included more information about the study. Below is a link to Mark Sisson’s (marksdailyapple.com, Primal Blueprint) take on it. Check out that (“low-carb”) pie chart toward the middle of the post–at least two thirds of the fats consumed by the participants were unaccounted for in the study.


      Mark isn’t perfect, but he does his research and usually writes very balanced, informative articles. I agree that more studies need to be performed (preferably in vivo) in order to be more conclusive. What worries me is that other media sources will likely report the findings and not any of the details, or worse, try to push their own agenda with it without even providing a link to the study itself (see http://www.vegsource.com/news/2011/04/study-fish-oil-increases-aggressive-prostate-cancer.html).

      Below is a link to the study, which unfortunately requires either a subscription to the American Journal of Epidemiology or $40 to have access to the article for a day (though students may be able to get around this).


      1. Jason, thanks for bringing that to our attention. Thought-provoking.

        Good resources, Mandy. I had wondered if other aspects of diet were controlled in the study, and it appears they weren’t. So participants could have been living off 5 meals a day of omega-6 heavy fried food. They could also have been eating completely paleo. The point is that human physiology can’t be measured and quantified in a vaccuum. All the systems are interrelated. Let’s compare rates of prostate cancer among those who consume little grains and sugar, get plenty of fat and protein, and supplement with fish oil compared to those who eat the average American diet, and then see what happens.

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