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Why I micro-dose fish oil supplements

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Fish oil supplements are a controversial topic.

As we touch on in our fish oil buying guide, most fish oil supplements contain rancid and damaged fats and the content of EPA and DHA (the two most important types of omega-3 fatty acids) is often overstated. In some cases, low quality fish oil supplements contain more saturated fat than they do omega-3 fats.

In extreme cases, fish oil companies have been caught red handed perpetrating major scams. For example, Chris Kresser has written about his experience with a “cod liver oil” company that was actually found to be using Alaskan pollock.


So, right off the bat, one reason to be a little more conservative with dosing fish oil is most of it contains bad stuff. The best companies, like Rosita, are very expensive, so most of us won’t want to spend the money it would take to mega-dose the highest quality fish oils. 

Long term studies on fish oil cast doubt 

Then there are the conflicting studies, with the long term benefits of fish oil uncertain at best. For example, multiple meta-analyses, which are summaries of many different studies, have found that taking fish oil does not prevent heart disease.12 But then you have the recent Vascepa trial, which looked at the impact of taking 2g of medical grade EPA twice a day on the incidence of stroke and death from heart disease. The death rate and heart attack rate was lower in the group taking the EPA medication. 

The Vascepa trial was published in the New England Journal of Medicine, however, despite the promise of this one study, fish oil supplements have been associated with bad outcomes in other studies.34

When fish oil studies show harm it’s usually the result of large daily “mega-doses” at or above the 3 gram mark, and yet the proponents of omega-3 supplements like to argue that lack of efficacy in some clinical trials is often the result of doses being too low. This was the argument of our industry insider in a recent podcast we did on the supplement echo-chamber and his views seem to be backed up by the Vascepa study. 

Which leads us to the communities of “bio-hackers” who take as much as 40 grams of fish oil a day, which in my view is not a good idea for most people. With the questionable quality of most fish oil on the market, the mega-dosing group is not getting a product that is anywhere close in quality to the pharmaceutical grade Vascepa. 

So, yes, the fish oil world is a murky place. I wouldn’t blame you for opting out entirely.

Omega-6 to Omega-3 ratio remains important 

But then you are faced with a difficult dilemma: how do you get adequate amounts of omega-3 fatty acids, especially if you follow a more plant based diet?

Supplementing with fish oil remains controversial, but the benefits of adequate omega-3 in the diet is not. For example, this study, appearing in the Australian and New Zealand Journal of Psychiatry, which found that EPA supplementation was just as effective at treating depressive disorder as was a commonly  prescribed prescription drug. Or this study which found that balancing the fatty acid intakes of elderly women (by giving them 2.5 grams a day of EPA) improved symptoms of depression. 

So, what I hear you saying at this point is, wait a minute, all the beneficial studies you’re citing administered heavy doses of omega-3, and you’re micro-dosing? 

Yes, luckily I am not sick with heart disease and I am not depressed. At this point, that level of intervention isn’t necessary for me. Instead, I want to be vigilant about keeping my omega-6 to omega-3 intake in balance. Too much omega-6 hinders the ability of the body to get and use EPA, so as my intake of omega-6 relative to omega-3 goes up, my levels of healthy fats overall go down. 

Fish oil is a tool I use to keep things in balance and more aggressively target my omega-6 to omega-3 ratio.

For example, even inside of a single day of eating, the benefits of a small dose (around a tsp) of Rosita Cod Liver Oil are obvious when you start to track your macro and micronutrient ratios. Using an app like Cronometer, you can see the change in omega-3 to omega-6 ratio when direct EPA and DHA is added into the diet. In the visual below, a dose of cod liver oil, as well as some algal oil, bumped my omega-3 intake up to a ratio of about 2.5:1 omega-6 to omega-3. 

Side note: Cronometer adds in the trans fat whenever you use oil, and in this case I cooked eggs in a combo of ghee and avocado oil. That gave me the fractional uptick in trans fat. 

Why does balancing omega-3 to omega-6 fats matter? 

When we eat more omega-6 fatty acids (as we tend to do in the modern day Western diet) than beneficial omega-3 fats, the result is inflammation. Omega-6 fats, like linoleic acid, convert in the body to arachidonic acid (ARA), a potent stimulator of the immune system. ARA metabolism produces substances called eicosanoids, which are pro-inflammatory and stimulate the immune sytem.56

The meat and eggs we eat are already higher in linoleic acid as a result of the industrial farming system feeding corn, soy and other low quality GMO grain to these animals. Next, factor in all the vegetable oils found in everything from gluten free bread to your favorite salad dressing, to your morning omelette at the local diner, and you’re in an omega-3 pit. Not only that, you’re stimulating the immune system on a loop with the increase in ARA that the omega-6 rich diet causes. 

Could this imbalance be a contributing factor to the rise in autoimmunity? Possibly, which leads me to the coolest paper I found while doing this research. Titled Polyunsaturated fatty acids, inflammation and immunity, the paper says this about ARA, omega-3 and inflammation: 

The n-6 PUFA arachidonic acid (AA) is the precursor of prostaglandins, leukotrienes, and related compounds, which have important roles in inflammation and in the regulation of immunity. Fish oil contains the n-3 PUFA eicosapentaenoic acid (EPA). Feeding fish oil results in partial replacement of AA in cell membranes by EPA. This leads to decreased production of AA-derived mediators. 

Interesting that the intake of different PUFA can change the composition of cell membranes such that we shift from a state of inflammation to a more neutral state where recovery is possible. 

Testing EPA / DHA to determine fish oil dose 

Ok, so let’s say you’re a little low on omega-3 and want to shift to a better 6:3 balance.

You can compensate by eating wild salmon and other fatty fish, and probably should, but even the best of these fish carry a toxic burden. It’s likely not wise to eat fish every day of the week, no matter how pristine. And here’s the thing: eating fatty fish is no guarantee that your omega-3 fatty acid levels will be where you want them at your next blood draw.

And those are the words that drive my decision to take small doses of fish oil, “blood draw.” 

The fish oil regimen any of us take should be tailored to our lab results. If we’re low on EPA and DHA, or if we want to better balance the ratio of arachidonic acid to EPA, take the amount of supplemental EPA and DHA you need to get the ratios in check. Don’t take more. There is a proven benefit to balancing out omega-3 to omega-6 consumption. There is not a proven benefit in taking mega-doses of over the counter fish oil. 

Back to my lab work. 

Genetic variants that determine EPA / DHA levels 

I regularly eat wild salmon from Bristol Bay, as well as pasture eggs on occassion, but still find that my EPA and DHA levels are sometimes lower than I would like on blood tests, and this is the case despite the fact that my FADS1 SNPs are thought to be more effective at converting omega-3 plant fats into the long chain omega-3 fats the brain can use. This means I do have the ability to get some of my EPA and DHA from plant sources, although genetically not everyone is so lucky.

Let’s delve into that issue for a second in case there are any Vegans reading this post. 

Certain variants in FADS1 are associated with a decreased ability to convert alpha linoleic acid (or “ALA” is the omega-3 fat found in plants like walnuts and chia seeds) into EPA and DHA. The brain needs EPA, and especially DHA, to function properly, and with omega 3 deficiency linked to mental illness, most plant based eaters will want to take an algal oil supplement to make sure they are getting direct sources of long chain omega-3 fats. 

This is the case because very little of the ALA we eat converts to DHA. Some Vegans may do a good enough job to get some DHA in the brain. Others will grow very deficient making supplementation all the more important.7 

Finding the right fish oil dose 

If you opt out of the fish oil path and testing confirms you have adequate levels of omega 3, great. According to long time nutrition commentators like Dr. Barry Sears, the ratio of ARA to EPA that is optimal is somewhere between 1.5 – 4.

In these cases, there is no need to go any further, especially if you are feeling sharp and healthy.

However, if you test low, fish oil, as a bioavailable form of EPA and DHA, can start to look like an attractive option, but how much to take?

Many advocate for mega dosing fish oil, and it’s true that of the therapeutic applications for EPA and DHA have been discovered in higher dose pharmaceuticals. I would invite you to check out this episode of The Drive by Peter Attia at the 55 minute mark for a high level conversation about EPA / DHA and lipids.

Does it follow that the average Joe should go out and take 10 + grams of fish oil a day?

As with anything, I’m sure it depends on the individual. Fish oil is a blood thinner and some people develop side effects when taking high doses. In the Vascepa trial, the group given the EPA drug had higher incidents of “serious bleeding events.” Not everyone will tolerate a lot of fish oil.  

I find tremendous benefit from taking 2-3 days consecutive of about 600mg and 425mg of DHA:EPA.

I notice a calming effect and increased cognitive function, however, if I up the dose, I develop side effects reliably, the primary one feeling a little light headed. I also find that more than a few days at this dose is sub optimal for me as well. Taking too much fish oil, especially cod liver oil which is rich in Vitamin A, K and D can cause unwanted side effects, dizziness being a common one. 

Taking small doses and skipping multiple days a week is the best bet for me. This is essentially the regimen outlined by longevity researcher Valter Longo in his book The Longevity Diet. Longo recommends a fish oil capsule, but only a couple times a week. 

One of the benefits of buying bottled fish oil, as opposed to fish oil capsules, is it’s easier to create a custom dose based on what works best for you. 

Are you taking fish oil?

At what dose and why? 

John O'Connor

John O'Connor is the founder of Gene Food, host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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