Fish oil has become a fairly standard dietary supplement in the last few years, particularly for its cardiovascular benefits. My goal in this post is not to analyze those studies, but rather to consider the nuts and bolts of extracting genuine benefits from fish oil, based on my own readings on the topic. I’m not an expert, obviously, just a curious layman.

First: Dosage.

Not too long ago, Dr. Davis, the Heart Scan Doc, wrote a very helpful post on getting your dose of fish oil right. In essence, you need to look at the EPA and DHA numbers, add them together, then multiply that sum by the servings of capsules that you take per day. Dr. Davis writes:

What should the total daily dose of EPA + DHA dose be? That depends on what your goals are.

If your goal is to modestly reduce the risk of dying from heart attack, then just eating fish a couple of times per month will begin to exert an effect, or just taking a dose of 300 mg EPA + DHA per day from a low-potency capsule will do it. However, that’s an awfully unambitious goal.

Our starting omega-3 dose in the Track Your Plaque program has, over the years, increased and now stands at 1800 mg EPA + DHA per day. However, the dose for 1) full reduction of triglycerides and/or triglyceride-containing abnormal lipoproteins, 2) reduction of Lp(a), and 3) the ideal dose for coronary and carotid plaque control are substantially higher.

I’ve spent way too much time in Whole Foods examining the labels of various kinds of fish oil. My conclusions are two: (1) the EPA + DHA of many fish oils is shockingly low and (2) the total EPA + DHA varies wildly independent of price. The highest numbers I’ve seen so far are in the ProOmega fish oil sold by Dr. Eades. It has 450 mg DHA and 650 EpA per two-capsule serving. (Nope, I don’t benefit from sales of that in the slightest.)

Second: Storage.

In addition to EPA + DHA content in your fish oil, you should worry about the strong possibility of rancid fish oil. Here’s what Dr. Eades says about the danger:

Fish oil is primarily EPA and DHA, both of which are extremely unsaturated. And, as we all know, the greater the degree of unsaturation, the greater the propensity to go rancid. When these oils go rancid (or “go off” as the Brits put it) they don’t go from being healthful to simply becoming neutral, they actually convert to harmful oxidized fats called lipid peroxides.

Lipid peroxides can (and do) start free radical cascades that can damage fatty cellular membranes. At the very least lipid peroxides consume the body’s stores of vitamin E and other antioxidants to neutralize them, leaving the body short of many of its natural defenses.

You can prevent it by taking some simple steps. Dr. Eades writes:

How do you insure that the fish oil you get is not rancid? It’s actually pretty easy.

First, purchase the freshest fish oil capsules you can find. Take them home, and if they are in plastic bottles, put them in glass bottles. Plastic bottles, surprisingly enough, are not totally impervious to air. Glass bottles are impervious to air. Most fish oil is encapsulated using gel caps, which are also not impervious to air. You can’t really reencapsulate the fish oil, so you’ve got to live with the gel caps, but putting them into a glass bottle keeps the air from getting to the gel caps in the first place.

Second, put the glass bottle in the refrigerator. The cold will markedly slow down the oxidation process even if a little air gets in the bottle. Refrigerated fish last a lot longer than fish left out on the counter.

The final step you can take to insure freshness of your fish oil capsules is to bite into one and chew it. If it is rancid, you’ll know it. If it is, throw the whole batch out. If you perform the chew test every four or five days, you’ll always know you’re taking unrancid fish oil.

I keep my fish oil in the fridge, but I ought to transfer it to a glass jar. I should also make a habit of doing a chew test once a week. That sounds icky, but I will hope that fish oil is only disgusting when rancid. After all, I have no problem taking my spoonful of straight cod liver oil each day, also kept in the fridge, along with the butter oil. Now that I consider the matter, however, it would be easier (and likely cheaper) to switch to the liquid form of fish oil — like Nordic Naturals Omega 3D — once I used up my current supply of capsules.

Third: Ratios

From what I’ve read, the critical issue with omega-3 fatty acids is not your absolute intake, but your omega-6 to omega-3 ratio. Stephan of Whole Health Source argues — and rightly so, I think — that a healthy omega-6: omega-3 ratio is somewhere between 2:1 and 1:4. By way of contrast, the ratio in the American diet today is around 16:1.

As the charts in Stephan’s post show, limiting your omega-6s requires avoiding vegetable oils, except palm and coconut oil. Animal fats are far preferable — particularly beef, lamb, and pork fat rather than chicken and turkey fat. In practical terms, that requires strictly limiting conventionally-prepared fried foods, mayonnaise, salad dressings, and the like found in grocery stores and restaurants. If you’re willing to take a bit of trouble, however, you make and enjoy healthy versions of these foods at home using good fats.

If you’d like to know more about omega-3 and omega-6 fats, I recommend Stephan’s whole series on the subject, to which I’ve linked before:

• Vegetable Oil and Homicide
• The Omega Ratio
• Omega-3 Fats and Brain Development
• Omega Fats and Cardiovascular Disease
• A Practical Approach to Omega Fats

Fourth: Supplements in General

Finally, I’d like to recommend Richard Nikoley’s post on diet supplements. (That’s a link to Part 4, but he summarizes and links to the prior parts in the introduction.) I agree with his general principle that “supplementation ought to be the exception, not the rule, and there ought to be clear reasons for supplementing.” I also think his particular recommendations of Vitamin D (in the form of D3), fish oil, and K2 (whether via butter oil or in a synthetic form) are very sensible.