Sorting out the why, when, what, and how of fish oils is a mind-bending labyrinth of obfuscation. So-called ‘whole food’ fish oil supplements are far from whole and certainly not foods. Yet the right stuff is crucial for many aspects of good health. Here are some thoughts to guide you in deciding what to do about fish oils.
By the way, the ultimate test of whether a fish oil supplement is beneficial is what response your body has to it. Examples of what to look for are toward the end of this post.
Manna from the Sea
The overwhelming amount of information flowing in on fish oil research is that fish oils are super important for good health. Although the research publications themselves are pretty calm, the marketing claims derived from them are nothing short of miraculous.
Let’s just bypass the massive amount of information on that topic, since is it so widely covered elsewhere. Just accept that you can be healthier in many ways with a daily dose of the right fish oils.
Now let’s get down to some of the fishiness in this fish oil business.
Focus on DHA
Very few articles on the internet, including almost none of the sites that market fish oil supplements, make it clear what is meant by ‘fish oils’ in the first place.
For the sake of simplicity, let’s just focus on DHA. This is the most important of the two main components of fish oil (EPA being the other one). Let’s narrow it down even further by zeroing in on DHA regarding brain health. After all, DHA is the core substance that underlies the historical knowledge about fish being brain food.
DHA is the most abundant omega-3 fatty acid in the human brain. It comprises about 40 percent of the polyunsaturated fatty acids (PUFAs) in the brain. DHA deficiency is associated with all kinds of cognitive decline.
The brain depends on DHA from outside sources. Our bodies do not make it, aside from an inefficient conversion from alpha-linolenic acid that we get in our diet from certain seeds (e.g., flax, hemp, chia, walnut). In other words, we have to get most of our DHA by consuming it.
When you read the label on any fish oil supplement, it should list the amount of DHA and the amount if EPA in the recommended daily dose.
What is often missing is WHAT FORM those fatty acids are in. This is potentially very important because not all supplements are alike, since not all forms of DHA are the same.
This is where arguments begin about what the best form is. Let’s take a look at what this means.
Descent into Biochemistry
This is important explanatory information. However, you can skim over it or even skip it entirely if your eyes begin to glaze over as you read it. I’ll understand.
DHA is short for docosahexaenoic acid, which tells chemists a few important things about its chemistry. The name itself refers to a molecule that is 22-carbons long, with an acid moiety on one end. We also know that it is an omega-3 fatty acid, meaning that the first carbon-carbon double bond starts at the third carbon from the non-acid end. In addition, DHA is remarkable for being highly unsaturated – it contains 6 carbon-carbon double bonds.
Here is what it looks like in diagram form as a ‘free’ (unattached) fatty acid. Note that I have labeled it ‘UNSTABLE’ because, as a free fatty acid with that many double bonds, it will oxidize very fast.
This is not the only form of DHA that can oxidize. However, information about oxidized products is nearly absent from the scientific literature. Here is one study that addresses it, though:
Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA. Scientific Reports 5 : 7928 (21 January 2015).
Just a quick peek under the hood at the end of this study finds the following commentary:
In summary, the majority of fish oil supplements available for purchase in New Zealand not only have n-3 PUFA contents well below those claimed by labels, but are also considerably oxidised (with PV, AV, and Totox values above recommended levels). The associated health implications are unclear. Future studies should investigate the effect of environmental conditions on oxidation of encapsulated fish oils, particularly regarding the oxidation process when supplements are stored in retail or home environments. Further, clinical trials investigating the health effects of fish oil products should measure and report their peroxide and anisidine values, so that the importance of oxidation to efficacy and harms can be better understood.
Basically, this survey of products undermines ALL clinical research on the health benefits of fish oil supplements. Isn’t that just special?
One of the Problems
Manufacturers go on and on about the best sources of ‘fish’ oils: algae, krill, bony fishes of many kinds, concentrated esterified fatty acids or triglyceride forms, etc., etc., ad nauseum.
Just look at one of the main debates, which centers on whether fatty acids such as DHA should be esterified (linked to an ethanol molecule) or in a triglyceride. Here is what folks are talking about in diagram form:
The key is that these forms are the result of processing – i.e., extracting, distilling, chemically modifying – the oils that actually occurred in the fish in the first place. They are supposed to be more stable than the DHA free fatty acid, although research is sparse on that point. Each one is also supposed to be more bioavailable than the other.
Claims about bioavailability depend on which source or form of fish oils a particular company is marketing. No surprise there.
The implication about bioavailability is that consumption of a particular supplement leads to its action in your body. This is a big assumption that is hardly ever supported by scientific evidence.
In fact, if fish oil supplements are as deficient worldwide as much as they are in that New Zealand survey cited above, then claims about bioavailability are just so much hooey.
The truth is that biochemists do not know how DHA or EPA, regardless of whether they are in esterified or triglyceride forms, are absorbed in the gut. However, since neither of these processed forms is a natural product, it is almost a certainty that they have to be ‘re-modified’ back into an acceptable form to be useful. Any such process introduces a level of inefficiency for accruing health benefits.
The good news is that some fish oil supplements are helpful. Without guidance by good science, though, the experiment that any consumer has to conduct has exactly one data point – i.e., herself or himself.
You know your body better than anyone else does. Based on that, you may see a clear result from taking fish oil supplements. A typical experiment, which my wife has conducted on herself, involves joint pain. When she takes a supplement regularly, her joints feel fine. When she doesn’t, after a while the pain starts to creep back. Many people have had the same experience.
In fact, relieving joint pain is one of the most common results that folks get from fish oil supplements. Many other results are possible. You just have to be able to have a ‘before’ and ‘after’ for comparison.
This is where brain health is trickier. Let’s say that you want to prevent Alzheimer’s Disease. This is clearly not a good indicator, since you probably won’t know the results until it is too late.
Fortunately, this is one issue that we can address based on recent scientific discoveries.
DHA in the Brain
Take a look at this quote from a recent review on this topic (Docosahexaenoic Acid (DHA): An Ancient Nutrient for the Modern Human Brain. Nutrients 3: 529-554 (2011)):
The brain is the most energy-demanding of all the human body organs, accounting for 2.3% of the total body weight but 23% of the body energy utilization in adults and 74% of the energy utilization in newborn term infants. The brain is a lipid-dense organ, second only to adipose tissue. Brain lipids are far more complex structurally and functionally. Indeed 60% of the dry weight of the brain consists of phospholipids.
Two important phospholipid subcategories, glycerophospholipids and sphingolipids, are critical elements of all cellular membranes but particularly membrane-rich tissue such as grey matter. Glycerophospholipids consist of a glycerol backbone with two fatty acid chains attached; a saturated fatty acid is usually found in the Sn-1 position, and an unsaturated fatty acid in the Sn-2 position. The Sn-3 position attaches a phosphate, bonded to a defining polar head group, such as choline, serine, ethanolamine or inositol. In the brain, the phospholipids with the highest content of DHA are the ethanolamine (PE) and serine (PS) glycerophospholipids (phosphoglycerides).
Two things about DHA stand out in this quote. The first is that DHA exists in the brain bound to phospholipids of type called phosphoglycerides. The name ‘phosphoglycerides’ tells us that each one contains a phosphate and a glycerol with one or more fatty acids attached to it.
Here is where it gets really interesting. Okay, at least interesting to geeks like me.
The most common type of phosphoglyceride containing DHA is one that has DHA itself attached in the middle of the glycerol molecule, with a saturated fatty acid at one end of the molecule and the phosphate group (usually bound to ethanolamine, serine, or choline) at the other end.
Diagrammatically (for all you visual learners), it looks like this:
In other words, DHA has to be at the middle (‘sn-2’) position, next to a saturated fatty acid and to a phosphate group. For super-geeky reasons, this has to be the case for DHA to function optimally in brain cell membranes.
EVEN BETTER … this abstract from some of the latest research on brain DHA adds some much appreciated clarity to how this crucial substance gets into brain in the first place. (I will explain what it means just below the abstract, if you want to skip over it. It is a crucial piece in the puzzle that adds a remarkable new insight into brain health. Trust me, it really does.)
Mfsd2a is a transporter for the essential omega-3 fatty acid docosahexaenoic acid. Nature 509(7501):503-6 (May 22, 2014).
Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is essential for normal brain growth and cognitive function. Consistent with its importance in the brain, DHA is highly enriched in brain phospholipids. Despite being an abundant fatty acid in brain phospholipids, DHA cannot be de novo synthesized in brain and must be imported across the blood-brain barrier, but mechanisms for DHA uptake in brain have remained enigmatic. Here we identify a member of the major facilitator superfamily–Mfsd2a (previously an orphan transporter)–as the major transporter for DHA uptake into brain. Mfsd2a is found to be expressed exclusively in endothelium of the blood-brain barrier of micro-vessels. Lipidomic analysis indicates that Mfsd2a-deficient (C-knockout) mice show markedly reduced levels of DHA in brain accompanied by neuronal cell loss in hippocampus and cerebellum, as well as cognitive deficits and severe anxiety, and microcephaly. Unexpectedly, cell-based studies indicate that Mfsd2a transports DHA in the form of lysophosphatidylcholine (LPC), but not unesterified fatty acid, in a sodium-dependent manner. Notably, Mfsd2a transports common plasma LPCs carrying long-chain fatty acids such LPC oleate and LPC palmitate, but not LPCs with less than a 14-carbon acyl chain. Moreover, we determine that the phosphor-zwitterionic headgroup of LPC is critical for transport. Importantly, Mfsd2a-knockout mice have markedly reduced uptake of labelled LPC DHA, and other LPCs, from plasma into brain, demonstrating that Mfsd2a is required for brain uptake of DHA. Our findings reveal an unexpected essential physiological role of plasma-derived LPCs in brain growth and function.
Translation: They found a protein (Mfsd2a) that transports DHA across the blood-brain barrier into the brain. The form of DHA is in a complex called lysophosphatidylcholine. As you can see below, it looks a lot like the phosphoglycerides that make up brain cell membranes, doesn’t it?
A key feature of this molecule is where the DHA is located in the complex … i.e., in the middle (sn-2) position.
BONUS THOUGHT … DHA in the sn-2 position in phosphoglycerides is the predominant form in mother’s milk. It is the form that is required for optimal brain development in nursing infants.
For those of us who are beyond that stage of life, Mother Nature has a wonderful source of just the right forms of DHA: FISH!
Woo-hoo! Now we are getting somewhere!
If you’ve stuck with me this far, here is what we have discovered in a roundabout way after looking at some geeky scientific stuff:
The best source of DHA is whole food – i.e., fish.
Fish oil supplements may or may not be helpful. I wouldn’t recommend against them. Even if they are helpful, they are highly inefficient in comparison with native forms of DHA that come neatly packaged in the source food. Yup, the DHA in whole fish is already in the forms that we can take advantage of directly.
Nutritionists are probably rejoicing over this one, since they have routinely recommended whole foods over supplements for many years. This time they are right.
Nevertheless, if you insist on taking fish oil supplements (which I still do), ignore the marketing hype about which one is best. Nobody really knows. What I do is select a liquid with a lot of DHA and EPA in it per teaspoon or tablespoon, keep it cold, and add it to veggie shakes.
The most important caution is to make sure that your supplement (or any kind of oil for that matter) does not oxidize … i.e., become rancid. You can smell rancidity (powerful ‘staleness’ odor) in a liquid easily. If you have softgels, chew one up now and again to check for rancidity. If you get the giant economy size jar somewhere (such as Costco in my neighborhood), keep it cold all the way to the last capsule.
Now About Those Fish
The oil content, and therefore the DHA content, varies a lot from one kind of fish to another. You can do some searching around for surveys to find good sources. The table below gives you a good idea of which fish to look for, though. One additional comment about DHA sources. Wild game meat or grass-fed beef are sometimes cited as a good sources. However, their content hovers around the bottom of this chart, among other non-fish sources.
DHA – A Step Toward Optimal Health
My views about fish oil supplements began to change over the past few months. During this period I discovered that my background in ‘solution’ biochemistry merely opened the door to understanding DHA. It turns out that ‘solid state’ biochemistry – aka, biophysics – is much more powerful in explaining what this molecule does. Its actions are more clearly viewed in terms of quantum mechanics. I have Dr. Jack Kruse to thank for this new clarity.
Reading what he has to say about achieving optimal health, not just regarding DHA, has been a wild ride and well worth it. I recommend this journey to everyone.
One of the most inspirational stories by a participant on Dr. K’s forum comes from a young lady by the name of Inger. Consuming whole food fish is just one of her steps toward a remarkable transformation in her health.
The key is that anyone can achieve such a transformation if they set their mind to it.
If you have a few minutes, take a look at what she has accomplished, here: Winter Solstice Special Blog: “The Inger Effect”
Then just imagine what is possible for yourself.
A Bonus for the Brave
Yup. You read that right. Doesn’t it make sense that raw fish, high in DHA in native forms would be the best source of this remarkable brain food?
Sushi would be fine (esp. tuna and salmon). Oysters on the half shell would be fine. However, if you are truly brave and really want to ramp it up, check out Inger’s mackerel head smoothies. I have to admit that, as of this writing, I haven’t partaken of this delicacy yet. Even mentioning it in my house attracts howls of derision.
Nevertheless, mackerel head smoothies are on my radar and I will be taking the leap on them before long.
Meanwhile, just to let you know that I am not kidding, Inger actually shows you how to make one (and drink it) in this video. It is phenomenal.
Things Just Get Better,