Omega-3 Fatty Acids. I can write about this topic until my fingers are on fire; but what I want to talk about today is where the omega-3 in our seafood actually comes from… because it may not be what you think!
Going back to chemistry class: the term “omega-3” means that these molecules have a double bond on the 3rd carbon atom from the end of the chain. See the photos below? If you look from right to left, the first set of double lines (indicating a double bond) occurs at the 3rd point (each beginning and end of a line in this display represents a carbon atom).
And for bonus points, a “polyunsaturated” fatty acid, just indicates that molecule has more than 1 double bond :) You can probably guess what a “monounsaturated” fatty acid would be then? (If you actually read this, and reply back to this email with what you think a monounsaturated fatty acid must be based on what I’ve just told you, I have a special surprise for you)
There are various different types of omega-3 fatty acids. You may have heard of EPA, or DHA, but what about ALA?
ALA (alpha linoleic acid) is a shorter chain omega-3 fatty acid, with 18 carbons, and just 3 double bonds in its structure. ALA is found in seeds, nuts and oils. From ALA, our body can in turn, make EPA (a 20 carbon chain with 5 double bonds) and then DHA (a 22 carbon chain with 6 double bonds) through a molecular conversion process.
So why do we need to eat EPA and DHA from fish, if we can just eat ALA from plants?
Great question. Here’s a great answer.
All of the omega-3 fatty acids, ALA, EPA, and DHA are considered “essential”. That means our body cannot make it on its own, so we must EAT it.
However, the conversion from ALA (remember nuts, seeds, oils) to EPA, and then from EPA to DHA, is not so reliable. In fact, estimates of conversion are around only 15%! High saturated fat in our diet, and high omega-6 fatty acids in our diet (I’ll explain omega-6’s in a separate article), make it much more difficult to convert the ALA into the much needed EPA, and then the DHA.
So while you CAN get your EPA and DHA from ALA in plants only, it’s not the best way to ensure you are getting enough. The brain, eyes, and cell membranes NEED that DHA!
Back to fish. Fish cannot make their own omega-3 fatty acids either. They are just like us, they have to EAT it. So the omega-3’s that we seek, need, and enjoy from our fish, are actually coming from those fish EATING algae!
Algae is one of the only plants rich in EPA and DHA. But we would need to eat quite a bit of algae, or isolate that algae into supplemental form (and take enough capsules) in order to reap the benefits.
By eating fish, you are getting quality protein, quality fat, AND essential omega-3 fatty acids! Any time that you can use whole food to get in multiple healthy nutrients, it's a huge win.
Fun fact for the week - our omega-3’s we eat in fish, come from the algae the fish eat.