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All about omega-3 fatty acids

chemical structure of eicosapentaenoic acid

Chemical structure of eicosapentaenoic acid (EPA) (Photo credit: Wikipedia)

What’s the deal with Omega-3 fatty acids? Why are they and why are they better than Omega-6 and Omega-9 fatty acids? These are some common questions I get on a daily basis. Read below to get an explanation. One warning though… i’m going to get a little more technical in this article than I have in the past.

Cell Membranes

The cells in our body are encased in membranes. These membranes keep the contents of our cells from spilling out and are composed of lipids (phospholipids, cholesterols, and other compounds). A phospholipid is composed of two fatty acid molecules

Fatty Acids

Fatty Acids (Photo credit: AJC1)

connected by a head group. Fatty acids are made of a carboxylic acid (the HO-O-C on the left above) attached to a long carbon chain (16 to 24 carbon atoms).  These carbon atoms are either connected with single (saturated) bonds or double (unsaturated bonds). Single bonds are the single lines in the picture above and double bonds are represented by the double lines.

Fatty acids from plants and animals are usually polyunsaturated fatty acids (PUFAs), meaning that they have three or more double bonds. These acids are named based on the location of the first double bond. Omega-3 fatty acids have their first double bond in the third from the end.  Omega-6 means the double bond is 6 from the end… and so forth. Most PUFAs from plant sources are omega-6, while PUFAs from cold water fish are usually omega-3. The main omega-3 PUFAs to know about are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid.

Why is this important for your health?

It turns out that humans cannot make omega-3 PUFAs, so their bodily supply is directly proportional to dietary intake. The more omega-3 PUFAs in your body, the more omega-3 PUFAs that can get incorporated into your cell membranes (meaning less omega-6 PUFAs and monosaturated fatty acids). If you have more omega-3 PUFAs in your cell membranes, many cellular functions will work better:

– Increased and more efficient cellular messaging, especially in your immune, blood and nervous systems (including the retina)

– Improved cardiovascular health by modulating calcium ion channels in cardiac tissue

– Reduction in pathological neovascularization in diseases such as diabetic retinopathy, age-related macular degeneration (AMD), and many forms of cancer

– Increases in retinal signaling by 3-5 times (when compared to the rate of cells with omega-6 PUFAs in their cell membranes)

The Brain

The central nervous system actively gathers DHA omega-3 PUFAs so that the percentage of DHA in the brain can be as high as 50% (compare this to the average of <5% DHA in other tissues). This is why infant formula and kids whole milk is fortified with DHA (to help developing brains grow properly).


Inflammation and oxidation are known to cause damage to the body and are suspected precursors to cardiovascular disease and eye diseases, such as macular degeneration. So limiting oxidation is key in preventing these conditions. It turns out that if you have a lot of omega-6 PUFAs in your cell membranes, those PUFAs can be broken down into pro-inflammatory byproducts and result in increased oxidation. If you have more omega-3 PUFAs, then this process is down-regulated, simply because there is less omega-6 PUFAs to convert into inflammatory substances.


Resolvins (such as RvE1 and RvD1) are molecules derived from the omega-3 PUFAs, DHA and EPA. Resolvins directly shut down the inflammatory cascade in your body. For example, when you take aspirin, it causes more resolvins (specifically RvE1) to form in your body, resulting in aspirin’s anti-inflammatory effect. The potential benefits of resolvins are so great that drug companies are even starting to create resolvin-based medications to treat dry eye (an inflammation-based condition), as well as AMD and diabetic macular edema.

The Bottom Line

Fish derived omega-3 PUFAs are likely beneficial for your health for many reasons and are being explored as a treatment for macular degeneration. See my previous post for the doses being used in current clinical trials.

(Note: I have no financial relationship to any of the commercial products described)


6 comments on “All about omega-3 fatty acids

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  2. mehdi.tavasoli
    October 11, 2013

    Hello!Dear thanks a million for the describtion. just i would like to know is omega-3 useful for growing hairs?

    • visionmd
      October 11, 2013

      I’m not sure. Maybe someone else who has read this knows??

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