Research Review: Omega-3s help protein synthesis | Precision Nutrition

Research Review: Omega-3s help protein synthesis

By Helen Kollias, Ph.D.


Omega-3 fatty acids are important for overall health — including helping us build bigger muscles by improving protein synthesis.

My nearly two-year-old daughter is asking for her “deeacheh.” Again. She’s licked the spoon clean from her daily dose of berry-flavoured DHA (a type of omega-3 fatty acid).

Mommy. De-ach-eh.

Giving her omega-3 fatty acids to help her brain development seemed like a good idea until she started outsmarting me.

Last night she figured out that screaming directly into her baby monitor makes mommy run in really fast to see what’s going on.

I open the door to see her looking over at me with a very satisfied look on her face. She’s standing over the monitor that is on a nightstand, behind a Kleenex box and across the room from where I last left her. Success!

I’m just waiting for a “10-4 mommy” over the monitor just before some kind of Great Escape.

Why fat is important

In the decade of big hair and bigger shoulder pads the 80s were also big on low-fat or even better no-fat. Fat was bad and hair spray was essential.

Now we know better: Some fats are essential, and hair spray has its problems.

Fat actually does things in your body. Important things that let you live. Some major functions of fat include:

  • providing energy
  • carrying fat soluble nutrients like vitamin E
  • helping with hormone synthesis and signalling
  • making up your cells’ membranes
  • making up your brain and much of your nervous sytem

Fat types

There are three major types of fat that occur in nature:

  • saturated
  • monounsaturated
  • polyunsaturated

A fourth type of fat, trans fat, appears naturally in small amounts. Any industrially created versions should be avoided.

All naturally occurring fats are important. For more on fats, check out:

Fatty acids

Dietary fats and oils are made up of fatty acid molecules. Three fatty acids plus a glycerol molecule makes a fat molecule (aka triglyceride).

Polyunsaturated fatty acids (PUFAs) include omega-3 fatty acids, omega-6 fatty acids and omega-9 fatty acids.

Out of polyunsaturated fats comes a further subgroup: essential fatty acids. Essential fatty acids are two specific types of omega-3 and -6 fatty acids: alpha-linoleic acid (ALA) and linoleic acid, respectively. They are essential because your body needs them, and can’t make them from other fats.


Omega-3 fatty acids seem to be the most important of the fatty acids, but this is probably because most of us don’t eat enough omega-3 fatty acids in our daily diets.

Omega-3 fatty acids do many good things in our bodies, including:

  • reducing inflammation
  • reducing cardiovascular disease
  • improving insulin sensitivity (great news for type II diabetics)
  • improving cognitive (brain) development

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) seem to be the most biologically important omega-3 fatty acids. ALA can be converted into EPA, and EPA can then be converted into DHA, but it seems your body can’t make a lot of DHA.

Fish oil

Where does fish oil fit in? As the name suggests, it’s oil from fish, in the same way that olive oil is oil from olives. Generally, fish oil you get from the store comes from oily fish like anchovies, mackerel or sardines. Fish oil is special — it’s a good source of EPA and DHA.

For more on this, see:

Research question

Protein synthesis is the process of (re)building new proteins from amino acid “building blocks”. Protein synthesis is an important part of building lean mass — for instance, in bone and muscle tissue.

This week I’m reviewing two studies done by the same researchers looking at omega-3 fatty acids. Can o-3 supplementation help us build bigger muscles by affecting protein synthesis?

Smith GI, Atherton P, Reeds DN, Mohammed BS, Rankin D, Rennie MJ, Mittendorfer B. Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr. 2011 Feb;93(2):402-12. Epub 2010 Dec 15.

Smith GI, Atherton P, Reeds DN, Mohammed BS, Rankin D, Rennie MJ, Mittendorfer B. Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia-hyperaminoacidaemia in healthy young and middle-aged men and women. Clin Sci (Lond). 2011 Sep 1;121(6):267-78.


In these two studies, researchers studied the effects of omega-3 supplementation on protein synthesis in people ranging from 40s to 70s.

Measuring protein synthesis

How the heck do you measure muscle protein synthesis?

By intravenously giving a specific amino acid (phenylalanine) with one slightly heavier hydrogen that lets you track the amino acid you’ve added. Think of it as a little flag on your amino acid. By tracking how quickly the flagged phenylalanine (and its byproducts) move throughout the body, you can estimate the rate of protein synthesis.

Insulin and other unlabelled amino acids were also infused to make sure that insulin and amino acids weren’t limiting protein synthesis.

Omega-3 supplementation

Total omega-3 supplementation was 4 g of Lovaza/day, which contains 1.86 g EPA and 1.50g of DHA for 8 weeks. By the way, Lovaza is produced by a pharmaceutical company, and requires a prescription.

The two studies are pretty much the same with two important differences:

  • age of the volunteers; and
  • using corn oil (an omega-6) as a placebo.

In the first study, the average age of the volunteers was 71, and half the volunteers got corn oil (omega-6) supplements instead of omega-3s. In the second study, subjects were on average 40 years old, and got no placebo.


In the first study using older volunteers, omega-3 supplementation increased protein synthesis rates more than corn oil (when given insulin and amino acids).

Great, but does this only happen in older adults who have more inflammation and are anabolic resistant (in other words, who don’t respond as strongly to anabolic stimuli like more dietary protein)? And could the results really mean that corn oil depresses protein synthesis (instead of meaning that omega-3s improve it)?

In the second study with younger volunteers (40 years old) and no placebo, the results were the same – increased protein synthesis.


Omega 3 fatty acids, at 4 g/day, improved muscle protein synthesis in older and younger volunteers after 8 weeks of supplementation while insulin and amino acids were given intravenously.

After the original study was done, everybody concluded that somehow the affect of omega-3 fatty acids on protein synthesis in older adults had to be indirect.

Older adults tend to have more inflammation and are less sensitive to amino acids so it made sense that omega-3 fatty acids would reduce inflammation and increase sensitivity to amino acids, and that would increase protein synthesis. But the second study challenged that idea.

Since younger adults shouldn’t have that much inflammation, and they shouldn’t be resistant to amino acids, then supplementing with omega-3 fatty acids shouldn’t increase protein synthesis, based on the conclusions from the first study, but it does.

A more practical question is: Does increased protein synthesis in these studies mean more slabs of muscle?

Hard to say, since there was no exercise in these studies, so this is without any exercise effect. And without infusion of insulin and amino acids there was no effect of omega-3s.

It’s going to take few more years to figure out whether omega-3 fatty acids really can help you gain muscle, but with so many other known benefits, omega-3s are worth taking anyway.

Bottom line

Take omega-3 fatty acids. They decrease inflammation, prevent cardiovascular disease, improve brain function and immune health, and now they might even help you gain muscle by increasing muscle protein synthesis.

And for all the Scrawny to Brawnies out there: Listen to Coach Paul and Coach Chuck when they tell to take your fish oil.

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