We often think of omega-3 fatty acids as being good for the heart and immune system, but omega-3 may also play an important role inbody composition.

But what are fatty acids?

Fatty acids are long chains of carbon and are classed as either saturated, monounsaturated or polyunsaturated. Omega-3 and omega-6 are also “essential” fats because your body cannot make them so they can only be utilised through food or supplementation.

Omega-3 fatty acids primarily come from fish like salmon, mackerel and tuna (in their EPA and DHA forms) and also in lesser amounts from walnuts and flaxseeds (in their ALA form).

Protein synthesis basics

Whole-body protein turnover is the continuous process within the human body by which protein is created (anabolism) and broken down (catabolism). It is believed to occur at a rate of 300g/day in an average 70kg man. Gains in skeletal muscle occur following prolonged periods of net protein deposition; where muscle protein synthesis exceeds net muscle protein breakdown, thus resulting in a net gain in muscle protein.

Humans, especially athletes, often seek net gains in muscle protein which allows for more effective increases in muscle mass and enhanced muscle recovery. A number of nutritional and hormonal factors regulate protein synthesis and thus have a significant impact on body composition.

Omega-3 and its role in protein synthesis

Recent studies have suggested that long chain omega-3 fatty acids enhance the efficiency and effectiveness of insulin pathway signalling, therefore generating mTOR (mammalian target of rapamycin) activity. The mTOR regulates a number of physiological components including protein synthesis. Signalling through the mTOR is activated by amino acids, insulin and growth factors and is impaired by deficiencies in nutrients or overall energy.

Omega-3 is a helpful trigger for the endgoal of stimulating protein synthesis. The mTOR regulates protein synthesis and mTOR signalling is activated by insulin which is enhanced by omega-3 fatty acids.

In a study of fish oil supplementation (4g/day), nine healthy middle aged subjects were observed over an eight week period. The study revealed that the anabolic response to insulin and amino acid infusion was greater in those subjects who were supplementing with fish oil. In addition, muscle protein concentration and muscle cell size were both greater after fish oil supplementation which clearly demonstrates that fish oil aids the activation of mTOR.

This apparent activation of the insulin signalling pathway is thought to derive from the anti-inflammatory effects of long chain omega-3 fatty acids. Insulin resistance is associated with chronic inflammation and both EPA and DHA exert significant anti-inflammatory effects and actively reduce inflammatory signalling molecule production.

How does this benefit an elite athlete and how much of an impact does supplementing omega-3 really have?

Supplementing omega-3 fatty acids increases insulin sensitivity which allows for more effective activation of the insulin signalling pathway, ultimately leading to mTOR stimulation and muscle protein synthesis. It must be noted that increasing insulin sensitivity also has a significant effect on a number of other physiological functions, including increasing glucose and fatty acid uptake by muscle cells. This means that nutrients are directed to muscle cells for oxidation rather than being used for fat storage; improving overall body composition and providing more fuel for the muscles during exercise.

Article by Matt Jones, MSc Nutrition