Fish oil with high EPA stimulates muscle building

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Athletes who want to build muscle mass can use not only proteins, creatine and amino acids, but also fish oils to achieve this. The anabolic effect of omega-3 fatty acids has been confirmed, so now molecular scientists at the University of Aberdeen have gone a step further. They are about to publish the results of a study in Biochemical and Biophysical Research Communications from which you can deduce which fish oil supplements have the strongest anabolic effect: those containing lots of EPA.

Taking fish oil supplements or eating a diet that is rich in fish fatty acids have a body recompositioning effect: your fat mass decreases and muscle mass increases. Scroll down to find links to articles on the anabolic and fat-cell killing effect of fish fatty acids.

Researchers in Aberdeen, Scotland, were curious about how fish fatty acids can have an anabolic effect, so they designed experiments with full grown C2C12 muscle cells from mice to try and work out the mechanism involved. They exposed the cells in test tubes to 50 micromols of the fish fatty acids DHA and EPA, and stimulated anabolism with leucine.

When the researchers measured the build-up and breakdown of muscle cell protein, they noticed that these were 25 percent higher and 22 percent lower respectively in the muscle cells that had been exposed to EPA.

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The researchers then looked at the activity of anabolic signal molecules in the muscle cells. The figure below shows that EPA and DHA both activated p70s6k, but only EPA activated FOXO3a. The fish fatty acids had no effect on the other signal molecules that the researchers examined: Akt, mTOR, 4EBP1 and rps6.

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“Fish oil supplementation containing a higher proportion of EPA than DHA could be the most efficacious in improving protein accretion in response to anabolic stimuli such as L-leucine/resistance exercise and could attenuate protein breakdown in ageing skeletal muscle”, the researchers conclude. “Further work in humans is clearly required to test this hypothesis.”

Biochem Biophys Res Commun. 2013 Mar 22;432(4):593-8. doi: 10.1016/j.bbrc.2013.02.041. Epub 2013 Feb 21.

The effect of eicosapentaenoic and docosahexaenoic acid on protein synthesis and breakdown in murine C2C12 myotubes.
Kamolrat T, Gray SR.

Source

Musculoskeletal Research Programme, Institute of Medical Sciences, University of Aberdeen, AB25 2ZD, UK.

Abstract

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been found to stimulate protein synthesis with little information regarding their effects on protein breakdown. Furthermore whether there are distinct effects of EPA and DHA remains to be established. The aim of the current study was to determine the distinct effects of EPA and DHA on protein synthesis, protein breakdown and signalling pathways in C2C12 myotubes. Fully differentiated C2C12 cells were incubated for 24h with 0.1% ethanol (control), 50?M EPA or 50?M DHA prior to experimentation. After serum (4h) and amino acid (1h) starvation cells were stimulated with 2mM l-leucine and protein synthesis measured using (3)H-labelled phenylalanine. Protein breakdown was measured using (3)H-labelled phenylalanine and signalling pathways (Akt, mTOR, p70S6k, 4EBP1, rps6 and FOXO3a) via Western blots. Data revealed that after incubation with EPA protein synthesis was 25% greater (P<0.05) compared to control cells, with no effect of DHA. Protein breakdown was 22% (P<0.05) lower, compared to control cells, after incubation with EPA, with no effect of DHA. Analysis of signalling pathways revealed that both EPA and DHA incubation increased (P<0.05) p70s6k phosphorylation, EPA increased (P<0.05) FOXO3a phosphorylation, with no alteration in other signalling proteins. The current study has demonstrated distinct effects of EPA and DHA on protein metabolism with EPA showing a greater ability to result in skeletal muscle protein accretion.

PMID: 23438435 [PubMed – in process]

Source: http://www.ncbi.nlm.nih.gov/pubmed/23438435