Animal study shows positive effects on muscle cells’ sensitivity to "sugar hormone"
by Craig Weatherby
A research team based at the Université Laval in Montreal reports that marine omega-3 fatty acids from fish oil can increase muscle mass in cattle. While the results remain to be replicated in humans, these preliminary results are encouraging.
Most of us associate insulin with controlling blood sugar (glucose) levels, since the hormone is needed in order for cells to absorb glucose.
Adult onset diabetes occurs when our cells become “resistant” to the effects of insulin. When this happens, cells no longer absorb enough blood sugar (glucose) when insulin is released in response to consumption of sugars and starches.
But insulin also plays a role in maintaining muscle mass. And the new research results suggest that the hormone may help build muscle, too.
Increasing insulin resistance in aging muscle cells explains, in part, why people’s ability to convert food into muscle declines with age.
Omega-3 fatty acids are known to enhance glucose (blood sugar) metabolism in people and animals showing insulin resistance.
They’re also proven to prevent breakdown of muscle (catabolism), but the evidence for their ability to enhance anabolism—the process by which the body builds muscle—is less clear, so a team of American and Canadian researchers decided to test omega-3s in cattle.
They added supplements containing either omega-3s from fish oil or a mixture of cottonseed and olive oils without omega-3s to the regular diet of male cattle.
After five weeks, animals eating the omega-3-supplemented diet showed increased sensitivity to insulin which, in turn, improved protein metabolism. Twice the amount of amino acids was used by their bodies to make new proteins, especially in muscles.
If these results are confirmed in human trials, increased intake of marine omega-3s could help prevent the loss of muscle mass in older people and prevent the various health problems associated with it, including loss of stability when standing or walking.
And omega-3s might also help athletes trying to increase their muscle mass. But, as lead researcher Carole Thivierge noted, “...it should not be seen as a miracle product. For increased muscle protein metabolism to take place in people younger than 50, physical training is still required.”
- Université Laval, Montreal Canada. Study shows marine omega-3 fatty acids have positive effect on muscle mass. Accessed online May 9, 2007 at http://www.eurekalert.org/pub_releases/2007-05/ul-ssm050907.php
- Fujita S, Rasmussen BB, Cadenas JG, Grady JJ, Volpi E. Effect of insulin on human skeletal muscle protein synthesis is modulated by insulin-induced changes in muscle blood flow and amino acid availability. Am J Physiol Endocrinol Metab. 2006 Oct;291(4):E745-54. Epub 2006 May 16.
- Chow LS, Albright RC, Bigelow ML, Toffolo G, Cobelli C, Nair KS. Mechanism of insulin's anabolic effect on muscle: measurements of muscle protein synthesis and breakdown using aminoacyl-tRNA and other surrogate measures. Am J Physiol Endocrinol Metab. 2006 Oct;291(4):E729-36. Epub 2006 May 16.