Ahh, the Olympics. The time every two years that the world’s elite athletes get together to compete at the highest level while the rest of the world watches… from the couch. The demands of each event require that athletes develop their musculature in different ways – speed skaters are all thighs and skinny arms, figure skaters need to be as light and strong and flexible as possible, downhill skiers need extra mass to increase their velocity but need powerful legs to prevent them from crashing, and curlers… well, curlers look more like the rest of us. There are plenty of reasons why we (who do not get paid to exercise) should care about our own muscle mass. Having more muscle increases your metabolic rate, helps maintain overall health and metabolism, and looks better than having excess fat. As it turns out, there is some emerging literature about the effect of omega-3 fatty acids on muscle growth.
Gordon Smith and colleagues at Washington University in St. Louis, Missouri studied the molecular mechanisms that affect muscle growth in sedentary but healthy young individuals (n=9, 25-45 yrs) who were supplemented with 4 grams of EPA+DHA (ethyl ester) per day for 8 weeks (click here for the manuscript). Here are the basics:
- The study is small and there is no placebo control group. I want to say that upfront because this is more of a mechanistic study than an efficacy study. However, the authors took muscle biopsies, performed a hyperinsulinemic-hyperaminoacidemic clamp (which is pumping insulin and amino acids directly into the blood stream) pre- and post-supplementation, and analyzed endpoints at molecular, cellular and enzymatic levels. So, on the few study subjects they had, they looked at a lot of endpoints.
- Without insulin and amino acids on board, omega-3 fatty acids do not affect protein synthesis. Levels of protein synthesis were unchanged pre- and post-supplementation before any insulin or amino acids were introduced to the blood stream. The most basic part of protein synthesis is making sure the muscle has enough amino acids, building blocks of protein, to make more protein! Insulin is an anabolic hormone, meaning it causes our body to reduce protein degradation and, in general, increase in mass. In this anabolic environment, the researchers can look at molecular pathways to see if the machinery to make proteins has been increased. I do need to note that the high insulin-high amino acid state stimulating protein synthesis in muscle needs to be recreated in the real world by FIRST doing resistance exercise and THEN eating enough protein and carbohydrates to raise insulin and amino acid levels in the blood.
- Higher levels of omega-3 fatty acids in muscle cells enhanced muscle growth mechanisms in a high insulin, high amino acid environment. The muscle fatty acid profile in the subjects went from a EPA+DHA level of 2.57% of total fatty acids to 6.62%. We know from our research and red blood cell fatty acid profiles highly correlate with tissue levels of omega-3s, so we can assume that their Omega-3 Index was increased as well. The researchers found that the muscle protein fractional synthesis rate was increased when omega-3s were onboard, which means that there was more protein synthesis compared to breakdown in muscle specifically rather than whole body protein turnover. Getting a bit more molecular, the researchers found that the pathway that is known to regulate protein synthesis appeared to be 50% more active based on levels of phosphorylated proteins in the pathway (mTOR). Finally, muscle protein concentration and protein-to-DNA ratio was higher post-supplementation. So, in addition to the high insulin and high amino acid levels, having a higher amount of omega-3 fatty acids in the muscle cell seems to prime the machinery for protein synthesis. The reasons for this effect are still unknown.
For building muscle and maintaining a healthy weight, exercising and getting enough calories (both protein AND carbohydrates) to maintain the exercise is first and foremost. However, having higher levels of omega-3 fatty acids in the muscle cell may enhance the muscle growth. So, if you are still on your New Years Resolution to hit the gym, raising your Omega-3 Index may help in the effort.