Resistance training builds muscle mass and strength by promoting muscle growth, increasing muscle fiber size, and enhancing the body’s ability to generate force. A recent study shows that omega-3 fatty acids enhance the effects of resistance training on strength gains. Healthy young adults who took fish oil supplements – which are rich in omega-3s – while engaging in a resistance training program showed greater strength gains than those who took a placebo.

The study involved 28 healthy young adults who engaged in a 10-week resistance training program. Half of the participants took 4.5 grams of fish oil per day (providing 2.275 grams of EPA + 1.575 grams of DHA), while the other half took a placebo. Before and after the intervention, they measured the participants' blood omega-3 concentrations. Using the one-repetition maximum (1RM) method, they also assessed the participants' gains in absolute strength (the total amount of weight lifted ) and relative strength (the comparison of a person’s lifting capacity to their body weight).

They found that blood omega-3 concentrations increased by 109 percent among the participants who took fish oil, but increased by only 1.3 percent among those who took the placebo. Both groups showed similar increases in lean body mass and decreases in fat mass and body fat percentage. However, those who took the fish oil showed considerable absolute and relative strength gains in the 1RM bench press compared to the placebo group. Absolute strength increased by 17.7 percent in the fish oil group versus 9.7 percent in the placebo group, and relative strength increased by 17.6 percent versus 7.3 percent. Absolute strength gains in the 1RM squat were similar between groups, at 28.8 percent versus 20.5 percent; however, relative strength gains for the 1RM squat were higher in the fish oil group, at 29.3 percent versus 17.9 percent.

These findings suggest that fish oil supplementation during resistance training enhances muscle strength gains. The study investigators posited that these improvements were due in part to enhanced muscle protein synthesis, aligning with other research demonstrating that fish oil supplementation induced a 50 percent increase in muscle protein synthesis.

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• Learn more about factors that influence muscle protein synthesis in this episode featuring Dr. Stuart Phillips.

Coming soon: Our next FMF episode will feature Dr. Chris McGlory (one of the authors of this study), whose work focuses on the effects of omega-3 fatty acids on muscle protein synthesis.