Using a murine model, researchers from Seoul National University, New Mexico State University and Florida State University sought to determine the effects of CLA, omega-3 and resistance training on muscle quality, as well as genes related to protein synthesis and degradation.
They randomly divided nine-month-old male mice into five groups: the first was placed on a normal diet, the second on a high-fat diet, the third was placed on a high-fat diet in conjunction with resistance training, the fourth consumed both a high-fat diet and CLA / omega-3, and the last consumed CLA /omega-3 while on a high-fat diet, in conjunction with resistance training.
After 20 weeks, the researchers observed that the grip strength of the high-fat diet group was considerably lower than that of the control group, but the mice in the other groups had greater grip strength than those in the high-fat diet group.
In terms of muscle quality, however, the group on a high-fat diet and resistance training programme fared better than those in the high-fat diet group and the group that had consumed CLA / omega-3 on a high-fat diet.
Furthermore, the muscle protein atrogin 1 was "significantly down-regulated" in the group that had consumed a high-fat diet and CLA / omega-3 while on a resistance training regimen, compared to the high-fat diet group and the group that had consumed a high-fat diet and CLA / omega-3.
At the same time, the expression of another muscle protein, MuRF1, decreased in the group on a high-fat diet and resistance training programme and the group that had consumed CLA / omega-3 on a high-fat diet and resistance training programme.
Don't resist the supplements
The researchers said high-fat diet-induced "gene expression involved in protein degradation was attenuated" after 20 weeks of resistance training and supplementation with CLA and omega-3.
In addition, resistance training led to improved muscle quality and grip strength regardless of CLA / omega-3 supplementation, though the results were better when supplementation was involved.
The researchers concluded that resistance training combined with CLA / omega-3 supplementation, even on a high-fat diet, "may improve muscle strength and quality by suppressing protein degradation", adding that "future research is needed to verify these findings in middle-aged obese men and women".
Source: Journal of Exercise Nutrition & Biochemistry
"Effects of conjugated linoleic acid/n-3 and resistance training on muscle quality and expression of atrophy-related ubiquitin ligases in middle-aged mice with high-fat diet-induced obesity"
Authors: Seung-Lyul Oh, et al.