Polyunsaturated fatty acids (PUFAs) play wide-ranging roles in cell metabolism, signaling, and inflammation. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are found primarily in fish and have key roles in metabolism and inflammation. EPA reduced triacylglyceride formation and improves blood lipid profiles 1. DHA enhances lipid oxidation and insulin sensitivity in skeletal muscle 2. Combinations of omega-3 are commonly consumed and shown to increase fat oxidation, reduce body weight, and prevent weight gain 3,4.
Conjugated linoleic acid (CLA), a PUFA found in grass-fed beef among other sources also plays a role in lipid metabolism 5. CLA is purported to suppress appetite, increase fat mobilization, and increase fatty acid oxidation 5. In addition, CLA is purported to reduce fatty acid synthesis in adipocytes, suggesting that CLA discourages fat deposition directly contributing to body composition 6.
Clinically, mitochondrial dysfunction is associated with reduced capacity for fatty acid oxidation and inversely related to the incidence of type II diabetes and obesity 7. The role of PUFAs such as omega-3 and CLA in glucose metabolism and cellular uptake is not well understood. Glucose transporter 4 (GLUT4) is an insulin-dependent glucose transporter found almost exclusively in skeletal muscle and adipocytes. Enhanced GLUT4 expression is evident of increased glucose uptake and glycolytic reliance 8. There is limited evidence investigating the effects of omega-3 fatty acids and CLA on human skeletal muscle cell metabolism.
The research . . .
Muscle cell metabolism can also play a significant role in body composition. Recently, a study was undertaken to investigate the effects of a combination of DHA and EPA (combination omega-3) and CLA on oxidative and glycolytic capacities and related gene expression, as well as mitochondrial biosynthesis 9. This study was conducted on human muscle cells.
The results . . .
Omega 3 significantly encouraged metabolic genes as well as oxidative metabolism (oxygen consumption), glycolytic capacity, and metabolic rate compared with control. Both treatments (omega-3 and CLA) significantly increased mitochondrial content.
Important points . . .
This work identified several effects that omega-3 fatty acids EPA and DHA, as well as CLA, have on metabolism and mitochondrial characteristics in human muscle cells.
Omega-3 treatment significantly increased basal oxidative metabolism as well as basal and peak glycolytic metabolism. This likely results in greater glucose uptake which is supported by up-regulation of the GLUT4 transporter.
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