Omega-3 help reduce weight in obese mice

A high-fat diet supplemented with EPA (eicosapentaenoic acid) has been shown to reduce the weight of obese laboratory mice. Moreover, this  omega-3 appears to reduce both the size of adipose tissue cells and its inflammation.

This was revealed by researchers at Texas Tech University in Lubbock (USA) in a study published in the Journal of Nutrition. 

Obesity: more than just a weight problem

Obesity represents one of the main global public health problems: its prevalence is steadily and worryingly increasing in Western countries as well as low- and middle-income countries. Obesity is associated with increased adipose tissue, the primary lipid storage in humans, consisting of numerous cells called adipocytes. The condition is characterized by increased blood pressure, blood sugar, and inflammation. Therefore, it is an important risk factor for various chronic diseases such as type 2 diabetes, cardiovascular diseases, and cancers. Research aimed at developing nutritional interventions to prevent or treat obesity and its associated diseases is urgently needed. The same Texas scientists previously demonstrated EPA omega-3's ability to reduce insulin resistance and inflammation in obese laboratory mice.

EPA reduces macrophages, inflammatory cells

The study analyzed adipose tissue taken from animals subjected for eleven weeks to different diets: one group followed a low-fat diet, another a high-fat diet, and a third a high-fat diet containing EPA. Finally, a group was fed a high-fat diet for six weeks followed by EPA supplementation for only five weeks. Data analysis showed that, compared to mice fed a high-fat diet alone, the diet combined with EPA caused decreases in body weight, fat amount, adipocyte size, and also showed less macrophage infiltration in adipose tissue—immune cells indicating inflammation. 

Conversely, no significant differences emerged between mice fed a high-fat diet and those given the same diet followed by EPA supplementation for six weeks. However, this second group showed reduced average adipocyte size and macrophage infiltration, suggesting that EPA could prevent adipose tissue inflammation and growth, typical features of a lipid-excess diet. Metabolomic analyses of adipose tissue and bioenergetic tests also indicated that EPA may regulate mitochondrial function, the cellular organelles responsible for energy production.

EPA counters the effects of a high-fat diet 

According to the researchers, these data demonstrate that EPA supplements can improve the harmful effects of excess lipids by increasing oxygen consumption and fatty acid oxidation, reducing adipocyte size, and decreasing adipose tissue inflammation. Further studies will be necessary to clarify the cellular signaling mechanisms and those mediating EPA’s effects. 

 Source: Monique J LeMieux, Nishan S Kalupahana, Shane Scoggin, and Naima Moustaid-Moussa “Eicosapentaenoic Acid Reduces Adipocyte Hypertrophy and Inflammation in Diet-Induced Obese Mice in an Adiposity-Independent Manner” J. Nutr. 2015 jn.114.202952; first published online December 31, 2014.