Dietary fish oils limit adipose tissue hypertrophy in rats

Total body mass, fat pad mass, and fat cell size were examined after feeding rats diets containing 20% triglycerides from fish oil or lard. Although food consumption, weight gain, and fat balance on the two diets were similar, lard-fed rats had 77% more fat in perirenal fat pads and 51% more fat in epididymal fat pads compared with fish oil-fed rats. There was no difference between the two groups in fat cell number in each region; however, adipocytes were significantly smaller in fish oil-fed rats. Thus dietary fish oil appears to limit triglyceride accumulation in adipose tissue and thereby limit fat cell trophic growth.