Fish Oil Affects Cortisol, Fat Mass
GETTYSBURG, Pa. – Consumption of fish oil supplements can positively affect lean body and reduced serum cortisol levels, according to a new study (J Intl Soc Sports Nutr. ePub 8 Oct 2010. DOI: 10.1186/1550-2783-7-31). Researchers from Gettysburg College recruited 44 healthy adults to examine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition and cortisol production. Subjects were randomized to receive either 4 g/d of safflower oil (SO) or 4 g/d of FO providing 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA) for six weeks.
At the end of the intervention, researchers found subjects taking FO had a significant increase in fat-free mass compared to the SO group; they also had a significant reduction in fat mass and a tendency for a decrease in body fat percentage. In addition, there was a tendency for salivary cortisol to decrease in the FO group, and a significant correlation in the FO group between the changes in cortisol and change in fat-free mass and fat mass. There were no significant differences between the groups in terms of body mass, RMR or respiratory exchange ratio.