The Impact of Dietary Omega-3 Polyunsaturated Fatty Acids on Energy Balance

PI: Mario Kratz PhD

The epidemic of obesity in the US has led many to advocate for a significant reduction in dietary fat intake.  However, over-emphasis on this recommendation may lead to an unexpected consequence of reducing the intake of beneficial fatty acids. A number of animal and human studies have shown that a diet rich in n-3-polyunsaturated fatty acids (n-3-PUFA) is beneficial because it lowers serum leptin concentrations and body fat mass. These studies have been predominantly done in animals, were of short duration, and have demonstrated diverging effects of n-3-PUFA on circulating leptin levels and leptin signaling in the central nervous system. There is a paucity of data on the metabolic mechanisms by which high n-3-PUFA diets might lead to the reduction of body fat mass in humans. The purpose of this  study is to compare the effects of a 4-month ad libitum diet rich in n-3PUFA and a control diet rich in monounsaturated fatty acids (MUFA) on body weight, fat mass, leptin levels and leptin sensitivity in overweight men and women. Secondary endpoints will be plasma concentrations of other adipokines and inflammatory cytokines, as well as the adipose tissue expression of genes involved in body weight regulation and inflammation.

The study has been completed in 2007; laboratory analyses of plasma, urine, and adipose tissue samples will continue in 2008 and 2009.

Kratz M, Swarbrick M, Callahan HS, Matthys CC, Havel PJ, Weigle DS. Effect of n-3-polyunsaturated fatty acids on plasma total and high-molecular weight adiponectin concentrations in overweight to moderatley obese men and women. American Journal of Clinical Nutrition 2008; 87: 347-53