MONDAY DEC 24, 2007 (Foodconsumer.org) -- Omega-3 rich fish oil could help boost fat metabolism and reduce weight gain in mice at least, according to a Japanese study published in this month's issue of Journal of Nutrition.

Takuya Mori at the Biological Science Laboratories, Kao Corporation, Tochigi and colleagues found mice fed a high fat diet and supplemented with eight-percent fish oil gained less weight and metabolized more fat than others on a diet without fish oil supplemented.

In the study, the obesity-prone mice were fed a diet with 30 percent of the total calories from fat for five months.   One group of mice was supplemented with fish oil while the other was not.

The researchers found in fish oil supplemented mice that higher levels of lipid metabolism related genes which are responsible for enzymes such as carnitine palmitoyltransferase 1a, cytochrome P450 4A10, and malic enzyme.

Additionally, fish oil was found to boost the activity of enzymes related to metabolism.   For instance, enzymes participating in fatty acid beta-oxidation, omega-oxidation and malic had higher activity in the group on fish oil than the controls.

In May, Australian researchers published a study in American Journal of Clinical Nutrition to report that fish oil supplements along with exercise caused reductions in fat mass by about 1.5 kg.

The Australian study involved 75 overweight adults age 25 to 65. The subjects were assigned 260 mg of docosahexaenoic acid (DHA) and 60 mg of eicosapentaenoic acid (EPA) daily.   Both fatty acids are common in fish oil.

The study subjects experienced a 14 percent decrease in blood triacylglycerols and a 10 percent increase in plasma HDL cholesterol compared to the levels at baseline.

Still another study by the University of Georgia researchers showed use of omega-3 fatty acid DHA led to a decrease in the accumulation of fat in the preadipocytes in a dose-dependent manner.   The study appears in the Journal of Nutrition, Vol. 136, pp. 2965-2969.

A scientist affiliated with foodconsuemr.org suggested that omega-3 fatty acids may reduce the adverse impact of saturated and trans-fat, which would otherwise cause adverse effects on cellular physiology.   Studies have showed saturated and trans fat are one of the causes for type-2 diabetes, suggesting that use of omega-3 fatty acids may alleviate the condition.

Source:

Journal of Nutrition, December 2007, Volume 137, 2629-2634

"Dietary Fish Oil Upregulates Intestinal Lipid Metabolism and Reduces Body Weight Gain in C57BL/6J Mice"

Takuya Mori, H. Kondo, T. Hase, I. Tokimitsu, T. Murase