Krill Oil vs Fish Oil in Reducing Cholesterol, Triglycerides

In a head-to-head study between krill oil and fish oil supplementation, krill oil reduced both cholesterol and liver triglyceride levels significantly more than did fish oil in rats. These new findings are in line with a previous study in which both oils were compared in patients who had elevated cholesterol and triglyceride levels.

Krill oil is a rich source of omega-3 fatty acids

Omega-3 fatty acids have demonstrated a number of health benefits, including improved mood, reduced inflammation associated with arthritis, and lower cholesterol and triglyceride levels. Both krill oil and fish oil are excellent sources of omega-3 fatty acids and are taken to address these and other health concerns.

In this latest study, scientists used three groups of rats: one group consumed a control diet, one group had its diet supplemented with 2.5 percent krill oil, and a third group was given 2.5 percent fish oil in its diet. The study lasted six weeks. Within two to three weeks, both krill oil and fish oil significantly inhibited the activity of enzymes that metabolize fat in the liver, although krill oil had a more pronounced effect.

According to the study’s authors, “these data suggest a higher potency of krill oil in decreasing hepatic lipogenesis [production of fat by the liver] when compared to fish oil at relatively short periods of dietary treatment.” Experts do not know why krill oil seems to have this effect, although some suggest the body can better absorb and utilize krill, or that krill may have a different ratio of the two main omega-3 fatty acids.

Those two omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are believed to be responsible for the health benefits associated with krill and fish oils. According to the authors, when krill are made into oil, the product contains 48 times the antioxidant potency of standard fish oils.

Overall, cholesterol declined 33 percent in the krill oil group and 21 percent in the fish oil group; liver triglycerides fell 20 and 10 percent, respectively. The authors noted this study is important because it “elucidated the mechanism behind the beneficial effects of omega-3 supplementation, by demonstrating regulation of lipid synthesizing enzymes.”

Krill are shrimp-like crustaceans that help make up zooplankton and as such are a main food source for whales and many fish and other marine creatures. Harvesting of krill occurs in the Antarctic, where the waters are considered to be less contaminated, and in the seas near Japan.

Beyond claims that krill oil is better than fish oil at lowering cholesterol and triglyceride levels, there is discussion regarding safety. Because krill are lower on the food chain, they are less likely to be contaminated with mercury, PCBs, and other toxins than are fish. Therefore the oils from both forms of marine life could reflect that difference as well.

SOURCES:
Bunea R et al. Alternative Medicine Review 2004 Dec; 9(4): 420-28
Ferramosca A et al. Journal of Animal Physiology and Animal Nutrition doi: 10.1111/j.1439-0396.2011.01135.x/abstract
Ulven SM et al. Lipids 2011 Jan; 46(1): 37-46