Krill oil

Krill oil is made from a species of krill [Euphausia superba]. Two of the most important nutrients in krill oil are: (1) omega-3 fatty acids similar to those of fish oil and (2) phospholipid-derived fatty acids (PLFA), mainly phosphatidylcholine (alternatively referred to as marine lecithin). Also, antioxidant experimental egg products with krill oil likely contained astaxanthin, a natural antioxidant. The fatty acid composition in the phospholipids in krill oil has been described in two papers.

Several studies have shown toxic residues in Antarctic krill and fish.

Krill species
Krill are small crustaceans that can be found in all the world’s oceans, but mostly in the Northern (Arctic) and Southern (Antarctic) polar seas. They belong to the same animal family as shrimp, lobsters and crabs. There are more than 80 different known krill species. Among these, the Antarctic krill, called Euphausia superba, is the kind of krill that can be fished, because it lives in large swarms and swims in open water. Krill swim in huge swarms that can be as long as six kilometers in length and have a density of up to one million individuals per cubic meter.

Krill oil vs. fish oil
The majority of omega-3 fatty acids are either bound to phospholipids or triglycerides. While triglycerides consist of three fatty acids bound to a glycerol backbone, phospholipids only have two fatty acids which are bound to a phosphorus group that is further linked to a headgroup. The headgroup can consist of choline, ethanolamine, glycerol, inositol or serine. Triglycerides are highly hydrophobic (they do not mix with water). Phospholipids are amphipathic because they contain a headgroup on one end that is hydrophilic and a hydrophobic chain on the other end. Due to this dual structure, phospholipids are able to mix with water. Phospholipids are also used to build membranes that make up the cell wall of every single cell in the human body. By creating a double layer interspersed with proteins that keeps the cell’s content inside and foreign elements outside of the cell, phospholipids function as cellular ‘gate-keepers’ and are absolutely essential for proper functioning of all cell membranes.

Several human intervention studies investigated if the molecular form (phospholipid versus triglyceride) of omega-3 fatty acids is of importance for EPA and DHA levels detected in blood plasma.

In a randomized, double-blind, parallel clinical trial 76 overweight and obese men and women received either krill oil, fish oil, or olive oil for one month. The daily amount of EPA was similar in the krill oil and fish oil group, but the DHA quantity was approximately half as much in the krill oil group compared to the fish oil group. Nevertheless, after 4 weeks of supplementation the researchers found that the plasma EPA concentrations were higher in the krill oil group compared to the fish oil group, and the average DHA concentrations were similar to the fish oil group. Krill oil supplementation resulted in increased plasma EPA levels and revealed equal increases in DHA, but at half the dose in comparison to fish oil.

In another study, 113 subjects with normal or slightly increased total blood cholesterol and/or triglyceride levels were randomized into three groups and given krill oil, fish oil, or a placebo for 7 weeks. The results from the krill oil group suggested a 45 % higher total EPA and DHA plasma level than in the fish oil group after seven weeks of administration.

Ecological concerns
The harvesting of Antarctic krill is relatively new. The vast majority is harvested for feed for fish farms. A small percentage (2 percent in the 2009-2010 season) is harvested for human consumption.

Krill is considered by many scientists to be the largest biomass in the world. Antarctic krill is fundamental to the survival of almost every species of animal that lives in the Antarctic or sub-Antarctic waters and island groups. Because Antarctic krill are so important, in 1982, the United States, the United Kingdom, Australia, South Africa, New Zealand, Chile, European Community, Germany and Japan formed a treaty organization to ensure that krill were being harvested sustainably. Named the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR-pronounced "camel-lahr"), it now manages the fin fish (mostly toothfish) and krill fisheries in the Southern Ocean. Scientists from some of the CCAMLR member nations, including Australia, the United States and the United Kingdom, conduct research in the Southern Ocean and make recommendations to CCAMLR that enable the organization to make management decisions. Currently there are 25 Members of CCAMLR, 24 member states and the European Community.

CCAMLR has successfully implemented a precautionary and ecosystem approach in managing the krill fishery. The krill fishery is considered by some of those scientists to be among the best managed fisheries in the world, providing strict catch limits on licensed vessels, and scientific observers on board. CCAMLR scientists are working to take into account the possible effects of climate change on the ecosystem as well as effects of changes in technology and operational pattern of krill fishing vessels on the fishery when making management decisions.