What is Krill Oil?
Krill are shrimp-like crustaceans that are approximately 1 to 6 centimeters long. They live is the ocean, where they feed mainly on phytoplankton. They're near the bottom of the food chain and are eaten by whales, seals, penguins, squid and fish.
Commercial fishing of krill occurs primarily in the Southern Ocean and the northern Pacific Ocean along the coasts of Canada and Japan. Krill that are caught are used for aquaculture and aquarium feeds, sport fishing bait or they are eaten as food. In Japan, krill that's caught for food is called okiami.
Krill oil, the oil that's found naturally in krill, is extracted and sold as a nutritional supplement. It's sold in some health food stores and online in capsule form.
Krill oil contains omega-3 fatty acids, which is the main reason it's becoming popular as a nutritional supplement.
Another reason krill oil is becoming popular is because it contains an antioxidant called astaxanthin. The algae that krill eat produces the bright red pigment astaxanthin that gives krill and other crustaceans such as lobster and shrimp their reddish-pink color.
Antioxidants protect our body cells from damage from free radicals, unstable substances that are thought to contribute to certain chronic diseases. Unlike many other antioxidants, astaxanthin crosses the blood-brain barrier, where it could theoretically protect the eye, brain and central nervous system from free radical damage.
The recent popularity of krill oil supplements has raised concerns that it could threaten the population of its predators, including penguins, seals and whales.
Why Do People Use Krill Oil
People use krill oil for the same reasons they use fish oil, flax oil or other omega-3 fatty acids. Unlike fish oil, krill oil doesn't cause fishy burps or an aftertaste, a common side effect of fish oil. Also, krill oil contains higher amounts of astaxanthin than fish oil. Here are some specific conditions for which it's used.
1) High Cholesterol
Krill oil is being studied as a natural remedy for high cholesterol. In one study, 120 people were given krill oil, fish oil or a placebo. Krill oil reduced LDL (commonly referred to as "bad") cholesterol by 34% and increased HDL ("good") cholesterol by 43.5% compared to the placebo. In comparison, fish oil reduced LDL cholesterol by 4.6% and increased HDL cholesterol by 4.2%. Krill also lowered triglycerides.
2) Premenstrual Syndrome
Preliminary research suggests krill oil may help reduce symptoms of premenstrual syndrome (PMS), however, more research is needed.
A study in the Journal of the American College of Nutrition examined krill oil (300 mg daily) compared to a placebo and found that krill oil was effective at reducing arthritis symptoms and inflammation.
People with allergies to seafood shouldn't use krill oil. People with bleeding disorders shouldn't use krill oil unless under the supervision of a qualified health professional.
Side effects of krill oil may include loose stools, diarrhea or indigestion.
Possible Drug Interactions
People taking blood thinners (anticoagulant or anti-platelet medication), such as aspirin, warfarin (Coumadin), heparin, clopidogrel (Plavix), non-steroidal anti-inflammatory medications (NSAIDS) such as ibuprofen (Motrin, Advil), naproxen (Naprosyn, Aleve) should only use krill oil under a physician's supervision.
Krill oil should also be used with caution by people taking herbs and supplements that are thought to increase the risk of bleeding, such as ginkgo biloba and garlic.
Bunea R, El Farrah K, Deutsch L.Evaluation of the effects of Neptune Krill Oil on the clinical course of hyperlipidemia. Altern Med Rev. (2004) 9.4: 420-428.
Deutsch L. Evaluation of the effect of Neptune Krill Oil on chronic inflammation and arthritic symptoms. J Am Coll Nutr. (2007) 26.1: 39-48.