The Difference Between Fish Oil & Krill Oil

In 2009, Americans spent $739 million on fish oil and krill oil supplements, spurred by claims they can help prevent and treat a variety of conditions including heart disease, cancer, depression and arthritis. Both types of supplements provide similar nutrition and are backed by scientific studies touting their benefits, so it's not always easy to see how they differ or which one to choose. Cost could be a deciding factor, however, since krill oil is the more expensive of the two.

Fish Oil

The first recorded commercial production of fish oil began in 1775 in England, with cod liver oil. Today, fish oil supplements are also extracted from other oily cold-water fish including halibut, herring, mackerel, salmon, tuna or the blubber from seals or whales. Fish oil supplements frequently contain small amounts of vitamin E to prevent spoilage and may have other added vitamins.

Krill Oil

Krill are small crustaceans similar to shrimp found throughout the world's oceans. Krill feed on antioxidant-rich phytoplankton and microalgae, and in turn are a dietary staple for whales, small fish and seabirds. Although the Japanese have been consuming krill for decades, commercial krill oil was first introduced to the market in 2003.

Nutritional Content

Both fish oil and kill oil contain the omega-3 fats known as eicosapentanoic acid, or EPA, and docosahexanoic acid, or DHA. Omega-3 fats are antioxidants, substances that may protect your cells from the harmful effects of free radicals. Natural fish oil contains about 30 percent EPA and DHA, while krill oil typically has 14 percent EPA and DHA. While this makes it appear that fish oil has higher levels of antioxidants, krill oil also contains vitamins A and D and astaxanthin, an extremely potent antioxidant. In fact, krill oil is 48 times more potent than fish oil, according to Michael R. Eades, M.D, founder of Medi-Stat Medical Clinics in Arkansas.

Benefits

Although there have been more than 8,000 scientific studies of fish oil, there have only been a handful of studies looking at krill oil as of early 2011. In summarizing the fish oil research, the National Institutes of Health concluded that fish oil supplements are helpful in treating and preventing high triglyceride levels that are associated with heart disease and untreated diabetes, and for helping to prevent heart disease and heart attacks. The early studies on krill oil have found it may have the ability to reduce menstrual symptoms, decrease lipid and blood glucose levels and fight inflammation.

Digestion

The EPA and DHA acids in krill and fish oil are found in different chemical configurations. In fish oil, the acids are in triglyceride form, meaning they have to go through an extra step before being absorbed into the walls of cells. With krill oil, they're in a phospholipid form that is more easily absorbed by your body. Because krill oil is absorbed differently, it isn't as likely to cause the same fishy burping and aftertaste people experience using fish oil supplements. Although there hasn't been a direct link between krill and an allergy to shrimp, avoid taking krill oil if you have a shrimp allergy.