The Facts on Krill Oil Supplementation

Omega-3 fatty acids appear to have numerous health benefits. Ideally, patients would incorporate foods rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into their daily diets. However, many dislike the foods richest in these nutrients: fish and seafood.

Nutrition-conscious consumers often rely on supplements as an alternative source of omega-3 fatty acids. The large capsule size and aftertaste can make fish oil supplements unpleasant to take, which may explain why krill oil has captured a significant market share in recent years.

Krill oil is a product derived from tiny crustaceans similar to shrimp and is a natural source of EPA and DHA. A recent comprehensive review article compared krill oil with fish oil and examined the available evidence on its efficacy.

According to the author, fish oil is available as capsules and liquid, while krill oil is only available as a capsule. Krill oil capsules contain significantly less EPA/DHA per unit (45 mg to 200 mg) compared with fish oil (300 mg to 2250 mg). Krill oil also contains a bright red carotenoid antioxidant, astaxanthin, though it has unclear clinical benefits.

Krill oil’s fatty acids are incorporated primarily in phospholipids, and limited research has indicated that phospholipids deliver EPA/DHA more efficiently than the triglycerides and ethyl esters found in fish oil. However, studies investigating this hypothesis have reported conflicting results.

Fish oil is less expensive than krill oil, with a standard cost of 1 to 15 cents for fish oil and roughly 30 cents for krill oil per 100 mg of EPA/DHA in OTC products. Krill oil is costly because it must be processed immediately after krill harvest. The author noted that some krill products spoil significantly after they are processed, so EPA/DHA content may be less than the amount labeled.

Studies supporting EPA/DHA for cardiovascular disease prevention were conducted using fish oil. Consumers need a low daily dose of EPA/DHA for cardioprevention (1 gm), which is usually obtained from their diet. Triglyceride reduction requires a higher dose (2 gm to 4 gm), usually attainable only with supplementation. Krill oil cannot be recommended for either indication at this time, as more research is needed.

Pharmacists should encourage patients to increase their fish intake while bearing in mind mercury advisories for specific fish species. If patients cannot or will not eat fish, then recommend fish oil supplements. Pharmacists should also help patients understand how much fish oil they need, and to read labels to ensure the products they select have the appropriate EPA/DHA content.