The question: I've been hearing a lot about krill oil supplements. Is it superior to fish oil?
The answer: Unlike fish oil supplements made from fatty fish like salmon and sardines, krill oil is made from tiny shrimp-like crustaceans. Both provide EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the two omega-3 fatty acids found in fish. The concentration of omega-3 fatty acids, however, is usually lower in krill oil than fish oil.
Manufacturers say the body can absorb the omega-3 fats in krill oil more readily than those in fish oil. That's because a large portion of the DHA and EPA in krill oil is bound to phospholipids. The physical properties of phospholipids allow them to dissolve in water, allowing them to be easily absorbed.
The omega-3s in fish oil, on the other hand, are attached to triglycerides, which don't readily dissolve in water. The fact that krill oil contains readily absorbed phospholipids suggests that a smaller dose of omega-3's from krill oil may be equally as effective as a higher concentration found in fish oil.
There's some evidence to support this notion. A study published in 2011 demonstrated that three grams of krill oil (providing 543 mg EPA + DHA) and 1.8 grams of fish oil (864 mg EPA + DHA) raised blood levels of omega-3 fatty acids to the same degree.
Krill oil is also said to contain a higher concentration of astaxanthin, an antioxidant that comes from the algae krill feed on. (Astaxanthin gives krill and other crustaceans like shrimp and lobster their reddish-pink colour.) One report suggests this antioxidant helps lower blood fats and raise HDL (good) cholesterol.
Is krill oil better than fish oil? Does it outperform fish oil when it comes to beneficial effects in the body? It's far too soon to know the answer. There's very little research on the use of omega-3 fatty acids from krill oil. The vast majority of studies have used fish oil supplements.
One study conducted in 120 people with high blood cholesterol found that taking two to three grams of krill oil – versus three grams of fish oil – was more effective at lowering LDL (bad) cholesterol. Both doses, however, significantly raised HDL cholesterol.
Two preliminary studies suggest that krill oil might help reduce the symptoms of premenstrual syndrome and rheumatoid arthritis. However, both studies have been criticized for design flaws.
Bottom line: if you want to supplement your diet with EPA and DHA, there's far more research backing fish oil. I'm not saying krill oil isn't worth taking as a means of boosting your omega-3 intake. It's just too soon to know if it has the numerous benefits attributed to omega-3's from fish oil.
Leslie Beck, a registered dietitian, is the national director of nutrition at BodyScience Medical. She can be seen every Thursday at noon on CTV News Channel'sDirect (www.lesliebeck.com).
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