The numerous health benefits of omega-3 fatty acids may make you wonder if you should start taking a supplement. Omega-3s are essential for your brain, nervous system and vision to function properly. A moderate body of research supports taking omega-3s for cardiovascular health, particularly to reduce low-density lipoprotein or LDL cholesterol and triglyceride levels. Fish oil and krill oil supplements are two omega-3 supplement options. Understanding a few small differences between the two can help you make an educated purchase.
Nutrients in Krill and Fish Oil
Krill oil and fish oil both contain two important omega-3s -- DHA, or docosahexaenoic acid, and EPA, or eicosapentaenoic acid. If you have heart disease, talk to your doctor about starting a fish oil supplement. Omegas-3 have been shown to lower triglyceride levels and decrease the risk for blood clots. Because of this effect on clotting, also called platelet aggregation, use caution if you take Coumadin or asiprin, which have similar effects. DHA and EPA have also been studied for positive effects on depression, menstrual pain and rheumatoid arthritis. More studies are needed to validate these associations.
Omega-3s are present in similar concentrations in krill and fish oil supplements. Check the label for doses -- the concentration depends on the brand you choose. A typical recommendation is to take 1 to 2 grams of an omega-3 supplement per day, regardless of the source. Talk to your doctor or pharmacist to determine a safe dosage for you.
Availability and Absorption
In 2011, "Lipids in Health and Disease" published a study evaluating the bioavailability of nutrients from krill oil and fish oil supplements. Bioavailability refers to how well your body can actually absorb and use the nutrients listed on the label. The researchers found that omega-3s from krill oil were better absorbed. Analysis of the supplements showed that krill oil contained a percentage of EPA and DHA in their "free form" while fish oil did not. This was attributed to superior bioavailability. More and larger studies are needed to confirm whether the EPA and DHA in krill oil supplements are easier for the body to absorb.
Krill Astaxanthin
One compound in krill supplements is astaxanthin, which is a carotenoid derived from the orange-red shell of krill. Astaxanthin is a strong antioxidant that reduces cellular damage associated with aging and environmental toxins. Although astaxanthin appears to have benefits, researchers have not yet determined if the amount in typical krill oil supplements is sufficient to provide benefit. Nonetheless, the combination of omega-3s and astaxanthin makes krill oil an appealing option to consider.
Options
Most people stand to benefit from increasing their intake of omega-3s. If you are allergic to shellfish, you should not take krill oil supplements. Vegetarian sources of omega-3s are also available. These are usually produced from seaweed. Whichever source you choose, pay attention to dosages and look for cold-pressed oils. Cold pressing tends to retain the beneficial properties better during processing.
References
- "Lipids in Health and Disease"; Incorporation of EPA and DHA Into Plasma Phospholipids in Response to Different Omega-3 Fatty Acid Formulations - A Comparative Bioavailability Study of Fish Oil vs. Krill Oil; J.P. Schuchardt et al.; August 2011
- University of Maryland Medical Center: Docosahexaenoic Acid (DHA)
- "Comparative Biochemistry and Physiology"; Fatty Acids of Astaxanthin Esters in Krill Determined by Mild Mass Spectrometry; S. Takaichi et al.; October 2003
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