Krill Oil
A source of omega-3s in phospholipid form offering superior brain bioavailability compared to fish oil triglycerides, plus the bonus of astaxanthin antioxidant.
What is Krill Oil?
Krill oil is a marine-derived supplement extracted from Antarctic krill (Euphausia superba), providing omega-3 fatty acids EPA and DHA bound to phospholipids rather than triglycerides, along with the carotenoid antioxidant astaxanthin.
Known Health Benefits
How It Works
Krill oil delivers EPA and DHA in phospholipid form, primarily phosphatidylcholine. This structural difference is biologically significant because cell membranes are composed of phospholipids, allowing phospholipid-bound omega-3s to integrate more efficiently into membrane structures. Phospholipid-bound DHA crosses the blood-brain barrier via the Mfsd2a transporter, a major facilitatory superfamily domain-containing protein that specifically recognizes lysophosphatidylcholine-DHA. This explains krill oil's superior brain bioavailability compared to triglyceride-bound fish oil DHA. Astaxanthin in krill oil is one of the most potent carotenoid antioxidants, with singlet oxygen quenching activity 550 times greater than vitamin E. It spans the cell membrane bilayer, providing antioxidant protection to both hydrophilic and lipophilic membrane regions. The phospholipid matrix also forms micelles more readily in the aqueous GI environment, improving emulsification and absorption without requiring bile salt co-digestion to the same degree as triglyceride oils. Krill oil's choline content additionally supports hepatic lipid metabolism and neurotransmitter acetylcholine synthesis.
What Research Says
A randomized study by Ulven et al. (Lipids, 2011) demonstrated that krill oil at 62.8% lower EPA+DHA dose achieved equivalent increases in plasma and red blood cell omega-3 levels compared to fish oil, supporting superior bioavailability. Bunea et al. (Alternative Medicine Review, 2004) found krill oil significantly reduced LDL cholesterol, triglycerides, and increased HDL cholesterol compared to placebo in a 12-week RCT of 120 patients. A meta-analysis by Köhler et al. (Nutrition Reviews, 2015) confirmed krill oil's efficacy for reducing cardiovascular risk markers. For inflammation, Deutsch (JACN, 2007) reported that krill oil at 300 mg/day reduced CRP by 30% and significantly improved joint pain scores in arthritis patients within 7–14 days. Ramprasath et al. (Lipids in Health and Disease, 2013) showed krill oil increased the omega-3 index more efficiently than equivalent doses of fish oil triglycerides.
Active Compounds
EPA and DHA (phospholipid form), astaxanthin, phosphatidylcholine
Forms & Bioavailability
Phospholipid-bound omega-3s in krill oil are approximately 68% more bioavailable than triglyceride-form fish oil at equivalent EPA+DHA doses. The phospholipid form also enables absorption even on an empty stomach, unlike fish oil which requires dietary fat.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| General health | 500 mg krill oil/day |
| Cardiovascular support | 1000–2000 mg/day |
| Joint and inflammation | 300–1000 mg/day |
| Cognitive support | 1000 mg/day |
Always consult a healthcare provider for personalized dosing.
Natural Food Sources
- Not available from food; derived from Antarctic krill harvest
Potential Side Effects
Fishy aftertaste (milder than fish oil); GI upset; shellfish allergy risk — do not use
Who Should Avoid It
- Shellfish or crustacean allergy — absolute contraindication
- Active bleeding disorders
- Scheduled surgery within 2 weeks
- Coagulopathies
Pregnancy & Lactation
Limited pregnancy-specific data for krill oil. While the omega-3 content is beneficial during pregnancy, purified fish oil or algal DHA with more established safety data during pregnancy is generally preferred. Consult a healthcare provider before use.
Known Drug Interactions
May enhance blood thinners; interacts with blood pressure medications
Evidence Classification
Supported by cohort studies, case-control studies, or multiple observational studies with consistent findings.
Frequently Asked Questions
Is krill oil better than fish oil?
Krill oil has advantages in bioavailability (phospholipid-bound omega-3s), brain delivery (Mfsd2a transporter), and includes astaxanthin. However, fish oil is more economical for high-dose therapeutic needs. For general health at moderate doses, krill oil may be more efficient per milligram.
Is krill oil sustainable?
Antarctic krill is one of the most abundant biomasses on Earth. Major krill oil brands (Aker BioMarine/Superba) are MSC-certified sustainable and harvest less than 1% of the total krill biomass. The fishery is regulated by CCAMLR international agreements.
Can I take krill oil if I have a shellfish allergy?
No. Krill are crustaceans, and krill oil may contain tropomyosin and other proteins that trigger shellfish allergic reactions. Use algal oil as a safe omega-3 alternative.
Does krill oil cause fishy burps?
Krill oil generally causes fewer fishy burps than fish oil because the phospholipid form creates a more stable emulsion in the stomach. The astaxanthin also provides antioxidant protection against the lipid oxidation that contributes to fishy taste.
How long does krill oil take to work?
Anti-inflammatory and joint benefits have been observed within 7–14 days in clinical trials. Changes to the omega-3 index take 3–4 months of consistent use. Cardiovascular lipid improvements are typically measured after 8–12 weeks.
References
- Evaluation of the effects of Neptune Krill Oil on the clinical course of hyperlipidemia. Bunea R, El Farrah K, Deutsch L. Alternative Medicine Review (2004)
- Metabolic effects of krill oil are essentially similar to those of fish oil. Ulven SM, Kirkhus B, Lamglait A, et al.. Lipids (2011)View study
- Krill oil supplementation increases plasma concentrations of EPA and DHA. Ramprasath VR, Eyal I, Zchut S, Jones PJ. Lipids in Health and Disease (2013)View study
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.