Krill Oil

Medically reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD — GMJ Editorial Board

What is Krill Oil?

Krill oil is a marine-sourced supplement extracted from Antarctic krill (Euphausia superba), small shrimp-like crustaceans that form the foundation of the ocean’s food chain. This omega-3 fatty acid supplement contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in phospholipid form, primarily phosphatidylcholine, along with the antioxidant astaxanthin that gives krill oil its characteristic red color.

Unlike traditional fish oil where omega-3s are bound to triglycerides, krill oil’s phospholipid structure may enhance absorption and bioavailability. Krill are harvested sustainably from Antarctic waters under strict environmental regulations to protect marine ecosystems.

Health benefits & uses

Strong evidence:
• Cardiovascular health: Multiple studies demonstrate krill oil’s ability to reduce triglycerides, increase HDL cholesterol, and improve overall lipid profiles comparable to fish oil supplementation.

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Moderate evidence:
• Inflammatory markers: Research shows krill oil may reduce C-reactive protein and other inflammatory biomarkers more effectively than fish oil, potentially due to its astaxanthin content and phospholipid delivery system.
• Joint health: Limited clinical trials suggest improvements in joint pain and stiffness, particularly in individuals with mild osteoarthritis symptoms.

Limited evidence:
• Cognitive function: Preliminary studies indicate potential benefits for memory and cognitive performance, though more research is needed.
• Premenstrual syndrome: Small-scale studies suggest possible reduction in PMS symptoms, but evidence remains insufficient for definitive recommendations.
• Skin health: Early research explores potential benefits for skin hydration and elasticity, attributed to astaxanthin’s antioxidant properties.

How it works

Krill oil provides omega-3 fatty acids EPA and DHA in phospholipid form, which may be more readily absorbed than the triglyceride form found in fish oil. These omega-3s incorporate into cell membranes, influencing membrane fluidity and cellular signaling pathways.

EPA primarily supports cardiovascular health by reducing inflammation and improving blood vessel function, while DHA is crucial for brain and eye health. The phospholipid carrier, particularly phosphatidylcholine, supports liver function and may enhance omega-3 bioavailability.

Astaxanthin acts as a potent antioxidant, protecting the omega-3 fatty acids from oxidation and providing additional anti-inflammatory benefits. This combination may explain why some studies show enhanced effectiveness compared to traditional fish oil supplements.

Dosage

Typical adult dosages range from 500mg to 3000mg daily, usually taken with meals to optimize absorption. Most clinical studies use doses between 1000-2000mg daily. There is no established Recommended Dietary Allowance (RDA) or Upper Limit (UL) specifically for krill oil.

The American Heart Association recommends 250-500mg combined EPA and DHA daily for cardiovascular health. Since krill oil contains approximately 120-150mg of combined EPA and DHA per 1000mg, dosing should account for this concentration.

Healthcare providers may recommend higher doses for specific therapeutic purposes. Starting with lower doses and gradually increasing can help minimize potential digestive side effects.

Food sources

Krill oil is exclusively available as a dietary supplement, as krill are not consumed directly as food in most cultures. The omega-3 fatty acids found in krill oil can be obtained from other marine sources including:

• Fatty fish (salmon, mackerel, sardines, anchovies)
• Fish oil supplements
• Algae-based omega-3 supplements (suitable for vegetarians)
• Seafood (oysters, mussels, crab)

However, the specific phospholipid-bound omega-3s and astaxanthin combination found in krill oil is unique to this supplement form.

Safety & side effects

Krill oil is generally well-tolerated by most adults. Common mild side effects may include:

• Fishy aftertaste or burping
• Mild digestive upset
• Nausea when taken on an empty stomach
• Loose stools at higher doses

Serious adverse effects are rare when used as directed. The astaxanthin content may cause a harmless reddish tint to skin with very high doses, though this is uncommon with typical supplementation.

Quality varies among manufacturers, so choosing products with third-party testing for purity and potency is recommended.

Interactions

Drug interactions:
• Anticoagulant medications: May enhance effects of warfarin, heparin, and other blood-thinning drugs, potentially increasing bleeding risk
• Antiplatelet drugs: Could amplify effects of aspirin and clopidogrel

Supplement interactions:
• Other omega-3 supplements: Combined use may increase total omega-3 intake beyond intended levels
• Vitamin E: May work synergistically as antioxidants but could theoretically enhance anticoagulant effects

Individuals taking blood-thinning medications should consult healthcare providers before starting krill oil supplementation.

Who should be cautious

• Shellfish allergies: Individuals with crustacean allergies should avoid krill oil due to potential allergic reactions
• Bleeding disorders: Those with hemophilia or other clotting disorders should use only under medical supervision
• Scheduled surgery: Discontinue 2 weeks before elective procedures due to potential bleeding risk
• Pregnancy and breastfeeding: Safety data is limited; consult healthcare providers before use
• Children: Dosing and safety not well-established in pediatric populations

Frequently asked questions

Is krill oil better than fish oil?

Some studies suggest krill oil may be more bioavailable due to its phospholipid structure, but both provide beneficial omega-3 fatty acids. The choice often depends on individual tolerance, cost considerations, and specific health goals.

Can vegetarians take krill oil?

No, krill oil is an animal-derived product. Vegetarians should consider algae-based omega-3 supplements that provide EPA and DHA from plant sources.

How long does it take to see benefits?

Blood lipid improvements may be observed within 2-4 weeks, while anti-inflammatory effects may take 6-12 weeks. Individual responses vary based on baseline health status and dosage.

Does krill oil need to be refrigerated?

While not always required, refrigeration can help maintain potency and reduce oxidation, especially after opening. Follow manufacturer storage recommendations.

Can I take krill oil with other medications?

Generally safe with most medications, but consult your healthcare provider, particularly if taking blood thinners or preparing for surgery.