Krill oil is derived from Euphausia superba, a species of tiny, shrimp-like crustaceans harvested primarily from the cold waters of the Antarctic. This marine oil is studied as a nutritional supplement due to its distinct composition of beneficial fats and antioxidants. Dry Eye Syndrome (DES) is a common, chronic condition characterized by inadequate tear film quality or quantity, leading to discomfort and visual disturbance. Since the underlying cause of chronic DES is often a cycle of inflammation, researchers are investigating whether krill oil can help manage these persistent symptoms by targeting this inflammation.
Scientific Evidence for Dry Eye Relief
Clinical research provides measurable evidence that krill oil supplementation can effectively reduce the symptoms and signs of dry eye disease. A randomized, double-masked, placebo-controlled trial found that participants taking krill oil experienced a statistically significant improvement in symptoms after three months of use. This improvement was tracked using the Ocular Surface Disease Index (OSDI), a validated tool that measures the impact of DES on a patient’s vision-related function and quality of life.
The study noted that the krill oil group saw an average reduction of 18.6 points in their OSDI score, a greater change than the placebo group. Both krill oil and standard fish oil supplements led to a reduction in tear osmolarity, which is a measure of tear film salt concentration and a key indicator of DES severity. The krill oil group also showed a significant decrease in the basal tear levels of the pro-inflammatory cytokine Interleukin 17A (IL-17A), demonstrating an anti-inflammatory effect directly on the eye’s surface.
Clinical signs of DES, such as ocular bulbar redness and tear breakup time, also showed improvement with krill oil supplementation. Tear breakup time measures how long the tear film remains stable on the eye’s surface before evaporating; an increase suggests a healthier, more protective tear film. These specific improvements in both subjective symptoms and objective inflammatory markers are promising for krill oil as a dietary aid for managing DES.
Key Components and Anti-Inflammatory Action
Krill oil’s effectiveness against dry eye stems from its unique combination of active ingredients that target inflammation and oxidative stress. The primary beneficial components are the long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Chronic inflammation is a central factor in the progression of DES, and EPA and DHA are precursors to specialized pro-resolving mediators, which are compounds that actively work to resolve and shorten inflammatory reactions.
These omega-3s incorporate into cell membranes, including those of the lacrimal glands, helping to modulate the body’s overall inflammatory response and the specific inflammation on the ocular surface. By reducing this inflammation, EPA and DHA help improve the function of the meibomian glands, which produce the oily layer of the tear film. Better meibomian gland function results in a more stable tear film that resists evaporation, directly addressing a primary cause of DES.
Krill oil naturally contains astaxanthin, a powerful carotenoid that gives the oil its deep red color and acts as a potent antioxidant. Astaxanthin provides protection against oxidative stress, which can damage the delicate tissues of the eye from environmental factors or prolonged screen exposure. This antioxidant activity helps shield the ocular surface and tear glands from free radical damage, supporting overall eye health.
Krill Oil Versus Standard Fish Oil
A key difference between krill oil and most standard fish oils lies in the chemical structure of the omega-3 fatty acids they contain. In krill oil, the EPA and DHA are predominantly bound to phospholipids, which are the same compounds that form the structure of human cell membranes. Conversely, the omega-3s in most conventional fish oil supplements are bound to triglycerides.
This phospholipid structure in krill oil is believed to enhance the bioavailability of the omega-3s. The phospholipid form facilitates easier absorption and transportation across cell membranes, potentially allowing the EPA and DHA to be delivered more efficiently to the target tissues, including the eyes. This difference in absorption may explain why, in clinical studies, krill oil has sometimes shown a greater impact on subjective dry eye symptoms compared to fish oil, despite similar total omega-3 doses.
Krill oil’s natural inclusion of astaxanthin is another structural advantage, as this component is typically absent in fish oil supplements unless added during manufacturing. This naturally occurring antioxidant works in synergy with the omega-3s, providing a dual-action benefit of reducing both inflammation and oxidative stress.
Safe Dosing and Potential Side Effects
While there is no single universally established dose, effective krill oil dosing for dry eye relief often mirrors the amounts used in successful clinical trials. One study that demonstrated significant improvement in OSDI scores utilized a daily dose providing 945 mg of EPA and 510 mg of DHA. Consumers should look for supplements that provide a similar total amount of long-chain omega-3 fatty acids, which may require taking two or more capsules depending on the product concentration.
Krill oil is generally well-tolerated, but some individuals may experience mild gastrointestinal side effects. These can include stomach upset, bloating, or a fishy aftertaste, though the phospholipid form is often associated with less of the latter compared to triglyceride-based oils.
There are important safety considerations to discuss with a healthcare provider before starting krill oil supplementation.
Safety Considerations
Krill oil can slow the process of blood clotting, which may increase the risk of bleeding, especially when taken alongside anticoagulant or antiplatelet medications.
Individuals with a known allergy to shellfish should avoid krill oil, as it is derived from a marine crustacean.
It is standard medical advice to discontinue krill oil use at least two weeks before any scheduled surgical procedure.