Krill oil is a marine-sourced supplement derived from tiny crustaceans, Euphausia superba, found in the Antarctic Ocean. It is valued for its high content of long-chain polyunsaturated fatty acids (PUFAs), primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Unlike traditional fish oil, the omega-3s in krill oil are naturally bound to phospholipids, a structural feature that influences its stability and absorption. Proper handling and storage practices are necessary to maintain the oil’s quality.
The Direct Answer: Recommended Storage
Refrigeration is generally considered the optimal method for storing krill oil, though it is not always a strict requirement. The best practice is to keep the capsules in a cool, dark environment to preserve their quality. A refrigerator, typically maintaining temperatures between 37 and 40 degrees Fahrenheit (3 to 5 degrees Celsius), provides a consistently cool environment that significantly slows down the natural degradation process.
If refrigeration is not preferred or practical, krill oil should be stored in a cool, dark cupboard away from direct heat sources and light. Krill oil is adapted to cold temperatures and will not tolerate prolonged exposure to heat above approximately 100 degrees Fahrenheit (38 degrees Celsius). Always ensure the container is tightly sealed to minimize exposure to air and humidity, which can otherwise accelerate spoilage.
Understanding Krill Oil Stability
Krill oil’s sensitivity to the environment stems from its unique chemical makeup, particularly its high load of PUFAs. These fatty acids contain multiple double bonds, making them highly susceptible to reaction with oxygen in a process called oxidation or rancidification. Exposure to heat and light acts as a catalyst, speeding up this chemical deterioration.
The structure of krill oil offers a natural defense against this process. The omega-3 fatty acids are primarily attached to phospholipids, rather than triglycerides, which makes them inherently more stable and less prone to oxidation compared to the fatty acids in many fish oils. This phospholipid-bound structure provides a degree of protection, helping to maintain the oil’s integrity over time.
Further enhancing this stability is the presence of astaxanthin, a naturally occurring carotenoid that gives krill oil its characteristic reddish-orange color. Astaxanthin acts as a powerful antioxidant, scavenging free radicals and protecting the delicate PUFAs from oxidative damage. Astaxanthin is an exceptionally potent antioxidant, offering protection thousands of times stronger than other common antioxidants. This compound works sacrificially, meaning it degrades before the omega-3s do, thereby prolonging the oil’s shelf life.
Indicators of Degradation
Rancid oil should be discarded to avoid ingesting potentially harmful by-products of oxidation. The most noticeable sign of spoilage is a strong, unpleasant fishy odor or taste, distinct from the oil’s usual faint marine scent. This intensification of smell indicates that the fatty acids have oxidized, producing volatile compounds like aldehydes and ketones that cause the rancid flavor.
A change in the physical appearance of the capsules is another indicator. While krill oil is naturally reddish-orange and can sometimes appear cloudy at cold temperatures, excessive cloudiness or a marked change in color intensity within the capsule may signal degradation. If the capsules stick together excessively or show signs of leakage, the protective shell may have been compromised, exposing the oil to oxygen and moisture. If any of these signs are present, or if the oil is past its expiration date, dispose of the product.