Krill oil is a supplement that is extracted from various species of antarctic krill (Euphausia superba), which are tiny shrimp-like creatures living within cold ocean waters. In many ways, krill oil is similar to fish oil in that it contains omega-3 fatty acids DHA and EPA. It also contains a flashy antioxidant known as “astaxanthin” which gives it a reddish color.
The astaxanthin helps prevent oxidation and makes krill oil less susceptible to rancidity compared to fish oils. Some have suggested that krill oil is more environmentally sustainable when compared to fish oil due to the fact that all of the krill that is extracted for oil can be renewed within a year. Many consider the combination of “astaxanthin” and its environmental sustainability to be advantageous over fish oil.
Krill Oil Contents
Below is a list of some of the most beneficial contents within krill oil. Those who supplement krill oil often do it for one (or more) of the following: astaxanthin, phospholipid structure, and/or the omega-3 fatty acids (DHA and EPA).
Astaxanthin: This is an antioxidant that has been thought to improve cardiovascular function, immune function, skin health, muscular endurance, and eye function. It has been found to protect against oxidative stress and may be superior antioxidant to other vitamins and supplements. Some researchers consider it a “Super Vitamin” as a result of superior oxidative stress reduction when compared to vitamin E, coenzyme Q10, and various carotenoids.
It is cousin of beta carotene and tends to give krill oil it’s “reddish” color. Krill oil contains adequate astaxanthin to dramatically reduce oxidative stress throughout the body. Some speculate that it may help improve inflammation and prevent neurodegenerative diseases. Research also suggests that it may protect the skin from UV damage and may slow aging in humans.
Phospholipids: These are molecular components that are the foundation for cellular membranes in humans. Since the omega-3 fatty acids in krill oil are linked by a double-chain phospholipid bond, they are thought to have greater bioavailability and are likely efficiently absorbed. Phospholipids are also capable of improving functionality of cellular membranes and protect cells from free radicals.
Phosphatidylcholines (PC): This is a specific class of phospholipids that are found within krill oil. There are several investigational health benefits that may be associated with increased intake of phosphatidylcholines including: preventing cellular aging (possibly neurodegenerative diseases), initiating liver repair, promoting healthy lipid breakdown, and decreasing severity of inflammatory bowel disease (i.e. ulcerative colitis).
Omega-3 fatty acids: Krill oil contains the omega-3 fatty acids DHA and EPA. Each of these fatty acids play important roles in brain development, cognitive function, and regulating mood. In addition to their mental health benefits, both have been associated with optimal physical health as well including reduced risk of inflammation and cardiovascular problems.
Potential Krill Oil Benefits: Mental and Physical
Although there is significant speculation that krill oil may be significantly more potent than fish oil and better absorbed by our bodies, the potential benefits have not been scientifically investigated. Therefore if you take krill oil supplements, you probably don’t definitively know whether they’re effective.
- Absorption: There is evidence that the phospholipid structure of the omega-3 fatty acids within krill is efficiently absorbed by the body. In comparison to other sources of omega-3’s, it is speculated that phospholipid structure leads to the greatest absorption. This means that despite lower doses of EPA and DHA per serving, it may be more efficiently used in comparison to other sources.
- ADHD: It has long been thought that increasing quantities of omega-3 fatty acids, particularly DHA is effective in reducing symptoms of attention-deficit hyperactivity disorder. Most research has been conducted with fish oil, but the primary benefit is derived from the omega-3 fatty acids. Since the absorption is likely better in krill oil, similar effects may be obtained from lower quantities.
- Antioxidant effects: Krill oil contains a potent antioxidant called “astaxanthin” which gives it its reddish color. In addition to scavenging free-radicals, some believe that this antioxidant may help slow the aging process, reduce inflammation, and ultimately prevent early mortality as a result of cardiovascular disease.
- Arthritis: In one study consisting of 90 participants with various forms of arthritis, it was found that krill oil significantly reduced arthritic symptoms within a short-term of just 1 to 2 weeks. Researchers speculate that this is likely due to krill oil’s anti-inflammatory properties.
- Blood sugars: There is some preliminary evidence that krill oil may reduce blood sugar. In a study testing krill’s effect on reducing LDL-cholesterol, it was discovered that 1 to 3 grams per day of krill reduced glucose levels in comparison to a placebo. This suggests that krill oil may be beneficial for those with high blood sugars.
- Cardiovascular disease: In particular, the astaxanthin in krill oil has shown preliminary potential as both an antioxidant and anti-inflammatory agent in rodent models of cardiovascular disease. There have been over 180 human studies demonstrating the safety of astaxanthin with no adverse effects reported. Those who are at risk for cardiovascular disease may benefit from the astaxanthin found in krill oil.
- Cholesterol: Some research also demonstrates krill’s efficacy in reducing LDL-cholesterol, while elevating levels of HDL-cholesterol. Patients that took between 1 and 1.5 grams of krill oil daily over the course of 3 months found that the krill oil was superior to both fish oil and a placebo in the reduction of “bad” cholesterol.
- Cognitive function: Decline in cognition as well as various forms of cognitive impairment tend to result in decreased amounts of omega-3 fatty acids, particularly DHA and EPA within tissues. Supplementation has been shown to drastically improve cognitive function. Since krill provides both these fatty acids, researchers speculate that it may lead to improvements in cognitive function.
- Depression: The EPA and DHA within krill oil may be enough to help curb symptoms of depression. Numerous studies have suggested that these omega-3 fatty acids can help keep depressive symptoms at bay. Although taking fish oil for depression seems to provide more omega-3’s than krill, the omega-3’s within krill may be better absorbed.
- Inflammation: There is evidence that supplementation of krill oil rapidly reduces inflammation. Most research has discovered that individuals taking krill oil notice major reductions in their inflammation within just a couple weeks (14 days).
- Neuroprotection: Since krill contains omega-3 fatty acids (DHA and EPA) in phospholipid structure, and astaxanthin, it is believed that it may function as a neuroprotective agent. Thus preventing cognitive decline and various forms of neuronal dysfunction within the brain.
- Neurodegenerative diseases: Using krill oil as a means to improve cognitive function among those with neurodegenerative diseases has shown some promise. Omega-3 fatty acids have already been documented as improving various aspects of neurodegenerative diseases, and krill oil contains both DHA and EPA.
- PMS: In double-blind trials evaluating krill oil for treating premenstrual syndrome (PMS), it was found that krill oil was superior to fish oil in normalizing blood lipid profiles. In a 2003 study, krill oil was found to reduce “painful periods” as well as emotional symptoms associated with PMS when supplemented for 3 months.
- Triglycerides: Another benefit that krill oil provides is that it reduces levels of triglycerides. Those with high levels of triglycerides are thought to be at greater risk of developing heart disease. One study found that taking between 1 and 3 grams of krill oil per day for several months noticed significant reductions in triglycerides.
Is there sufficient science to support these potential benefits?
Since krill oil is a relatively new trend in the supplement industry, it should not be assumed that taking krill oil will provide significant health benefits until it has been more thoroughly evaluated. Most of the cognitive and mood boosting benefits can be derived specifically from the omega-3 fatty acid content (DHA and EPA). While krill oil does contain omega-3 fatty acids, the amounts of DHA and EPA that it contains is likely suboptimal for targeting any particular mood disorder.
It should also be known that most of the krill oil studies may be biased and/or funded by krill oil companies. Many of the comparison studies utilized “Neptune krill” and compared it to abnormally low amounts of fish oil. It is unknown as to whether these studies were constructed as a marketing ploy to make krill oil appear more efficacious than fish oil’s benefits or a placebo. It is also unknown as to whether other studies with krill remain unpublished as a result of no effect.
Further Krill Oil Research is Warranted
While it can be speculated that krill oil has potential to benefit both physical health and mental health, it is a relatively new “trend” in the supplement industry. There are lot of things to like about krill including: astaxanthin, environmental sustainability, as well as omega-3 fatty acid content. That said, the amount of omega-3 fatty acids may not be substantial enough to provide mental health benefits.
For example, most krill oil supplements contain less than 150 mg of EPA and 90 mg of DHA per serving (which is usually 2 capsules). This would be highly unlikely to alter cognitive function and/or improve mood. Theoretically a person could take a high number of krill oil capsules, but this would be a very inefficient and costly way to improve mental health.
There is also a concern for potential toxicity of extracted krill oil. Krill oil needs to be better tested by independent agencies (e.g. the IFOS) and no significant claims should be made in regards to its ability to improve psychiatric conditions such as depression, anxiety, etc. until more scientific evidence is gathered. While many have made claims that krill oil supplements are beneficial, these claims clearly warrant further scientific investigation.