Dietary intake of the long-chain omega-3 polyunsaturated fatty acids, EPA and DHA, has been associated 'with many health benefits - from cardiovascular health and improved cognitive function to reduced levels of inflammation. Although various organizations have established recommended daily intakes for EPA and DHA, the typical 'western diet is known to fall short of these, requiring dietary supplementation to make up the shortfall.
One novel source of phospholipid omega-3 PUFAs is krill oil extracted from Euphausia superba, an Antarctic krill species. Krill has a shrimp-like appearance with big black eyes and a reddish, semi-transparent shell. They live in huge swarms in the cold Antarctic waters of the Southern Ocean, feeding on microscopic marine algae rich in enzymes that can produce omega-3 fatty acids, which are then accumulated in the krill themselves and can subsequently be extracted in krill oil. Moreover, algae are capable of synthesizing the powerful antioxidant astaxanthin, which is taken up by krill and protects PUFAs from oxidation - it is also the reason for the characteristic deep red colour of krill oil.
Most importantly, the majority of the EPA and DHA in krill oil is bound to a particular type of fat - phospholipids - unlike other marine oils, which confine them to different chemical forms of fat, usually either triglycerides or ethyl esters. The differences are quite significant, particularly in the area of utilization by the body: dietary triglycerides and phospholipids differ in their physiological functions in the body; triglycerides are primarily used either as energy or as energy storage in fat tissues. When delivered in triglyceride form, a portion of the beneficial omega-3s are burned as energy or stored in the body's fat reserves - as a result the dosage of triglyceride omega-3 oils must be large enough to compensate for that loss and ensure that sufficient omega-3s are available on a cellular level.
Recent human clinical studies have shown that phospholipid omega-3s may be a more desirable form. When compared with triglyceride omega-3s, a smaller amount of the phospholipid kind is required to achieve equal bioavailability in the body's cells and organs, which results in krill oil capsules being smaller than their fish oil counterparts. There's more good news that consumers will love: krill oil is dispersible in the stomach fluids, eradicating the repeating that fish oil capsules so commonly incur.
Studies have demonstrated that increased blood levels of ERA and DHA are accompanied by health benefits in humans, placing great importance on the bioavailability of these omega-3 fatty acids in the blood. The term 'bioavailability' refers to how much of a substance reaches the blood and describes absorption and survival rate of said substance in the body. Two recent human intervention studies investigated whether the molecular form (phospholipid versus triglyceride) of omega-3 fatty acids is important for the bioavailability of ERA and DHA in blood plasma. The study, performed by Kevin C. Maki and his co-workers at the Provident Clinical Research and Meridien Research Centres, USA, was conducted as a randomized, double-blind, parallel arm trial. Within this setup, 76 overweight and obese men and women were randomly distributed into three groups to take Superba Krill oil, fish oil, or olive oil for 4 weeks. To avoid any influence, the supplementation given was unknown to both the study subjects and researchers. Whereas the received daily amount of EPA was similar in the krill and fish oil groups, the DHA quantity was approximately half as much in the krill oil group as that in the fish oil group. Nevertheless, at the end of the study period, plasma analysis showed that the mean ERA concentrations were higher in the krill oil than the fish oil group and the mean DHA concentrations were similar in both groups. Both sources of omega-3 fatty acids were safe, generally well-tolerated and significantly increased ERA and DHA levels in plasma compared with the control group. Most importantly krill oil supplementation (2 g/day) resulted in increased plasma ERA bioavailability and, in the case of DHA, equal bioavailability but at half the dosage of fish oil. Overall, after dose adjustment, the total increase of EPA and DHA in the plasma of subjects who received Superba Krill oil for 4 weeks was 24% higher than that of the subjects who received fish oil (Figure 1).
The second study, performed by researchers at Akershus University College and University of Oslo, investigated whether a lower dose of ERA and DHA provided in phospholipids, compared with omega-3 fatty acids provided in triglycerides, shows equal bioavailability of these fatty acids in plasma. In this study, 113 subjects with normal or slightly increased total blood cholesterol and/or triglyceride levels were randomized into three groups and given Superba Krill oil, fish oil or placebo for 7 weeks. The daily supplementation of total EPA and DHA was approximately 37% less in the krill oil group than in the fish oil group. Results showed that dietary omega-3 administration led to a similar increase of plasma omega-3 fatty acids in both the krill and fish oil groups compared with the control group. These findings suggest that a lower dosage of EPA and DHA in phospholipid form is required to obtain comparable plasma EPA and DHA levels to the triglyceride form of omega-3 supplementation. After adjustment of EPA and DHA levels to the daily dose given, the results from the krill oil group suggest a total EPA and DHA plasma level that was 45% higher than in the fish oil group after 7 weeks of administration. Moreover, the subjects with the highest baseline values of triglycerides further benefited from krill oil supplementation and showed decreased plasma triglyceride levels. Additionally, the HDL-cholesterol/triglyceride ratio, a risk predictor for heart disease, was significantly decreased after Superba Krill oil, but not fish oil, treatment.
These two human clinical studies demonstrate that intake of Superba Krill oil is more potent than fish oil in increasing total plasma EPA and DHA values and suggest that there is a higher bioavailability of omega-3 fatty acids bound to phospholipids than in the triglyceride bound omega-3s found in fish oil.
In the first study mentioned, in which 2 g of Superba Krill oil was administered for 4 weeks, the blood levels of endocannabinoids were also measured. The results confirmed data in the literature describing increased levels of endocannabinoids in overweight and obese persons with respect to normalweight subjects. Superba Krill oil - but not menhaden oil or olive oil - was able to significantly decrease 2-AG in obese subjects, which correlated with a decreased plasma phospholipid omega-6/omega-3 ratio. These data show for the first time that relatively low doses of omega-3 fatty acids such as Superba Krill oil can significantly decrease plasma 2-AG levels in obese human subjects and reveal that it presents a promising approach for counteracting elevated EC levels. By changing the balance between omega-6 and omega-3 fatty acids and reducing EC precursor availabilities, Superba Krill oil may provide therapeutic benefits such as lowered triglyceride blood levels and decreased fat deposition in and around organs. It could also alleviate metabolic dysfunctions such as dyslipidemia, visceral adiposity and the associated inflammatory states that play a role in atherogenesis and the subsequent increased cardiovascular risk.
Krill are an underexploited biomass - one that is more than double the size of that of all humans. Aker BioMarine has made a commitment to sustainability and maintaining the highest standards in all aspects of the krill fishing operations. The company conforms to all CCAMLR requirements and has taken sustainability and environmental responsibility even further by addressing all the issues on CCAM LR's wish list of best practices, co-operating with WWF-Norway in conservation efforts and obtaining MSC certification for the sustainability and full traceability of Aker BioMarine's krill products, from sea to shelf. Although krill's health benefits have been explored in several studies, many of the potential areas of its health-promoting effects are as yet unknown. In addition, various interesting data have been obtained in preclinical studies that are yet to be confirmed in human trials; of particular interest will be the areas of joints, brain health and pet food. Krill oil supplements provide an excellent source of EPA and DHA - phospholipid omega-3s - and, owing to its increased bioefficiency, improved compliance and eminent sustainability, is arguably superior to others available.
[Author Affiliation]
For more information
Henrik Traaholt
Business Director and Brand Manager, Europe
Aker BioMarine
Tel. +44 241 300 00
henrik.traaholt@akerbiomarine.com
www.akerbiomarine.com
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