Daily supplements of krill oil were associated beneficial effects on the endocannabinoid system, which consists of a group of neuromodulatory lipids and receptors that influence appetite, pain sensation, mood and memory, according to results published in Nutrition & Metabolism.
In addition, only krill oil, and not menhaden (fish) oil or olive oil, was associated with significant reductions in levels of 2-arachidonoylglycerol (2-AG) in obese subjects. 2-AG is an endocannabinoid reported to be increased in obese people.
“The novel finding of the present study is that krill oil, more efficiently than menhaden oil, was able to reduce endocannabinoid levels in the plasma despite the fact that the effects of the two dietary treatments on EPA and DHA plasma concentrations were comparable and even slightly lower in the krill oil group than in the menhaden oil group,” wrote the researchers, led by Sebastiano Banni from the University of Cagliari.
“One possible explanation for the different effects of krill oil and fish oil might be […] the more efficient incorporation of n-3 long chain polyunsaturated fatty acids (LCPUFA) into visceral adipose tissue phospholipids, and subsequent decrease in arachidonic acid incorporation associated with krill oil supplementation, hence leading to impaired endocannabinoid biosynthesis,” they added.
The study was welcomed by Nils Hoem, PhD, chief scientist at Aker BioMarine, who noted it confirmed previous findings from a 2009 study with obese rats (Journal of Nutrition, Vol. 139, pp. 1495-1501)
“Helping normalize endocannabanoid levels in obese subjects may help address potential long-term health issues, including metabolic syndrome, though these are preliminary findings and additional research is necessary to draw solid conclusions,” said Hoem.
“However, it is important to note that the study suggests that phospholipid form of omega-3 fatty acids found in krill oil was responsible for the beneficial effects observed in this study,” he added.
Krill are tiny shrimp gaining attention as a rich source of omega-3, as well as other nutrients.
There are about 85 species of the deepwater marine planktonic crustacean, or deepwater shrimp, which are the planet's most abundant animal biomass and which when captured and converted to oil, pack 48 times the antioxidant punch of standard fish oils, according to ORAC antioxidant scales.
The researchers – a team of scientists from Finland, Norway, Italy and USA, including krill player Aker Biomarine – recruited 63 overweight and obese subjects aged between 35 and 64, and randomly assigned them to receive two grams per day of either krill oil (Superba krill oil, Aker BioMarine), menhaden oil (Omega-Pure), or olive oil for four weeks.
The krill oil provided 309 mg per day of EPA/DHA 2:1, whereas the menhaden oil provided 390 mg per day of EPA/DHA 1:1.
Results showed that only obese people receiving the krill oil displayed significant reduction in 2-AG levels: No significant decreases were observed following menhaden oil or olive oil, and no decrease was observed in overweight people receiving the krill oil.
“These data show for the first time in humans that relatively low doses of LCPUFA n-3 as krill oil can significantly decrease plasma 2-AG levels in obese subjects in relation to decrease of plasma phospholipid n-6/n-3 LCPUFA ratio,” wrote the authors.
“Future studies will have to investigate whether longer dietary interventions and higher dietary levels of krill oil, apart from still down-regulating the endocannabinoid system, also improve the metabolic syndrome, thus possibly representing an alternative to [the cannabinoid CB1 receptor] antagonists/inverse agonists for the treatment of this disorder,” they concluded.
Source: Nutrition & Metabolism
2011, 8:7, available online here: http://www.nutritionandmetabolism.com/content/8/1/7
“Krill oil significantly decreases 2-arachidonoylglycerol plasma levels in obese subjects”
Authors: S. Banni, G. Carta, E. Murru, L. Cordeddu, E. Giordano, A.R. Sirigu, K. Berge, H. Vik, K.C. Maki, V. Di Marzo, M. Griinari