The study – recently published in the Scandinavian Journal of Gastroenterology – reports that rats fed a diet supplemented with 5% krill oil were significantly protected from important markers of induced experimental colitis – including reduction of the colon shortening, and had improved markers of protein oxidation.
The research team, including MD Tore Grimstad of the Stavanger University Hospital and the University of Bergen, Norway , said the krill oil – supplied by Aker Biomarine – protected the rats from the markers of dextran sulfate sodium (DSS)-induced colitis, indicating an anti-inflammatory and protein antioxidant effect of krill oil.
Kjetil Berge, R&D Director of Aker BioMarine Antarctic said the study results demonstrate the potential anti-oxidant and anti-inflammatory benefits of krill, adding that the results from “open up new possibilities for krill oil for digestive health, and may provide a basis for future studies in humans."
Speaking with NutraIngredients, Dr Grimstad – the first author of the study – cautioned that whilst the results of his study showed promise, several of the study’s secondary findings were not statistically significant.
“It’s tempting to say that it’s a wonderful study. And most variables are going in the right direction, but the fact is that not everything is statistically significant – and we have to say that,” he said.
Krill for colitis
Grimstad explained that the goal of the study was to investigate whether krill oil had a beneficial effect on a model of experimental colitis.
He cited previous research studies testing omega-3 from fish oil – that have shown promising, but varied results in the past – as a basis to test krill oil. He said that although, like fish oil, krill oil is made up of omega-3 fatty acids, the chemical make-up of the omega-3 is different.
“Krill oil is different, it has a different chemical structure, as most of the omega-3 fatty acids are bound to phospholipids instead of triglycerides. Theoretically that could be beneficial when it comes to absorbtion, and makes it an interesting substance to investigate,” said Grimstad.
The researcher added that krill oil has other key differences from fish oils, including the presence of certain antioxidants which may prove to be beneficial.
Study details
In the four week experiment, Grimstad and his colleagues split 30 rats into three equal groups; with one group fed a standard diet (negative control), another group fed a standard diet but with DSS induced colitis brought on in the final week (DSS), and a final group fed a standard diet plus 5% krill oil with DSS induced colitis brought on in the final week (DSS + Krill).
The team found that in rats fed krill oil and later induced with colitis, the colon length was not shortened, and also found markers of protein oxidation were significantly reduced following the krill oil supplementation.
“Most of the markers for inflammation were [also] changed towards a favourable direction, however they did not reach statistical significance,” said Grimstad.
“Although we cannot say the markers changed from a statistical point of view, it is interesting because most parameters were shifted in a beneficial direction,” he added.
The researcher said that one of the limitations of the study was the small sample size, which with 10 rats per group, lacked statistical power. A larger pool of data, he suggested, would help to reveal whether the shifts in disease index scores were chance or significant.
Human potential?
Grimstad cautioned that he “can’t say for sure” how the results of the study – on rats induced with colitis – could be translated into humans, but did note that previous research in omega-3 fish oil, which had shown great promise in animal models has now been found to have variable results in human studies.
He claimed that there was an “obvious need” to for further research:
“In further animal studies it would be interesting to compare krill oil directly to fish oil, and of course the next step is human studies to see if we can achieve results,” he said.
Source: Scandinavian Journal of Gastroenterology
Published online ahead of print, doi: 10.3109/00365521.2011.63402
“Dietary supplementation of krill oil attenuates inflammation and oxidative stress in experimental ulcerative colitis in rats”
Authors: T. Grimstad, B. Bjorndal, D. Cacabelos, O.G. Aasprong, E.A.M Janssen et al