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Open Access Highly Accessed Research article

Supplementation of diet with krill oil protects against experimental rheumatoid arthritis

Michelle Ierna1, Alison Kerr1, Hannah Scales1, Kjetil Berge2* and Mikko Griinari3

Author Affiliations

1 MD Biosciences Gmbh Postfach, Gewerbestrasse 9, 8132 Egg b. Zürich, Switzerland

2 Aker BioMarine ASA, Fjordallèen 16, P.O Box 1423 Vika, NO-0115 Oslo, Norway

3 Clanet ltd, Kultarinnantie 1b, 02660 Espoo, Finland

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BMC Musculoskeletal Disorders 2010, 11:136  doi:10.1186/1471-2474-11-136

Published: 29 June 2010



Although the efficacy of standard fish oil has been the subject of research in arthritis, the effect of krill oil in this disease has yet to be investigated. The objective of the present study was to evaluate a standardised preparation of krill oil and fish oil in an animal model for arthritis.


Collagen-induced arthritis susceptible DBA/1 mice were provided ad libitum access to a control diet or diets supplemented with either krill oil or fish oil throughout the study. There were 14 mice in each of the 3 treatment groups. The level of EPA + DHA was 0.44 g/100 g in the krill oil diet and 0.47 g/100 g in the fish oil diet. Severity of arthritis was determined using a clinical scoring system. Arthritis joints were analysed by histopathology and graded. Serum samples were obtained at the end of the study and the levels of IL-1α, IL-1β, IL-7, IL-10, IL-12p70, IL-13, IL-15, IL-17 and TGF-β were determined by a Luminex™ assay system.


Consumption of krill oil and supplemented diet significantly reduced the arthritis scores and hind paw swelling when compared to a control diet not supplemented with EPA and DHA. However, the arthritis score during the late phase of the study was only significantly reduced after krill oil administration. Furthermore, mice fed the krill oil diet demonstrated lower infiltration of inflammatory cells into the joint and synovial layer hyperplasia, when compared to control. Inclusion of fish oil and krill oil in the diets led to a significant reduction in hyperplasia and total histology score. Krill oil did not modulate the levels of serum cytokines whereas consumption of fish oil increased the levels of IL-1α and IL-13.


The study suggests that krill oil may be a useful intervention strategy against the clinical and histopathological signs of inflammatory arthritis.