Salmon diet in patients with active ulcerative colitis reduced the simple clinical colitis activity index and increased the anti-inflammatory fatty acid index – a pilot study

Abstract

Objective. Data concerning the anti-inflammatory effect of dietary n-3 polyunsaturated fatty acids (PUFAs) in patients with ulcerative colitis (UC) are inconsistent. Salmon fillet contains n-3 PUFAs and bioactive peptides that may improve its effects compared to fish oil alone. We assessed the efficacy of a salmon-rich diet in patients with mild ulcerative colitis. Methods. An 8-week intervention pilot study was designed to assess the effects of 600 grams Atlantic salmon consumption weekly in 12 UC patients. Simple clinical colitis activity index (SCCAI), a dietary questionnaire, sigmoidoscopy, selected serum inflammatory markers, fecal calprotectin, and plasma and rectal biopsy fatty acid profiles were assessed before and after intervention. Results. The levels of C20:4n-6 arachidonic acid in biopsies after dietary intervention were correlated with histology and endoscopy scores. The concentrations of n-3 PUFAs, C20:5n-3 eicosapentaenoic acid, C22:6n-3 docosahexaenoic acid, and the n-3/n-6 ratio increased in plasma and rectal biopsies. The anti-inflammatory fatty acid index (AIFAI) increased both in biopsies and plasma accompanied with a significantly reduced SCCAI. Conclusion. Based on evidence of SCCAI and AIFAI and a tendency of decreased levels of CRP and homocysteine, intake of Atlantic salmon may have beneficial effects on disease activity in patients with mild ulcerative colitis.

Key Words::

• Ulcerative colitis
• omega-3 fatty acids
• fish oils
• inflammatory bowel diseases
• diet therapy

Acknowledgments

Special thanks to EWOS Innovation AS for providing the Atlantic salmon consumed by the participants in this study. This work was partly supported by a grant from the Nordic Centre of Excellence Programme in Food, Nutrition, and Health Project (070010) – ‘Mitohealth’ (to R.K.B.). Torbjørn Aarsland at Stavanger Research foundation, Stavanger University Hospital is gratefully acknowledged for his technical assistance. Randi Solheim and Liv Kristine Øysæd at the Section of Clinical Biochemistry, Haukeland University Hospital, are acknowledged for their laboratory assistance. Bjørn Auestad at the University of Stavanger is thanked for valuable statistical advice. Inger Johanne Bø, Wenche Brattebø Fenne, and Hanne Langaune at the Department of Internal Medicine, Stavanger University Hospital are thanked for their efforts during patient recruitment and study visits.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the article.