Inclusion Criteria:  Asthma Global Initiative for Asthma (GINA) treatment grade 2-4 (only standard care of inhaled corticosteroid (ICS) and long-acting beta2-agonist (LABA), no additional treatment except as-needed short--acting beta2-agonist (SABA) ACQ-5 score ≥0.75  One (1) of following criteria must be defined:  Increase in forced expiratory volume at one second (FEV1) of >200 mL and >12% post inhaled short-acting β-receptor agonist (SABA) ≥20% decrease in FEV1 after inhalation of Methacholine ≥15% decrease in FEV1 after inhalation of Mannitol ≥10% decrease in FEV1 after exercise Diurnal PEF variability above 15% Eosinophils ≥ 150 µL Speaks fluent Norwegian. For female in fertile age, use of contraception or other indication for non-pregnancy. Signed informed consent and expected cooperation of the participants for the treatment and follow up must be obtained and documented according to ICH GCP, and national/local regulations.  Exclusion Criteria:  Treatment with oral corticosteroid <1 month prior to baseline visit  Treatment with any biological medication, <6 months prior to baseline visit:  Mepolizumab, Reslizumab, Bentralizumab, Dupilumab, and Omalizumab Oral/intravenous antibiotics < 3 months prior to baseline visit Consumption of fish oil (liquid, capsule, powder) as an oral supplement < 1-month prior baseline visit Known fish or shellfish allergy Pregnancy and breast feeding Participant in a confounding study Inflammatory bowel disease (Chron, ulcerative colitis (UC), microscopic colitis), celiac disease, or any chronic disease that possibly affects intestinal absorption and morbidity In case of severe cognitive impairment where the participants are not able to fulfill the study Not willing to participate Any reason why, in the opinion of the investigator, the participant cannot participate.