Biosea cod liver oil with omega-3 orange flavoured is a nutrient-dense oil made from the livers of several species of the cod fish.it contains large amounts of vitamins a, d, and omega-3 fatty acids, and has been used for centuries to promote immune system health and prevent rickets. rickets is a bone condition in children caused by lack of vitamin d. the powerful nutrient-dense composition of cod liver oil also is thought to reduce inflammation, promote brain function, improve eyesight, and boost the immune system.