Cod-liver oil used to be a widely used daily dietary supplement for children in the Nordic countries during the dark part of the year.
Daily dose is about 5 ml.
The content of vitamin C in cod-liver oil is in the area of 250 µg. pr. 100. A spoonful of ordinary cod-liver oil contains about 30 µg. of vitamin D.
The product can contain added vitamin E to protect the unsaturated fatty acids.
Cod-liver oil is also available with added zinc and vaseline for external use.