In Norway, cod liver oil has been an important dietary source of vitamin D because it contains the biological properties that were critical for the prevention of type 1 diabetes.
A study was conducted to find out whether the intake of dietary cod liver oil or other sources of vitamin D such as supplements taken by either mothers during pregnancy or by children during the first year of their life, was linked to lowering the risk of type 1 diabetes among children.
The nationwide case-control study was done in Norway and consisted of 545 children diagnosed with type 1 diabetes and 1,668 control participants. Families were sent a questionnaire in the mail and were required to answer questions pertaining to the number of times they used cod liver oil or other vitamin D supplements.
Results from the study showed that taking cod liver oil during the first year of life greatly lowered the risk of type 1 diabetes. The consumption of other vitamin D supplements during the first year of life and pregnancy were not connected with type 1 diabetes.
The study concluded that the anti-inflammatory effects of long-chain omega-3 fatty acids found in cod liver oil might have the capability of reducing the risk of type 1 diabetes.
American Journal Clinical Nutrition May 2004;79:820-5