Norway decided to test this hypothesis and initiate research on the beneficial effects of cod liver oil against Covid-19.A wide-ranging studyOslo University Hospital is looking for nearly 70,000 volunteers to take part in a huge clinical study on cod liver oil and the coronavirus.In this country of 5.5 million inhabitants, this is a very important research effort and one of the largest clinical studies ever carried out in Norway, one of the main producers of this precious oil whose health benefits have been recognised for decades.This new study is the result of a previous one, the Koronastudie, carried out last March. After asking 150,000 people to answer a detailed questionnaire about their habits, the researchers found that regular consumers of cod liver oil are less often infected with the coronavirus.An oil rich in vitamin DCould this miracle oil then be used preventively? ‘The difference is not astronomical, but significant enough for us to take a closer look,’ explains Arne Soraas, a doctor and researcher at the Department of Microbiology at Oslo University Hospital.And this result did not really surprise the researchers! Cod liver oil is very rich in vitamin D, the importance of which has already recognised in the prevention of respiratory tract infections. In fact, ‘at least one in five Norwegians eat it every day,’ explains Arne Soraas. This could explain why Norway is one of the three European countries least affected by the coronavirus.It's probably still a little early to say, but vitamin D deficiency is one of the avenues being explored by researchers around the world to understand certain predispositions to develop serious forms of the disease.Several hospitals around the world have given vitamin D to sick people and, combined with other treatments, this seems to have been beneficial. The results of the study are eagerly awaited.