This fall, Oslo University Hospital will launch a research project to find out whether cod liver oil has beneficial effects against COVID-19. Cod liver oil is indeed rich in vitamin D and omega-3 fatty acids, which would make it an ally in strengthening the immune system and even limiting the severity of a respiratory infection such as that caused by SARS- CoV-2.

Vitamin D plays an essential role in the absorption of certain minerals by the body. Its origin is double because it is provided by food and synthesized by the body in the skin under the action of solar or ultraviolet rays. In the first case, the foods richest in vitamin D are cod liver oil and fatty fish such as herring, pilchard, mackerel, sardines, anchovies, trout, perch, salmon ... Many studies have looked into the value of this vitamin in the context of the coronavirus epidemic: vitamin D would indeed be a valuable ally against acute respiratory infections of viral origin.

Thus, Great Britain recently decided to distribute vitamin D supplementation to 2 million elderly and vulnerable people during the winter, while Spanish researchers affirmed that nearly 80% of patients affected by Covid-19 presented vitamin D deficiencies. Last May, the Academy of Medicine also mentioned its interest because it could play a role in the regulation of the cytokine inflammatory response at the origin of the acute respiratory distress syndrome which characterizes the severe forms of Covid -19. "A significant correlation between low serum vitamin D levels and mortality from Covid-19 has been shown," she said.

 Supplementation or life hygiene: what is the most protective factor?

However, "vitamin D cannot be considered as a preventive or curative treatment for SARS-CoV-2 infection, but could be considered as an adjunct to any form of therapy by reducing the inflammatory storm", concluded the organization. It is this avenue that will be explored by doctors at the University Hospital of Oslo, focusing on one of the foods richest in vitamin D: cod liver oil. Doctors want to answer this question: does cod liver oil provide a real protective effect or is it because people who consume it generally have a healthy lifestyle, which limits the risk of infection. ?

“This issue will now be investigated further in what will be one of the largest clinical studies ever conducted in Norway,” the doctors say in a backgrounder. “Cod liver oil is rich in vitamin D and omega-3 fatty acids and the study will be based on the results of the large COVID-19 study called“ Koronastudie ”which was launched this spring. Preliminary data from this still-ongoing "Koronastudie" study showed that consumers of cod liver oil may have a reduced risk of contamination for COVID-19 infection and a lower risk of becoming seriously ill in the event of a disease. 'infection.

"Valuable information on how to prevent infection"

A first discovery which is not without confirming the conclusions of previous scientific work evoking the beneficial properties of omega-3 fatty acids and vitamin D on respiratory tract infections and COVID-19. "However, the results of the study cannot rule out that users of cod liver oil exhibit other protective characteristics in their lifestyle," say the researchers. This is why they believe that another so-called "randomized" study (randomly distributing a placebo or the drug substance tested) is necessary to find out whether cod liver oil itself really offers protection against COVID. -19.

This Norwegian study will include at least 70,000 participants, making it one of the largest clinical studies ever conducted in this country. During this, half of the participants will take a daily dose of cod liver oil, while the other half will receive a placebo product. The participants, who will not know in which group they will be placed, are being recruited. "The results can give us valuable information on how we can prevent infection with COVID-19 and other viral illnesses such as seasonal flu and the common cold," explains Prof. Arne Søraas, first author, in the document. of the study.

The study will end in April 2021, but the researchers do not say when their results will be publicly available. In the meantime, a sufficient supply of vitamin D is already essential on a daily basis, especially during periods of confinement, because in addition to strengthening the immune system, it plays an essential role in the quality of bone and muscle tissue. In April, ANSES * drew up a list of foods rich in vitamin D to remove from storage or add to your basket during future shopping. It also recalled the importance of ensuring an adequate food intake for people at risk: the elderly and dark or dark skinned and postmenopausal women.