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Vitamin D and respiratory infectious diseases

Vitamin D
and respiratory infectious diseases


Before the Covid 19 epidemic, the scientific community knew that vitamin D supplementation was associated with a significant reduction in respiratory infections. Since the beginning of the pandemic, evidence has emerged that insufficient vitamin D in the blood correlates with an increased risk of developing Covid 19 infection and the severity of symptoms observed. The risk of severe Covid 19 disease is 8 times higher in deficient patients than in non-deficient people


Vitamin D would have 2 actions : An immunomodulating action and an anti-inflammatory action

  • Vitamin D strengthens the immune function against viral diseases. It stimulates the action of immunocompetent cells. It reduces the survival rate of viruses and their ability to replicate.
  • Vitamin D helps to reduce inflammatory phenomena. It thus ensures better control of the cytokine storm demonstrated during the severe phases of the Covid 19 respiratory disease

Usually, the recommended nutritional intake of vitamin D is 200 to 400 IU/d for adults under 65 years of age and 600 IU for those over 65 years of age, for countries in temperate zones. In Norway, a country with reduced sunshine, 800 IU are recommended daily. The American Society of Endocrinology recommends up to 1500 IU per days

Faced with the Covid 19 pandemic, the National Academy of Medicine has been recommending since last May to rapidly measure the level of vitamin D in people over 60 years old suffering from Covid 19, and to administer, in case of deficiency, a loading dose of 50,000 to 100,000 IU, in order to help limit respiratory complications. It also recommends vitamin D supplementation of 800 to 1000 IU/d for people under 60 years of age as soon as the diagnosis of Covid-19 is confirmed.

Vitamin D comes from a variety of sources:

  • the sun, through the action of UVB rays on the skin, is the main source of vitamin D in the body
  • vegetable sources: nuts, seeds, oils, wheat germ, mushrooms (shitaké)
  • animal sources: whole milk, egg yolk, butter, cheese, fatty marine fish (salmon, tuna, herring, sardine).

However, dietary intake of vitamin D provides only 20% of the usual requirements: to reach 200 IU, i.e. half or a third of these requirements depending on the individual, 1 glass of whole milk + 1 yoghurt + 50 g of cheese + 20 g of butter should be consumed daily. Also, it is necessary to reinforce the intake in the usual diet by appropriate supplementation.

As soon as possible, do some physical activity outdoors:

Indeed, being active outdoors leads to a synthesis of vitamin D in the skin thanks to ultra-violet rays.

Otherwise, it is necessary to have a diet rich in vitamin D and to supplement the populations at risk: the elderly, overweight people, people at cardio-respiratory risk, fragile people, tired and stressed subjects.

Cod liver oil is an interesting source of vitamin D and also provides omega 3... It can be used on the advice of a health professional.


Docteur Patrick Aubé, member of the Scientific Council of the Arkopharma Institute



Communiqué of the National Academy of Medicine. 22 May 2020. Vitamin D and Covid-19 - Consult  the PDF.

COVID-19: an increasingly important role for vitamin D. Medscape News, 2020-12-02.

Prevention of Vitamin D deficiency in adults between 18 and 65 years of age. Consult the PDF.