A study shows that a vitamin D deficiency can increase the risk of severe form of coronavirus, or even death. The Academy of Medicine recommends its dosage in certain populations. What are the signs of a deficiency? Which foods to favor? What daily advice for refueling?
[Mis à jour le dimanche 24 mai 2020 12h43] Vitamin D is essential for the proper functioning of our body. Even more so in the midst of a coronavirus epidemic during which immune defenses are in high demand. But what role does it play and should you supplement yourself to protect yourself from this virus?
A preliminary study published on medrxiv shows that people vitamin D deficient have a 15% additional risk of developing severe form of Covid-19 disease and twice the risk of death than people who are not deficient. Vitamin D may reduce COVID-19 severity by authors, authors say. removing the cytokine storm (responsible for the inflammatory process) in COVID-19 patients.
What the Academy of Medicine thinks : in a press release of May 23, 2020, the Academy of Medicine confirms that this vitamin modulates the functioning of the immune system by stimulation of macrophages and dendritic cells and “plays a role in regulating and suppressing the cytokine inflammatory response that causes acute respiratory distress syndrome that characterizes the severe and often lethal forms of Covid-19”. However “Vitamin D cannot be considered as a preventive or curative treatment for SARS-CoV-2 infection”. She recommends:
- of quickly measure serum vitamin D levels (i.e. 25 OHD) in people over the age of 60 with Covid-19, and administer a loading dose of 50,000 to 100,000 IU in the event of a deficiency which may contribute to limit respiratory complications.
- ofprovide vitamin D supplementation 800 to 1000 IU / day in people under the age of 60 upon confirmation of the diagnosis of Covid-19.
The National Agency for Food, Environmental and Occupational Health Safety (ANSES) recalled last April in a press release the importance of an adequate intake of vitamin D, in the absence of sun, particularly for the elderly, people with dark or even dark skin and menopausal women. She recommends expose to the sun at least 15 minutes a day to cover his daily needs.
“Vitamin D plays an essential role in bone structure; it helps fight demineralization and osteoporosis”, explains Dr Yves Fouré, general practitioner. Indeed, vitamin D is involved in the functioning of bone metabolism. It promotes intestinal absorption of calcium and phosphorus. By its action, it participates in bone consolidation, good mineralization of teeth and muscle building. Vitamin D3 (cholecalciferol) is the main form of vitamin D in humans: it represents 80 to 90% of vitamin D intake (to which it is often assimilated). The other form of vitamin D is vitamin D2 (ergocalciferol).
The blood dosage of vitamin D has long been prescribed to check the proper absorption of calcium by the body, especially in people with bone and dental problems, and in the elderly. “But today, this dosage is recognized as useless by epidemiological studies. In fact, the vast majority of the population is deficient in vitamin D, so this dosage does not teach much “says Dr. Fouré. In fact, the High Authority for Health produced a report in 2013 in which it stressed that the usefulness of this dosage has not been demonstrated, in most cases.
HAS still recommends the dosage in these cases:
- follow-up after a kidney transplant,
- follow-up after obesity surgery in adults
- follow-up in the elderly prone to falls.
- the dosage can also support the diagnosis of rickets or bone decalcification, in order to better determine the cause of these pathologies, or to verify the effectiveness of certain treatments, in particular against osteoporosis.
The sun remains the main source of vitamin D
A blood vitamin D concentration of less than 20 nanograms per mL of blood is considered to be insufficient. Deficiency is defined by a vitamin D levels below 12 nanograms per mL of blood. Vitamin D deficiency can lead to
- A bone loss (linked to an abnormality in the development of the bone) and an increase in its brittleness causing rickets and fractures. This decrease in bone mass promotes the risk of fracture. This risk is particularly high when physical activity is reduced or nonexistent.
- Of muscle pain and weakness can cause falls in the elderly.
- Vitamin D deficiency can also lead to tiredness.
Vitamin D deficiency is very common in mainland France, especially at the end of winter and at the beginning of spring. According to the National Nutrition Health Study (2012), 80% of French people are affected. Several studies have shown that French women over 50 are the Europeans most deficient in vitamin D. Severe deficits are more rare (around 5%) and affect the elderly more often. “It should supplement all women from the age of 50, and everyone from the age of 75. This is all the more necessary for bedridden people, in Ehpad for example “, adds Dr. Fouré.
According to ANSES, the risk of vitamin D deficiency is higher in some people:
- seniors
- people with dark or dark skin, for whom the synthesis of vitamin D via sun exposure is less effective,
- postmenopausal women, whose hormonal disruption can lead to bone demineralization, which increases the risk of fracture.
With the sun, food is the other source of vitamin D intake. It is found in large quantities in cod liver oil, for example, “but it would be necessary to absorb liters and liters to have a satisfactory contribution. The sun remains the richest source”, points out our interlocutor.
The foods richest in vitamin D are:
- Oily fish such as herring, sardines, salmon or mackerel
- Organ meats, especially liver
- The egg yolk
- Dairy products, especially those enriched with vitamin D
- Butter and margarine
- Cheese
- Meat.
ANSES reminds us that it is important to vary and balance our diet throughout the year and to regularly consume these foods to cover our daily vitamin D requirements. The good benchmark: eat two servings of fish per week, including one serving of oily fish. Ideally prefer fresh fish, but if this is not possible, bet on canned sardines, herring, mackerel in the natural way.
An overdose can have harmful consequences for the heart and kidneys.
The recommended dose is one ampoule of 100,000 units every two months, during periods of low sunlight (or 600 to 800 units per day). “Paradoxically, an overdose of vitamin D can lead to weakening of the bones”, says Yves Fouré. This is called hypervitaminosis. “The use of food supplements containing vitamin D can expose to too high intakes, which can cause hypercalcemia – high level of calcium in the blood circulation – leading to the calcification of certain tissues, and thus have cardiological and renal consequences“, completes ANSES on its website in its article of April 17, 2020. In any case, the use of food supplements must be done on a dietary or medical indication.
The sun and its ultraviolet rays are the main source of vitamin D. “Vitamin D is synthesized by the skin under the action of the sun; but beware, prolonged exposure to UV increases the risk of skin cancer”, warns Dr. Fouré.
• In spring, 15 to 20 minutes of sun exposure of the hands, forearms and face ensures the daily intake of vitamin D.
Thank you to Dr Yves Fouré, general practitioner. Sources: “News, Containment: Ensure sufficient vitamin D intake through food “, Anses, published on April 17, 2020.
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