Vitamin D, a renewed image

By Aurélie SIFFRE, French Doctor of Pharmacy.

Vitamin D and health crisis

Before the health crisis, vitamin D was mainly given to infants after they left the maternity hospital, to children up to five years of age on a paediatrician’s prescription, and to elderly people, mostly women after the menopause. Spontaneous demand at the counter was then confidential, except for a few followers of cod liver oil capsules, nostalgic for the remedies of our grandparents.

However, when the French National Academy of Medicine’s press release of 22 May 2020 [1], which was widely echoed by the media, mentioned the value of vitamin D as a complement to other therapies for SARS-CoV-2 infection, this announcement caused supply tensions in pharmacies for vial and oral drop forms in the following weeks. Fortunately, the laboratories reacted very quickly, offering a wide choice of vitamin D, in tablets to be swallowed, chewed, in drops, in powder, in drinkable spray, of natural or synthetic origin, alone or in association with other star elements recommended against Covid (Zinc, vitamin C, etc.) …

Indeed, vitamin D contributes to normal absorption of calcium and phosphorus, which is linked to the maintenance of normal bones, muscle function and teeth; but also, to the normal function of the immune system, in particular by stimulating macrophages and dendritic cells [1]. Under the effect of the sun’s ultraviolet rays, this prohormone called cholecalciferol or vitamin D3 is synthesised in the dermis and then activated by the liver (calcidiol) and the kidney (calcitriol) to become effective.

The demand for vitamin D

Demand is as high in the sunnier regions as it is in the northern ones and concerns the whole range of the population: men, women, children, and all ages. Around the equator, between latitudes 42^oN and 42^oS, a regular and moderate exposure of 30 minutes on the face and arms covers all the daily needs of the body in vitamin D. Outside these latitudes, and especially in winter, it is estimated that daily exposure alone does not meet the body’s vitamin D requirements [4]. It is therefore recommended to ensure this through diet with fatty fish such as salmon, mackerel, sardines, but also egg yolks, offal and cheese, or to take an oral supplement.

VITAMIN D, PHARMACIST’S ADVICE

Vitamin D3 in food supplement form can be of animal (lanolin) or plant (often extracted from seaweed) origin, making it suitable for a vegan diet. Patients have plenty to choose from!

The population nutrient reference (PNR) is 15 micrograms per day for adults [2].

[1]  French National Academy of Medicine’s press release of 22 May 2020
[2] ANSES, vitamin D
[3] OpinionWay for Synadiet
[4] FAO, vitamin D
[5] Journal of the Academy of Nutrition and Dietetics