A precautionary case for making damn sure we are not Vitamin D deficient, in the era of coronavirus

By Rupert Read.

This article was first published on Medium.

This note concerns how we should think precautionarily about Vitamin D as a possible way to help prevent the coronavirus.

With the UK being now, scandalously, the European country most affected by the coronavirus outbreak, it’s natural for people to want to help boost their immune systems; but how important is vitamin D in the fight against coronavirus?

Known as the sunshine vitamin, vitamin D is an essential nutrient that regulates the intake of calcium, magnesium and phosphorous, while also supporting a naturally effective immune system.

Evidence is accumulating that there is a significant link between low levels of the vitamin and higher mortality rates — although most agree it is too early to categorically say one way or the other and more work is needed. One piece of this evidence was very suggestive data from Italy showing extreme Vitamin D deficiency in most of those in a set of Covid-19 post-mortems.

In the absence of decisive evidence, there is nevertheless a cast-iron precautionary case for ensuring that one is not Vitamin D deficient. That means it’s time to get out in the Sun! It would be a mistake to think that safety from Covid lies inside your house if you hide away from getting Vitamin D as a result. So sunbathe a bit, open that window, get on the balcony, go into your garden, walk in the park. Don’t hide away behind sunblock. (I’m obviously not saying ‘Get skin cancer’! I’m saying while avoiding sunburn, do get some exposure to the Sun to get some Vitamin D in your system.)

An area of particular interest is the disproportionate number of UK deaths within ethnic minority groups, with links starting to be drawn between vitamin D deficiency and infection rates in the black, Asian and minority ethnic (BAME) communities. The amount of vitamin D produced by the body from sunlight depends on the time of day, where you live and the colour of your skin.

Deficiency is prevalent in people with darker skin, especially in higher latitudes, due to a natural barrier towards the UVB rays needed to penetrate the skin. This natural barrier comes in the form of melanin.

Melanin is the term used for a group of natural pigments that affect how light or dark your skin colour is, the more melanin you have, the darker your skin colour. This melanin competes with vitamin D in the skin for UVB absorption, meaning that darker skin types allow less UVB to enter the skin and consequently produce less vitamin D.

Public Health England wisely updated its guidance during the lockdown, urging everyone to consider taking a daily vitamin D supplement for the duration of the ‘stay home’ period. But the best way to get Vitamin D whenever possible is the natural way: there is no substitute for sunlight.

A hypothesis: the unexplained excess BAME deaths (even once one has controlled for social class etc) in the UK and other relatively high-latitude countries, from Covid-19, may be due at least in part to Vitamin D deficiency. If this hypothesis is correct, then as we move into summer the disproportionately high number of BAME deaths from Covid may start to ease. (This eventuality, if it comes, would tend to confirm the hypothesis.)

But obviously there is a real worry here for everyone, and especially BAME people, as we move into the autumn and (especially) winter. In the UK, for part of the year, it is essentially impossible to get Vitamin D from sunlight, when the Sun is too low. This period is longer for those with more melanin in their skins.

Conclusion: A vital part of public health preparations for a possible big second wave of the coronavirus this autumn will centre around Vitamin D. On both an individual and a societal basis, a key precaution against the coronavirus appears likely to be ensuring we get sufficient Vitamin D, one way or another.