If I protect myself from the sun, am I at risk of a vitamin D deficiency? Here’s how much and how to get some sun
The team of doctors and fact-checking experts from the National Medical Association addresses the main health concerns
Key points
For some years now, there has been a growing awareness of the harmful effects of the sun, with the result that people are taking far greater precautions than in the last century, when the myth of the tan was fuelled by aesthetic ideals – which, fortunately, are now a thing of the past – that associated a tan with high socio-economic status. Those most health-conscious – who diligently apply sun cream, cover up and seek out the shade – are, however, bombarded with contradictory messages: on the one hand, recommendations aimed at reducing the risk of skin cancer; on the other, the suspicion that doing so might deprive us of the benefits of sun exposure, foremost among which is an adequate level of vitamin D.
But how much vitamin D do we need?
This concern is well-founded, because 80–90 per cent of the body’s required vitamin D intake comes from the skin, which produces it when exposed to ultraviolet B (UVB) rays. These same UVB rays, which cause sunburn, are blocked by all the filters contained in sun creams and lotions, as well as by the special fabrics used in protective clothing labelled with the abbreviation UPF (Ultraviolet Protection Factor).
However, only a minimal amount of these rays is needed to produce the amount of vitamin D required by an adult. Most experts therefore believe that, even when protecting oneself from the sun, we receive more than enough radiation in our daily lives at our latitudes. In any case, when there is a risk of developing a genuine deficiency – or this is confirmed by a 1,25-dihydroxyvitamin D blood test – the solution is never to expose oneself recklessly to the sun – as the disadvantages would outweigh the benefits – but, if necessary, to take supplements, as is recommended for children, pregnant women, the elderly, and those who are bedridden or in care homes.
What do you need to do to make sure you don’t run out?
An adult with no chronic illnesses, who leads a reasonably healthy lifestyle, synthesises more than enough vitamin D through their skin, supplemented at least in part by the vitamin D obtained from foods that are naturally rich in it – such as oily fish (salmon, mackerel, herring, tuna), egg yolks, butter and cheese – or which have been fortified during processing, such as milk or breakfast cereals.
As far as sun exposure is concerned, there are no precise figures on the duration and conditions required to ensure sufficient exposure to produce the vitamin D one needs, but it is generally believed that, in our latitudes, 10–20 minutes outdoors during the middle of the day – not even every day – with your face and hands uncovered, is sufficient. Even a sun cream with SPF 50, such as those usually recommended, blocks 98 per cent of UVB rays. This is sufficient to protect the skin, but it is thought to allow enough radiation through to trigger the production of the vitamin D necessary for the body’s wellbeing.
