When it comes to sun protection, two arguments have been getting a lot of air time. First, that we should be slapping on SPF (sun protection factor) every day – even in winter – lest we end up looking haggard. Second, wearing SPF even on days when there’s very little sun puts us at risk of vitamin D deficiency. Which is right?
Neither, says Prof Helen MacDonald of the University of Aberdeen, an expert in sunlight and health. “SPF only stops UVB [radiation],” she says, explaining that although this wavelength both increases the risk of burning and skin cancer and is used by our bodies to produce vitamin D, it doesn’t cause the skin damage that leads to signs of ageing – that’s longer-wavelength UVA radiation. In order to block UVA, you need a broad spectrum sunscreen, one with a four- or five-star UVA rating. A moisturiser that just says “SPF 30” and nothing else on the packet is unlikely to work.
