Melanoma skin cancer is the fifth most common form of cancer in the UK, and according to Cancer Research UK, 86 per cent of the 16,000 new cases every year are preventable. However, sunshine also has proven benefits to our health. Could our reliance on sunscreen be denying us these?
Our bodies need sunlight to help us create vitamin D. While some is absorbed from food, most of it is produced via a chemical reaction in our skin that relies on the energy from ultraviolet (UV) rays. The amount of vitamin D you have governs how much calcium your body absorbs. Not enough vitamin D can lead to diseases like rickets and osteomalacia, where bones are left soft, weak and warped.
Unfortunately, the UVB rays that help our bodies create vitamin D also cause sunburn, skin ageing and skin cancer. So, using sun cream daily throughout the summer months – assuming it’s applied correctly and regularly – could theoretically block the body’s best access to vitamin D.
What’s more, some dermatologists believe that just as important as vitamin D, if not more so, is nitric oxide. Also created in the body after exposure to UV light, nitric oxide causes blood vessels to relax and expand, lowering blood pressure. Dr Richard Weller, a dermatologist who studies the effect of sunlight on blood pressure at the University of Edinburgh, said of his research in 2013: “We suspect that the benefits to heart health of sunlight will outweigh the risk of skin cancer.” Weller also appeared on the BBC’s Trust Me, I’m A Doctor in 2016, suggesting that there’s no reason to avoid sunlight, just don’t get burnt.
Further doubt over sun cream arose with a study published in the Journal Of The American Medical Association in May. The Maryland-based team found that active ingredients in four types of sun cream found their way into the bloodstream after one day of use. While this sounds scary, it’s not known whether sunscreen ingredients such as oxybenzone and octocryolene have any effect in the body.
Even if they do, that doesn’t necessarily mean that the average person would be affected: the participants in the experiments followed the maximum guidelines of their sun creams for four days, applying four times a day. On the other hand, a study from King’s College London in 2018 found that, in everyday use, people usually apply less than half the recommended amount of sun cream. The Maryland researchers suggest that you don’t throw out your sun cream until we have a better idea about its effects.
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Whether or not sun cream comes with risks, the danger of sunlight is well proven. “There is overwhelming evidence that skin damage, even from mild tans, accumulates over the years,” writes Dr Monty Lyman in his book The Remarkable Life Of The Skin. “Even though melanin is the original sunscreen, a suntan is not a sensible form of sun protection: it provides a sun protection factor [SPF] of around only 3 and leaves a trail of DNA destruction in its wake.”
Does this mean we should avoid the sunshine entirely? “The fact that humans have evolved melanin shows that sunlight isn’t wholly good,” explains Lyman in an email. “But also the fact that humans have evolved to have less melanin the further they have moved away from the equator shows it has some benefits! Essentially, there are benefits and risks with sunlight, and a balance needs to be struck.”
The optimal amount of time spent in the sunshine to get enough vitamin D depends on your skin tone, says Lyman. As a rule of thumb, between March and September, half the time it takes for your skin to burn, two or three times a week, is enough unprotected time to get all the vitamin D you need. He adds that we should spend time outside every day for personal wellbeing, and there is no need to actively seek the sunshine to ‘top up’ vitamin D.
This is especially true when holidaying somewhere hot: a recent study published in the British Journal Of Dermatology showed that using high-SPF sun creams doesn’t prevent vitamin D production when sunlight is strong. While there might be much more to learn about the risks of sun cream, there isn’t the evidence to suggest we should ditch it yet.