Trust me, wearing sunscreen all year round really DOES cause more harm than good, says PROFESSOR TIM SPECTOR

As social media spats go, it was all rather unexpected – and unseemly – for a group of prominent medics.

At the centre of the storm was top health scientist Professor Tim Spector and his brief comments on a new study which suggested, in lab mice at least, Vitamin D deficiency could increase the risk of cancer returning. 

Prof Spector, a genetic epidemiologist at King's College London and the founder of the ZOE nutrition app, wrote on X, formerly Twitter, that the study was 'another reason to stop using SPF 50 all year round, which blocks our natural defences'.

His point was, he believed, simple and uncontroversial. Sunlight triggers the production of Vitamin D in our bodies, and wearing sunscreen, particularly a strong one like SPF 50 throughout the year – especially in winter, when damaging ultraviolet (UV) rays are less strong – may affect the amount of the crucial compound we are able to generate.

Healthy Vitamin D levels have been linked with staving off dementia, heart and metabolic health, better survival from breast cancer, lowering blood pressure and improving sleep and mood. This appeared to be another piece of evidence that making sure we had adequate amounts was a good idea.

Top health scientist Professor Tim Spector was at the centre of a social media storm following his suggestion to stop using SPF 50 all year round as it blocks our 'natural defences'

But Prof Spector's words ignited a furore. His post, viewed over one million times, incurred the wrath of other prominent doctors who claimed he was encouraging people to abandon sunscreen and drive up rates of skin cancer. This 'faux pas' was, he was warned, 'frighteningly inaccurate' and could cause 'huge damage'.

One, palliative care specialist and author Dr Rachel Clarke, who goes by the handle @doctor_oxford and has almost 300,000 followers on the platform, wrote: 'Deeply troubled to see a doctor with a platform such as yours, Tim, encouraging people to stop using sunscreen when a mountain of evidence demonstrates the link between UV exposure & malignancies such as melanoma.

'More bluntly, why are you being so grossly irresponsible?'

Adam Kay, whose bestselling book This Is Going To Hurt, about his experiences as a junior doctor, was turned into a BBC drama starring Ben Whishaw, added: 'Bad news for people using the ZOE thing – your god doesn't seem to understand medicine.'

Even the co-author of the study Prof Spector was referring to got stuck in. Prof Caetano Reis e Sousa, of the Francis Crick Institute, said: 'Sunlight can help our bodies make Vitamin D but sun exposure is also a clear risk factor for skin cancer. As we can also get Vitamin D from diet, it is easy to avert possible Vitamin D deficiency while minimising harmful exposure to sunshine.

'Our study does not suggest that the application of sunscreen is in any way detrimental to health.'

For his part, Prof Spector stood firm – not only referring critics to his 30 years of research on Vitamin D but citing the expertise of his wife, dermatologist Dr Veronique Bataille, who he had consulted before making his post. Today, both Prof Spector and Dr Bataille are speaking to The Mail on Sunday to defend his comments. Both have been left 'shocked' about the 'venom' they provoked.

After all, Prof Spector did not say everyone should abandon sunscreen. Rather, as he explains, he believes most people living in the UK don't need to wear it every day. 'People should use sunscreen to prevent sunburn, and the risk of cancer is absolutely clear,' Prof Spector says. 'I use it myself. But I absolutely wouldn't be using it in January in Glasgow.

'The main sentiment is not that sunscreen is bad – but using sunscreen in winter for most people is bad, and may have other undesired effects. Being deficient in Vitamin D has consequences for people. 

The mouse study I referred to only adds to the evidence we already have that it increases the risk of recurrence for a range of cancers, including skin cancers, and that if people with melanoma do spend time in the sun it reduces the risk of it coming back.'

Tim's social media post suggesting that we don't all need year-round sunscreen

In other words, being exposed to a bit of sunlight – without sunscreen – is good for our health. This, however, flies in the face of what Prof Spector describes as a creeping 'anti-sun' trend which recommends everyone wears sun cream all year round. It's a view held by US authorities such as the Centers for Disease Control and Prevention (CDC) and the American Academy of Dermatology.

Interestingly, the NHS and the British Association of Dermatologists take a less stringent approach.

They simply point out that the sun is strongest between March and October, encourage using a sun cream of at least factor 30 (they don't say when or where) and recommend staying out of direct sunlight between 11am and 3pm. Yet the US messaging has filtered down into the cosmetics industry, which in turn has been boosted by beauty influencers on TikTok and Instagram.

Prof Spector points to adverts for moisturisers and cosmetic creams which contain SPF 50. One, from popular brand CeraVe, sold in all high street chemists and most major supermarkets, says: 'Not just a summer fling. Fall in love with wearing SPF daily.'

Prof Spector says: 'In my mind, and in the mind of many dermatologists, that's completely unnecessary. I don't see the rationale.

'It reminds me of the food industry, convincing people they need all sorts of things added to their diets. Now it's cosmetics companies who are trying to get young people to wear SPF all year round with the message that, if they don't, they'll get wrinkles or skin cancer. For most people it's not true. And this one-size-fits-all approach is unhelpful.'

For the scientific detail on this, Prof Spector defers to his wife, who he describes as a 'world expert in melanoma and risk factors including sunshine'.

Dr Bataille, a dermatologist who practices both in the NHS and privately, agrees that this perception that sunscreen must be worn at all times 'has just snowballed without evidence to justify it'.

'There are no studies which suggest that using sunscreen in winter in the UK has any benefits at all – and it may well be causing us problems,' she says.

Dr Bataille acknowledges the wealth of evidence that shows excessive UV exposure causes skin cancer. Rates of melanoma, the most worrying type, have increased 32 per cent in a decade, and are set to rise further. Sunscreens reduce the risk.

But laboratory studies show they can also block Vitamin D production, Dr Bataille says.

This generally isn't a problem in the summer because studies show that, out of the labs, we don't apply it well enough to totally block out all the rays. It means we do actually produce Vitamin D.

Sunlight triggers the production of Vitamin D in our bodies, and wearing sunscreen throughout the year may affect the amount of the crucial compound we are able to generate

She explains: '[In summer] more of our skin is exposed because it's hot, we miss patches when applying sunscreen so UV still gets through, and we don't reapply enough. This means our bodies can still generate Vitamin D.'

The general trend towards recommending higher SPF creams is linked to this finding. Experts say 'typical use' of SPF 50, for example, probably gives an actual SPF of 15. But we know that those who are most diligent at using sunscreen and covering up are also the most likely to be Vitamin D deficient.

It's well-accepted that none of us generate much Vitamin D from sunlight during the winter. This is because levels of UVB – a type of ultraviolet radiation in sunlight that triggers Vitamin D production in the skin – are lower in winter as the Northern Hemisphere is angled away from the sun.

Such is the concern about low levels that since 2020 the NHS has recommended everyone takes a daily supplement. And it means most people stand to benefit from not wearing sunscreen at times when they're far less likely to burn, in winter.

'You might only have your hands sticking out of your clothes, unless you've got gloves on, and a bit of your face which even then might be obscured by a hat or scarf,' says Dr Bataille. 'You might not be outside for long, and even ten to 15 minutes of UV will be beneficial to top up some Vitamin D. There's no evidence this low amount of UV will harm you, but Vitamin D deficiency and using too much sunscreen might.'

Lower levels of Vitamin D are linked to a greater risk of heart disease, poorer survival from breast cancer and poorer bone health. Even in people with melanoma, lower Vitamin D is associated with 'poorer outcomes and thicker tumours, a measure of disease severity,' adds Prof Spector.

A more acute issue is the 'epidemic' of skin problems dermatologists are seeing from increased sunscreen use.

Dr Bataille says her clinic is full of women in their 30s and 40s with 'congested' skin, psoriasis and acne and a painful condition called perioral dermatitis, which causes a rash in the middle of the face.

'When we ask about their skincare routines, they're wearing SPF50 every day. People researching the skin microbiome believe sunscreen damages it. Yet companies are producing moisturisers and make up with SPF included and telling women they need sunscreen every day.

'These women are getting their information from TikTok and Instagram, and women are slapping on SPF because they're worried about ageing, not skin cancer. Ironically, it's damaging their skin in different ways.'

In addition to all this, evidence suggests that we may not absorb Vitamin D as efficiently when it's in supplement form.

One big trial involving 26,000 adults who were given either a Vitamin D tablet or a placebo and followed for five years found no benefits for a range of health conditions including strokes, cognitive function, cancer or heart disease. 'People should stop taking Vitamin D supplements to prevent major diseases or extend life,' it concluded.

Dr Bataille says: 'People working in the field of Vitamin D say we were engineered as humans to synthesise it naturally through our skin, and taking it in pill form might not be as effective. It may not be equivalent to 15 minutes of sunshine.'

And that, after all, is what is being recommended.

Neither Dr Bataille nor Prof Spector advocate going outside in summer sun without sunscreen – especially if you're fair-skinned. Most of Dr Bataille's skin cancer patients are, she says, those who 'have really overdone it and damaged their skin following years abroad, never wearing sunscreen'.

'If people are sensible and wear sunscreen in summer, there's far less to worry about than the generation I'm seeing now,' she adds.

Research suggests the dose you need to get enough Vitamin D is below the threshold for sunburn, and that just ten to 15 minutes of daily exposure for most people – and up to 40 minutes for those with darker skin – is enough.

'We need to personalise advice,' Prof Spector says. 'Some people, including those with a family history of melanoma, pale skin and freckles, and lots of moles, do need to be more careful if they're planning to be in the sun for long periods. But even for them, wearing SPF50 all year round is likely to be excessive – and may leave them deficient in Vitamin D.'

Two in three Australians will be diagnosed with some form of skin cancer before the age of 70.

No such thing as a safe tan

There is no safe or healthy way to get a tan, according to the NHS. It also warns that being tanned does not protect people from the sun's harmful effects.

Instead the NHS suggests that, when spending time in the sun, Britons should wear sunscreen that has a sun protection factor (SPF) of at least 30. On the label it should also say it has at least a four-star UVA protection. This is a scale, from 0-5, that shows how much protection the product provides against damaging UVA rays.

It is worth checking that the sunscreen is not past its expiry date, as the cream can lose its effectiveness

The NHS suggests that, when spending time in the sun, Britons should wear sunscreen that has a sun protection factor (SPF) of at least 30

Sunscreen should also be applied again immediately after going in water – even if the label says it is water resistant

The NHS also provides clear information on how to correctly apply it. Adults should aim to use around six to eight teaspoons of sunscreen if they're covering their entire body. And when spending an extended period of time in the sun, it should be applied twice – 30 minutes before going out and then again just beforehand.

Sunscreen should also be applied again immediately after going in water – even if the label says it is water resistant. Extra care should be taken with children, as their skin is more sensitive – parents are advised to ensure that children cover up in suitable clothing as well as wearing SPF 30.

Children aged under six months should be kept out of direct strong sunlight.