The Dangers of Sun Exposure
Table of Contents
Yes, the warmth of the sun on our skin feels good, especially during our often gloomy weather, but people underestimate the risks associated with excessive sun exposure:
- Skin Damage and Premature Aging: UV rays from the sun will damage the DNA in our skin cells, giving way to premature ageing. Things like wrinkles, age spots, and a loss of skin elasticity are all possibilities.
- Increased Risk of Skin Cancer: Prolonged and unprotected sun exposure raises the risk of developing various types of skin cancer, including melanoma, the most dangerous form.
Why Dermatologists Recommend Sun Protection
Given these risks, it’s no surprise that dermatologists strongly push for sun protection. This typically includes using broad-spectrum sunscreens, wearing protective clothing, and avoiding the sun during peak hours.
The Importance of Vitamin D
It seems like sun protection is vitally important, but can we ignore the vital role that vitamin D plays in our health?
- Role in Health: Most people know Vitamin D is essential for bone health, helping our bodies absorb calcium. Arguably, less people know about its role in immune function and that it has been linked to reduced risks of various diseases.
- Prevalence of Vitamin D Deficiency in the UK: Due to our northern latitude and often cloudy weather, vitamin D deficiency is surprisingly common in the UK. Depending on ethnicity, between 12% and 53% of adults are classed as vitamin D deficient. (1)
- Consequences of Vitamin D Deficiency: Low levels of vitamin D can lead to bone pain, increased risk of fractures, and in severe cases, conditions like rickets in children or osteomalacia (soft bones) in adults. It’s also been associated with an increased risk of respiratory infections. Scientists are making studies that hint that many other diseases and disorders are caused by vitamin D deficiency, including schizophrenia (2), depression, and certain neurological conditions. (3)
We have found many other examples but we should make it clear that studies use language such as ‘possible implication’, and ‘further research is needed’, which make it difficult to find definitive advice. Saying that, Public Health England recommends, at least in the autumn and winter months, that people take a supplement.
Sources of Vitamin D
Sunlight is the most well-known source of vitamin D, but it’s not the only way to ensure adequate levels:
- Sunlight Exposure: When UVB rays from sunlight hit our skin, it triggers vitamin D production. The amount produced can vary based on factors like skin tone, time of day, season, and latitude.
- Dietary Sources: Some foods naturally contain vitamin D, including fatty fish (like salmon and mackerel), egg yolks, and mushrooms. In the UK, certain foods are fortified with vitamin D, such as some breakfast cereals and dairy products.
- Supplements: Vitamin D supplements are widely available and can be an effective way to maintain adequate levels, especially during winter months or for those with limited sun exposure.

Balancing sun protection with vitamin D
From general knowledge, speaking with friends and patients, we get the idea that people, in general, are under-protected from the sun. People forget to reapply sunscreen and miss bits of their body, they underestimate the strength of the UV rays, and they don’t realise the amount of UV they receive indoors and in cars, both through the sunroof and the side windows. That being said, in the context of this article, UVB is the wavelength that provides the energy to make vitamin D, and is mostly blocked by glass.
How much sun is recommended to get an adequate amount of vitamin D?
- Sport Scotland recommends 15-20 minutes a day, Healthline suggests 10-30 minutes several times a week, and NCBI states 9 minutes daily. All three suggest midday and/or direct sunlight for their given time amounts.
Safe Sun Exposure Guidelines: Short periods of sun exposure, particularly in the middle of the day, can help with vitamin D production. The exact time needed varies based on skin tone, with darker skin requiring more time.
Alternatives to Sunlight: For those at high risk of skin cancer or those who prefer to avoid direct sun exposure, a combination of dietary sources and supplements can help maintain vitamin D levels.
Personalised Approaches: The right balance will vary from person to person based on factors like skin type, family history of skin cancer, occupation, and lifestyle. It’s important to consider these individual factors when determining the best approach.
So, considering the slightly varying sun exposure advice, with regards to vitamin D, 10 or so minutes of direct midday sun is enough. If we take this advice as read, and it does not account for other periods of sun exposure, such as morning and evening, and indirect sun exposure, then the number of 10 minutes or so will be less. It looks like most people will be getting enough. But, if you are spending all of the day indoors, religiously covering up, and applying suncream diligently then possibly you are not generating enough vitamin D. Another factor to mention is that SPF 30 lets around 3% of UVB rays through to the skin.
With all the evidence weighed up we would say keep applying and maybe increase sun cream application and not be concerned about the effect it may have on your vitamin D levels. Unless you are not averaging 10 mins a day in the sun, and are not eating enough vitamin D containing foods. If you are concerned about your vitamin D levels you can ask your doctor for a simple blood test.

References
Lin L, Smeeth L, Langan S, et alDistribution of vitamin D status in the UK: a cross-sectional analysis of UK BiobankBMJ Open 2021;11:e038503. doi: 10.1136/bmjopen-2020-038503 Link to article
Ghazaleh Valipour, Parvane Saneei, Ahmad Esmaillzadeh, Serum Vitamin D Levels in Relation to Schizophrenia: A Systematic Review and Meta-Analysis of Observational Studies, The Journal of Clinical Endocrinology & Metabolism, Volume 99, Issue 10, 1 October 2014, Pages 3863–3872. Link to article
Plantone D, Primiano G, Manco C, Locci S, Servidei S, De Stefano N. Vitamin D in Neurological Diseases. Int J Mol Sci. 2022;24(1):87. Published 2022 Dec 21. doi:10.3390/ijms24010087 Link to article