It is scientifically proven: exposure to UV sun rays could be beneficial for your health. But you still have to keep your sunscreen at hand.
Browning the pill in the sun has been considered bad for health for at least four decades. The main risk comes from ultraviolet light (UV), which the sun emits at the same time as its visible radiation. Rays that can increase the risk of skin cancer – the number of diagnoses of which are increasing – and lead to premature aging as well as the appearance of wrinkles. This is why most developed countries recommend sun lovers to protect their skin in the heat of the day using a sunscreen, especially during the summer months.
And if UV-related risks are real, new research suggests that it may be time to consider the advantages.
According to a recently published study in Health and Placean increased exposure to UV therefore seems to considerably reduce the risk of dying of cardiovascular disease or cancer. The risk of dying of melanoma, the deadliest form of skin cancer, has not changed significantly with exposure to UV. Although smaller studies have already reported health benefits, this is the largest study to show a direct correlation between UV exposure and the extension of lifespan.
To carry out their analysis, researchers from the University of Edinburgh used data with more than 360,000 people appearing in the UK Biobank database. They identified two cohorts more likely to be strongly exposed to UVs: those who declared to use solar benches or sunbathing lamps and those who lived in sunny places.
To verify that their hypotheses concerning the exposure of UV subjects were correct, scientists also examined the levels of vitamin D in a subset of blood samples. Vitamin D being synthesized in the skin in the presence of certain forms of UV radiation, it constitutes a reliable indicator of solar exposure.
Researchers then examined the mortality rates of subjects taking into account other factors such as age, sex, smoking and socio-economic status (in Great Britain, people who live in sunny climates are generally richer). They also took into account physical exercise, because some followers of sun exposure could lead a healthier outdoor life.
Their analysis has shown that solar bench users had 23% risk in less to die from cardiovascular disease and 14% risk in less to die of cancer, compared to non-users.
Similar trends have been observed according to the place of residence. A resident of Truro, for example, in the south of Great Britain, undergoes an average of 25% of more solar radiation with short waves (a measure which includes UV, visible light and part of the infrared light) in a year than a resident of Glasgow or Edinburgh, who are much further north. The team concluded that this was reflected in a 19% decrease in the risk of dying of cardiovascular disease and 12% of the risk of dying of cancer.
In other words, solar bench users have experienced an average of 48 days more than non-users during the 15 years of the study. The corresponding figure for people living in sunny places was 26 days.
The sun’s rays, secret asset for health?
According to Richard Weller, who has co -edited this research, most advice on exposure to UVs have so far been firmly focused on prevention of melanoma skin cancer. But, he says, “many more people die from other cancers and diseases”.
“We have to think about how UV rays could help them avoid the disease.”
The exact mechanism by which UV light could prolong life is unknown.
The authors, for their part, believe that part of the explanation could reside in the ability of vitamin D to strengthen the immune system and improve bone health. They also evoke nitric oxide, a powerful amplifier of blood vessels capable of reducing the risk of cardiovascular disease. Research published in the Journal of Investigative Dermatology In 2014 showed that nitric oxide is released in skin cells which have been moderately exposed to certain UV rays, and that sunlight contributes to passing it through the circulatory system where it could have beneficial effects on health. Researchers hope that future studies will further clarify the causal chain.
Other questions deserve an answer. On the one hand, the Dr Weller team could only analyze the data of individuals living in Great Britain: different attitudes with regard to the risks and benefits of sun exposure could appear in other places. Due to the data structure, they were not able to control the use of solar creams either.
But above all, they only studied participants of mainly white ancestry, in order to ensure that the reaction to UV was consistent. “We know that the color of the skin influences the body’s response to UV, but we don’t yet know how,” said Dr. Weller. Darker skin people are the most exposed to the risk of vitamin D deficiency, it is necessary to deepen research on the way in which UV exposure affects this population, declares Frank de Grujl, professor emeritus of dermatology at the medical center of the University of Leyde. “We have to look at biology.
New research could encourage scientists and health experts to examine more in depth the advantages of UV exposure compared to their risks and, perhaps in the future, to give more nuanced advice on how different groups of people can protect themselves from the sun.
But for the moment, experts agree that the study is not An authorization to stop wearing sunscreen.