Is avoiding the sun healthy? Expert criticism of the 'No sun policy'

From warning to nuance?

In recent decades, advice regarding sunlight has mainly focused on avoiding UV radiation, primarily because of the risk of skin cancer. But is this 'no sun policy' in line with growing scientific insights into the health benefits of sunlight and, in particular, UV radiation? In response to this, an international conference was organized in 2024. This meeting brought together leading researchers, such as dermatologists, immunologists, etc., to share the latest data and insights on the health benefits of UV light.

The evolution of solar advice

The debate about sunlight and health has been going on for almost a century. In 1928, UV radiation was recognized as carcinogenic, and public health policy focused on limiting exposure to it. Interestingly, in the 1940s, a link was established between more sunlight and lower cancer mortality. From the 1950s until now, a "no sun policy" has emerged, particularly in Western countries, to prevent skin cancer. Only in recent years has there been a growing awareness that this focus may be too one-sided and that moderate exposure to sunlight also has important health benefits, especially in countries with few hours of sunshine.

Key research findings

•      Epidemiological studiesshow that people who are more exposed to sunlight or UV radiation are less likely to die from cardiovascular disease and cancer. This effect has been most strongly demonstrated in large cohort studies from Scandinavia and the UK, where the difference in life expectancy between people with little and high sun exposure was similar to the difference between smokers and non-smokers.
  
  
  
•      Research shows that the benefits of UV radiationare not solely attributable to vitamin D. UVB from sunlight stimulates the production of vitamin D, which is important for strong bones and a healthy immune system. In addition, UV light activates other processes: UVA causes the release of nitric oxide (NO) from the skin, which lowers blood pressure and reduces the risk of cardiovascular disease. UV radiation also activates pathways in which the brain, hormones, and immune system work together. These pathways influence the immune system in various ways and may potentially reduce the risk of autoimmune diseases.
  
  
  

       Sunlight versus vitamin D supplementation: Although vitamin D deficiency is associated with a higher risk of disease and mortality, large studies with supplements show little effect of extra vitamin D on health outcomes other than bone and dental health. This suggests that sunlight itself—and not just vitamin D—offers health benefits.

Importance for public health and policy

The authors argue for a change in public health policy, especially in northern countries. Current recommendations are often based on the experiences of people with fair skin in sunny countries (such as Australia), whereas in countries with little sun, the health benefits of increased sun exposure appear to outweigh the risk of skin cancer. They recommend more nuanced information tailored to skin type, location, and season, and call for more research into safe forms of UV exposure, such as controlled light therapy.

In summary

This article is the result of an international collaboration between experts who want to reassess the balance between the risks and benefits of sunlight. They base their findings on the latest epidemiological, clinical, and mechanistic studies and call for a more balanced, specific approach to sun exposure advice, especially in countries with little sunlight. In this regard, it is essential to consider both public health and individual differences.

The health benefits of sunlight therefore go beyond vitamin D alone and cannot be fully replaced by supplements.