Sunlight, Health and Modern UV Policy: A Balanced Approach for Australia

Geoff Acton
3 days ago
4 min read

Based on analysis from the Australian Sunscreen Council (ASC) and the foundational research presented in Richard B. Weller’s “The Systemic Health Benefits of Sunlight: Beyond Vitamin D” (Journal of Investigative Dermatology, 2024), with additional commentary by Advance ZincTek.

Australian sun safety messages have traditionally centred on reducing exposure to ultraviolet radiation to prevent skin cancer. This approach has been grounded in strong epidemiological evidence and has delivered major public health benefits. However, emerging international research shows that sunlight influences human physiology far more broadly than previously recognised. As this evidence grows, there is an opportunity for Australia to take a more complete view of how sunlight affects long-term health and how public guidance might evolve to reflect both risks and systemic benefits.

Revisiting the Scientific Understanding of Sunlight

A 2024 review by Weller challenges the traditional, skin-focused perspective on UV exposure. He observes that “medical attitudes to sunlight have changed in the last century” and argues that “the current dermatology approach to sunlight only considers skin health, in particular risks of skin cancers and photoaging, and fails to take into account systemic health benefits” (Weller, 2024). This shift in thinking reflects a significant expansion of evidence linking sunlight to cardiovascular regulation, metabolic processes, immune activity and overall mortality.

Mortality Patterns in Large Cohort Studies

Two major long-term cohort studies provide compelling epidemiological evidence that sunlight may influence overall survival.

The Melanoma in Southern Sweden cohort reported that “sun-seeking behaviour was inversely correlated with all-cause mortality, despite a higher incidence of melanoma” (Lindqvist et al., 2014). Participants who received more sunlight experienced lower mortality, even with a modest increase in melanoma diagnoses.

Similarly, the UK Biobank analysis involving 377,000 participants concluded that “increased sun exposure correlates with reduced all-cause mortality, particularly related to reduced cardiovascular mortality but also cancer mortality” (as summarised in ASC, 2025). This pattern suggests that sunlight may affect systemic pathways that contribute to long-term health outcomes.

Weller summarises these findings by stating that, within the populations studied, “the benefits of sunlight exposure outweigh the risks” (Weller, 2024). While this conclusion is specific to the regions examined, the underlying biological mechanisms may be relevant across broader contexts, including Australia.

Nitric Oxide and the Limitations of Vitamin D Supplementation

Vitamin D has often been assumed to explain the positive health associations linked to sunlight, yet multiple controlled trials have shown that supplementation does not consistently reduce cardiovascular disease or hypertension. This has prompted researchers to investigate alternative mechanisms.

One pathway involves nitric oxide, which is stored in the skin and released into circulation following UVA exposure. Weller notes that “UVA irradiation of human volunteers mobilizes nitric oxide from cutaneous stores to the circulation where it lowers blood pressure through arterial dilatation” (Weller, 2024). This effect has been demonstrated in several independent studies, indicating that sunlight influences vascular function in ways that cannot be replicated by oral vitamin D alone.

Given that hypertension is the leading cause of global mortality, the potential role of sunlight in cardiovascular regulation is significant and warrants further investigation.

Sunlight, Immune Function and Infectious Disease Trends

Research also suggests that UV exposure may influence immune activity. During the COVID-19 pandemic, several studies observed strong seasonal and geographical patterns in infection and mortality rates. Some analyses reported that “COVID-19 mortality correlated inversely with local UV environment” (Cherrie et al., 2021). These patterns were observed across multiple countries, strengthening the hypothesis that sunlight may affect immune regulation.

Experimental work supports this idea by showing that UV exposure can activate components of the innate immune system and modulate inflammatory pathways. Although these mechanisms are still being clarified, the convergence of epidemiological and laboratory evidence highlights sunlight’s broader relevance to immune health.

Implications for Australia

Australia’s long-standing sun protection campaigns have delivered substantial public health benefits, and protective behaviours remain essential in our UV environment. However, several scientific bodies now advise that sunlight’s systemic effects should be reflected in national guidance.

The United Nations Environmental Effects Assessment Panel (2023) and a 2024 expert review endorsed by the Cancer Council and the Australasian College of Dermatologists both acknowledge that sunlight has beneficial physiological effects that warrant inclusion in policy discussions. This does not reduce the priority of skin cancer prevention. Rather, it indicates that public messaging should reflect the full evidence base, including emerging findings on cardiovascular and immune pathways.

Key Considerations for Future Public Health Guidance

These points outline important themes that may support a more complete national approach to sunlight and UV exposure.

1. Sunlight produces systemic effects that extend beyond vitamin D.

These include cardiovascular, metabolic and immune pathways supported by a growing body of evidence.

2. Public health advice may benefit from a more nuanced approach.

People experience different levels and patterns of UV exposure based on their environment, work and lifestyle. Acknowledging this variation may lead to more effective communication.

3. Sunscreens remain essential for prolonged or unavoidable exposure.

Non-nano zinc oxide-based sunscreens continue to provide reliable broad-spectrum protection.

4. Early detection should remain a central element of prevention.

Regular skin monitoring and screening significantly reduce the impact of melanoma and non-melanoma skin cancers.

5. More Australian research is needed to guide local policy.

Understanding how these international findings apply in Australia will support evidence-based decision-making.

Conclusion

Sunlight is a biologically active environmental factor that influences multiple physiological systems. Excessive or unprotected exposure increases skin cancer risk, yet moderate sunlight exposure appears to support cardiovascular and immune health in important ways. Australia’s public guidance can evolve to reflect both aspects of the evidence while maintaining strong preventive measures.

A balanced approach that combines effective photoprotection, early detection and updated public messaging can support both systemic wellbeing and skin health.

References

1. Australian Sunscreen Council (ASC). (2025, October 23). Rethinking sunlight: Why Australia needs a balanced approach to UV exposure. https://www.australiansunscreencouncil.org/post/rethinking-sunlight-why-australia-needs-a-balanced-approach-to-uv-exposure

2. Cherrie M, Clemens T, Colandrea C, et al. Ultraviolet A radiation and COVID-19 deaths in the USA with replication in England and Italy. Br J Dermatol. 2021;185(2):363-370.

3. Lindqvist PG, Epstein E, Landin-Olsson M, et al. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014;276(1):77-86.

4. Weller RB. The systemic health benefits of sunlight: beyond vitamin D. J Invest Dermatol. 2024. Available at: https://www.jidonline.org/article/S0022-202X(24)00280-X/fulltext