From the Guidelines
Sunscreen does not typically cause vitamin D deficiency when used normally, as most people do not apply it thoroughly enough to completely block UVB rays necessary for vitamin D synthesis. When considering the impact of sunscreen on vitamin D production, it's essential to understand how vitamin D is synthesized in the skin. According to a study published in Circulation Research in 2018 1, endogenous vitamin D-hormone synthesis occurs through ultraviolet light exposure of 7-dehydrocholesterol within the skin, resulting in the conversion into cholecalciferol (D3). This process can produce tens of thousands of units of cholecalciferol in light-skinned individuals with just 15 minutes of sun exposure per week on the face and arms.
Some key points to consider:
- Most people do not apply sunscreen correctly or frequently enough to completely prevent vitamin D production
- Brief sun exposure of unprotected skin (5-15 minutes a few times per week) can provide adequate vitamin D
- Vitamin D can also be obtained through dietary sources, such as fatty fish, fortified dairy products, and egg yolks, or through supplements (typically 600-800 IU daily for adults)
- The benefits of sunscreen in preventing skin cancer and premature aging outweigh the potential impact on vitamin D status
Given the available evidence, the use of sunscreen is not a significant cause of vitamin D deficiency, and its benefits in preventing skin cancer and premature aging should not be compromised. Instead, individuals concerned about their vitamin D levels can explore alternative sources of vitamin D, such as dietary changes or supplements, while continuing to use sunscreen as directed.
From the Research
Sunscreen and Vitamin D Deficiency
- The relationship between sunscreen use and vitamin D deficiency is complex, with various factors influencing vitamin D production, such as season, latitude, skin color, and sun protection 2, 3, 4.
- Sunscreen use can prevent skin cancer, but there are concerns that it may increase the risk of vitamin D deficiency 5.
- However, the weight of evidence from field trials and observational studies suggests that the risk of vitamin D deficiency due to sunscreen use is low 5.
Factors Influencing Vitamin D Production
- Latitude, season, skin color, and sun protection determine UV absorption and vitamin D production 2, 3, 4.
- Sunscreen use, particularly broad-spectrum sunscreens, can prevent erythema but is unlikely to compromise vitamin D status in healthy populations 6.
- Other factors, such as time of day, altitude, air pollution, and aging, also influence sun-induced vitamin D synthesis 4.
Sunscreen Use and Vitamin D Status
- Experimental studies suggest that sunscreen can block vitamin D production in the skin, but use artificially generated ultraviolet radiation with a spectral output unlike that seen in terrestrial sunlight 5.
- Observational studies mostly found no association or that self-reported sunscreen use was associated with higher 25(OH)D concentration 5.
- Judicious use of daily broad-spectrum sunscreens with high ultraviolet (UV) A protection will not compromise vitamin D status in healthy people 6.
Recommendations
- Vitamin D screening should be restricted to those at risk of hypovitaminosis, such as patients with photosensitivity disorders, who require rigorous photoprotection 6.
- Screening and supplementation are advised for individuals with photosensitivity disorders 6.
- Public health sun protection guidelines should still be implemented to reduce skin cancer, and sunscreen use should be recommended in conjunction with other forms of sun protection, such as clothing and shade-seeking behavior 2, 6.