Here in the UK most parts have enjoyed a hot and sunny weekend. Yesterday, I spent a good portion of the day out in the sun, and there was a distinct whiff of sunscreen in the air. But it wasn’t coming from me: For some years now, I’ve been wary of using this form of sun protection, ever since I learned that their use is associated with an increased risk of malignant melanoma.
One of the theories put forward to explain this association concerns the fact that sunlight comes in two main forms: ultraviolet A (UVA) and UVB. UVB is essentially responsible for sunburn, and sunscreens are essentially designed to shield us from it. That’s all fine and well, except that sunscreens do not generally protect against UVA which is believed to promote the development of skin cancer including malignant melanoma. The result: that the enhanced sunlight exposure afforded to us by sunscreens increase our exposure to UVA and skin cancer.
This is one of the reason why when I wrote about the broad benefits of sunlight exposure on 4th April this year, I did not mention sunscreens when advising about the steps that nonetheless should be taken to avoid burning. At this time, my recommendation in this area if for us to seek shade and use suitable clothing when appropriate. This, of course, is particularly important for those who have fair skin.
The reason that I am writing this is because I noticed over the weekend a story about a class action suit that is underway in the Los Angeles Superior Court. The law firm Lerach Coughlin is accusing five leading manufacturers of sunscreen of misleading their customers regarding the supposed cancer-protective properties of their products. One of Lerach Coughlin’s lawyers, Samuel Rudman, is quoted in The Times as saying: Sunscreen is the snake oil of the 21st-century.
The Times article in which this quote appears looks at some of the issues associated with the development of UVA-blocking sunscreens. It also lists some products that claim to have UVA-quelling ability. Personally, I remain cautious about the use of such products: sunscreen use can reduce body levels of vitamin D [1] – a nutrient that (as I was keen to point out on 4th April) has broad cancer-protective properties.
References:
1. Matsuoka LY, et al. Chronic sunscreen use decreases circulating concentrations of 25-hydroxyvitamin D. A preliminary study. Arch Dermatol. 1988;124(12):1802-4.
