You probably think of the health effects of sunlight as a mixed bag. On the one hand, sun exposure helps your body make vitamin D. But on the other, it can cause skin cancer. To get around this conundrum, dermatologists frequently recommend avoiding sun exposure when you can, slathering on sunscreen when you can't, and taking a vitamin D supplement to make up for the lack of sunlight in your life. Yet in seeking to solve one problem, this advice may open up many others and be contributing to ill health in the West. Today on the show, Rowan Jacobsen, a science journalist who has spent years investigating the health impacts of sunlight, will unpack the underappreciated benefits of sun exposure, and that, crucially, they're not primarily a function of the production of vitamin D and can't be replaced with a pill. We talk about what else is at work in ultraviolet radiation's positive effects on blood pressure, autoimmune diseases, insulin resistance, mood, and more. We also get into how to weigh these benefits against the risk of skin cancer, why health officials in Australia, which has the highest rate of skin cancer in the world, have changed their recommendations around sun exposure, and if there's a role sunscreen should still play in your routine.