Which Sunscreens Are Safest?
The question of sunscreen use is perennial. I'm just relieved that it's finally warm and sunny enough to be having this conversation, after such a hard winter. When making decisions about sunscreens, there are several factors to consider.
First, some experts now recommend that you attempt to get 30 minutes of sunshine exposure, twice a week, to boost your vitamin D levels naturally. In the summer, in the northern latitudes, it takes about 15 minutes in noonday sun for your skin to generate a healthy amount of the "sunshine vitamin." Vitamin D is actually a prohormone. Vitamin D3, which is generated beneath the skin in response to sunlight, is changed by the liver and kidneys to become a hormone-like compound that plays many important roles in the body.
We know this, because there are receptors for the vitamin D molecule on virtually every tissue in the body. They're there because they fit into these receptors like a key in a lock. When the key is "turned" the affected cell undergoes a change that impacts overall health. Research shows that people with higher levels of vitamin D are significantly less likely to succumb to cardiovascular disease, for example. And there's some evidence that vitamin D is an essential component of the immune system, which helps protect you against everything from infections to cancer. Vitamin D is also linked to good mental health. So adequate vitamin D status is essential.
On the other hand, too much ultraviolet radiation from sun exposure is linked to a greater risk of skin cancer. Melanoma, for instance, is the deadliest of skin cancers, and it's believed to be directly related to sunburn and sun exposure. So if you're going to be spending lots of time out of doors, sunscreen is crucial to avoid sunburn and skin cancer. Next week, I'll talk more about sunscreens; how they work, which ones are safest, and when you should use them.