I’d like to ask about sun exposure versus skin cancer. Personally, I have a history of melanoma in my family, and I’ve been avoiding sun because of it for a long time.

Chris Kresser:   We’re going to talk about it in detail when we cover vitamin D in the blood chemistry unit. Interestingly enough, if you consider sun exposure, UV, like a U-shaped curve, it’s like many other nutrients in the sense that too little is harmful, and too much is harmful. With melanoma, lack of sun exposure can be a contributing factor, and excessive sunscreen use can be a contributing factor because it blocks—it doesn’t do a particularly good job of blocking UVA, which is what causes skin cancer, but it blocks UVB, which is what produces all of the benefits that we get from UV exposure, and that goes far beyond vitamin D. There are immunoregulatory benefits, nitric oxide production, many neuropeptides that are produced when we’re exposed to UVB, and we don’t get that when we have sunscreen on. So, generally, you certainly want to avoid getting sunburned, but avoiding the sun entirely is potentially more dangerous than even getting sunburned. I actually have an article coming out about that in the near future, so take a look.