For today’s edition of Dear Mark, I’m answering two questions. First up concerns the effect going Primal has on your skin’s resistance to sun damage. While there isn’t any specific research examining ancestral eating and sun damage, several lines of evidence suggest a protective effect. Second, what’s the deal with stigmasterol, AKA Wulzen anti-stiffness factor? The WAPF says butter and cheese and milk are the best place to get it, but that pasteurization destroys it. Is this really true? And how does fermentation affect stigmasterol?