>The thing is I don't believe we need 24 hours exposure to sunlight in order to get enough vitamin D, let alone >full-body exposure. And palaeos certainly get enough vitamin D in their diets. I mean, I, for example, eat c.20 >extra-large raw wildcaught oysters, rich in vitamin D, almost every fortnight. As for sunblock, that's only used >in the summer, and not everyone uses it, mostly it's just women who do.

Geoff, you may eat the oysters regularly, but did paleos? Especially those in northern climes? I don't think you can assume vitamin D was available to all primitives at all times. Obviously we developed (or didn't lose) the ability to synthesize it for a reason.

Apparently you have not been around sunny areas where 90% of the population use sunblocks most of the year. Also true of sunny ski resorts throughout the winter.