Hacker News Reader

Can’t find a citation at the moment, but it also depends on what part of your body is exposed. Just resting your forearm on an open car window won’t do it. You have to expose your torso mid-day IIRC.

https://www.healthline.com/nutrition/vitamin-d-from-sun#time...

View on HN

Just as a pure speculation (I am not specialized in this area) I find it a little bit odd that forearm is not enough as I find it is the most common area exposed to sun by people at least in the last 100.000 years.

So I am wondering how come in this case selection did not chose those whose forearms can produce a lot of Vitamin D as it was probably the most exposed part to the sun.

Don't forget that many people used to bathe outside for many millenia. But I too would be interested in how clothing through generations have put selective pressures on humans, if any.

Reply on news.ycombinator.com