How did people in the Arctic in the distant past deal with no sun in winter and weak sun the rest of the year? Did food provide vitamin D?
Roger Williams, Lucerne, Switzerland
According to the US National Institutes of Health, 100 grams of salmon or trout provides enough daily vitamin D for adults of most ages. This wouldn’t have been hard for a hunter-gatherer to find in Arctic Scandinavia, North America or Russia.
Guy Cox, School of medical sciences, University of Sydney, Australia
The major dietary source of vitamin D is oily fish, which was, and is, a staple …