Itchy Feet

Vitamin B12 deficiency was once known as pernicious anemia, which would begin with lethargy and then continue on towards complete prostration. I seem to recall reading that wards used to be found full of such cases in larger zones, until a doctor (some time in the 20s) noticed slight improvements in people who had eaten yummy liver. After force-feeding liver to comatose victims, they were up and running about within weeks. It took another few years to figure out exactly what in liver was missing when it wasn't eaten, but vegetarians need not panic. B12 is now mostly made (at least in North America) by Eastman Kodak, who used their massive knowledge of fancy organic synthesis (developed for the photo chemical industry) to become an almost-monopoly supplier of vitamins to just about everyone (including, I suspect, many 'natural medicine' suppliers who chirp on constantly about how much better their products ffrom those made by large evil drug companies).