Perhaps the only advantage of getting old is being able to look back and see what worked and what didn't. Knowledge of severe vitamin deficiency diseases is an example of learning the hard way. The association of vitamin B1 (thiamine) with beriberi was perhaps the first example of the consequences of refining a food. Milling away the unattractive outer husk of the rice that contained the thiamine caused the disease. No drug could substitute for that missing, essential, "vital amine." That's how "vitamins" first got their name.
The Effect of Vitamin D on Cancer Incidence and Survival
The results of a phase 2 randomized controlled trial (RCT) of high- vs. low-dose vitamin D3 supplementation for 139 patients with advanced colorectal cancer taking chemotherapy was recently reported in JAMA