www.nature.com/articles/s41430-020-0558-y.pdf
There is controversy about Vitamin D supplements. At least there should be routine testing for deficiency covered by health insurance which it is not. With 7.4 % of Canadians reporting deficiency it is a public health issue.
Prevalence rates of severe vitamin D deficiency, defined as 25(OH)D <30 nmol/L (or 12 ng/ml), of 5.9% (US) [18], 7.4% (Canada) [19], and 13% (Europe) [2] have been reported. Estimates of the prevalence of 25(OH)D levels <50 nmol/L (or 20 ng/ml) have been reported as 24% (US), 37% (Canada), and 40% (Europe). T