Earlier quoted context omitted.
If you have a study that shows higher all cause mortality please link it. My hypothesis would be that healthy people don't take vitamins because they never saw the need, putting already sick people in the second category. I doubt that taking vitamins can actually do much harm in low doses.
I just Googled "vitamins lead to higher all cause mortality." First result: https://www.sciencedaily.com/releases/2011/10/111010173019.h... >After adjustment, use of multivitamins, vitamin B6, folic acid, iron, magnesium, zinc and copper, were all associated with increased risk of death in the study population. The top three links showed association between beta carotene supplementation and risk of death. A little fu…
If you read that link you'll see the findings for iron and calcium were replicated. (Not to mention this article is basically referencing a different article which is somewhere else, so we're missing the context)
The B12 issue, as the own article mentions, is not necessarily connected to a dietary excess consumption
> Participants within the highest quartile of vitamin B12 plasma concentrations (>455.41 pg/mL) were more likely to be older and have higher BMI and blood pressure.