The UK Consumer Association magazine, Which?, takes a very negative view on the efficacy of vitamins and supplements. Vitamin D is the sole exception.
I found some staggering claims through an hour or so of Googling but the highly authoritative website webmd.com provides the most promising study of all:
What brought the simmering debate to a boil was a 2007 study showing that people taking normal vitamin D supplements were 7% less likely to die than those who didn't take the daily supplements.
https://www.webmd.com/osteoporosis/features/the-truth-about-vitamin-d