The advice I have had is quite different around the B12 and the calcium, women in particular are vulnerable to calcium deficiency and when you realise that its too late, its all tied up with hormones, leading to bone problems.
The B12 also causes a crisis if you don't keep it topped up, and on here you'll find plenty of folk who have not had the jabs and have then found themselves having to have loading doses of injections every day for a couple of weeks.
Personally I am glad that I am on both of them prevention better that a cure in my opinion!!!