This is very much a "side note," but a few things Mrs. D mentioned is so familiar; its almost uncanncy.
My doctor put me on 5 mgs. of B12 and my energy level is MUCH better. Nothing was working previously. He indicated that he might lower it at some future time.
In addition, I had relatives on my husband's side who loved candy. They particularly loved Easter Candy. This couple lived to be elderly. The husband was close to 100 when he passed away.

I have a friend who swears that Centrum Silver is an excellent overall multi vitamin for folks over 50. You could start there, add B12 and possibly Co-Q10. I don't know about other parts of the world, ,but in the US I have seen Vitamins, (including Co-Q10) go "on special" at various drug stores. Sometimes you can buy this product "buy one get one free." When I see specials like this, I always buy several. At one particularly drug store, I have often seen a sale "Buy one, get the second one 1/2 price." I always buy at least a few when I see this particular "deal." If you are interested in purchasing Co-Q10, I think it really pays to watch for the advertisements and stock up.