Which Vitamin Supplement Has Metallic Smell?

Hi...my husband had bypass last oct...has had no problems , has lost a lot of weight, he is plum skinny... His chest and shoulders are just boney....but the question I have is...he has always taken his vitamins....but these last few months I don t like to kiss him because of a weird smell, I mean even if he breathes out his nose, I still smell it....it is really aggravating, because I love to kiss him, it s got to be a vitamin, but we don t know which one, we are hating this, he said maybe he s kinda like a metallic smell......oh yes and one more thing, he has the most horrible gas,,,some times he has to sleep in the other room, hope you can help..thank you