I have no idea! Does she shower every day, have good hygiene? All the things you listed could be the problem or all of them combined plus other things could be too. If she has been smelling like this for a while, she probably doesn't even know that she smells like this. Normally if you smell a certain way constantly, you can't smell it.

It might be that her pH is off balance. Or she could have halitosis (dental caused bad breath). She could also have a problem with her internal organs, like her kidneys, or it could be a really bad case of a yeast infection.

It would probably be a good idea to mention this to her, as she probably doesn't know...and probably would like to know for social reasons....and also because if she does have a condition, it is important that it is treated, especially since it could be something like kidney or liver disease and life-threatening.