Like the antibacterial soap and the fruit, vitamins do raise health, but sometimes it doesn't make enough of a difference to be visible. Also, if they're actually sick, it doesn't seem to help; you have to heal them first. I have mostly only seen a difference with peeps who were neither sick nor weak. They just had a little bit missing off their health bar, and the vitamins helped fill it back up.

I just give them to pregnant peeps because it's realistic. LOL