People say it is healthy... I don't really see how though. You can also show people you care in better ways.
What it can do is help you understand your insecurities in order to deal with them better. However, jealousy doesn't do this on it's own. in fact, jealousy is the outcome of dealing with your insecurities poorly, it is a reflection of your insecurities. You can work backwards and figure out the real problem by recognizing it as a marker. Understanding your jealousy will help dissolve it.
As far as actions that show you care go, jealousy is probably on the lowest point of the scale anyway.
I think once in a while, a little jealousy is okay. Not necessarily a deal-breaker. Some people find going out of their way to get some jealousy out of their partner to actually help, to let them see that yes, their s/o still is all for them.
Jealousy is often seen as positive-reinforcement that yes, your partner still wants you. So as long as you don't let it go too far, like purposely flirting with other people right in front of your partner while even ignoring them, then it should be okay.
no amount of jealousy is good in a relationship. it just shows how much of an insecure attention whore the jealous person is. a little of many things is good in a relationship, jealousy is not one of them.
A little bit of the "I don't like that acquaintance of yours", meaning a girl you work with, or something of the like, can be nice, since it shows that the woman really likes you and wants you all for herself: that's sweet.
The case I do not like (it's a huge turn off, and probably the main reason why I left my girlfriend) is that where the girl will try to make YOU jealous talking about other guys. I find that like a stab in the back.
I think a little jealousy is good. I want my boyfriend (if I had one) to be a little jealous. Not to the point where he controls my life, but just a twinge of jealousy here and there. I think it's cute.