It seems like simple, obvious advice: Eat your vegetables, get some exercise, and - of course - take your vitamins.

Or not.

Decades of research has failed to find any substantial evidence that vitamins and supplements do any significant good. In fact, recent studies skew in the opposite direction, having found that certain vitamins may be bad for you. Several have been linked with an increase in certain cancers, for example, while others have been tied to a rise in the risk of kidney stones.

And a large new study out last week suggests that despite this growing knowledge, pill-popping habits have stayed basically the same over the last decade.

So here are the vitamins and supplements you should take — and the ones you should avoid:

Multivitamins: Skip them — you get everything you need with a balanced diet.