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 Wednesday suggests that despite this growing knowledge, Americans' 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:

For decades, it was assumed that multivitamins were critical to overall health. Vitamin C to "boost your immune system," Vitamin A to protect your vision, Vitamin B to keep you energized.

Not only do you already get these ingredients from the food you eat, but studies suggest that consuming them in excess can actually cause harm. A large 2011 study of close to 39,000 older women over 25 years found that women who took them in the long term actually had a higher overall risk of death than those who did not.

Business Insider