If you think you've made a good nutrition choice when you select a salad remember this. All greens are good, but not all greens are as nutritious as you may think.

The folks at eatthis.com put together a list of the worst greens for your health and here are some examples of them.

Iceberg Lettuce. It's been getting bad press for a while, and with pretty good reason. Iceberg Lettuce has almost none of the "key vitamins and minerals".

Arugula. Surprised? It's used in so many salads but it doesn't offer much when it comes to those key vitamins and minerals.

Dandelion greens. If you like them, experts say you may want to substitute beet greens if you want twice as much magnesium and potassium.