Late nights and early mornings can keep us from getting the sleep we need to make it through the day. For many, caffeine can help us out with that, whether it's a boost from a morning cup of coffee or a mug of steeped tea. But there's so much more to caffeine than just the classic cup of Joe — it's hidden in some unexpected places, like a scoop of ice cream and a box of mints.

The Mayo Clinic recommends limiting daily caffeine consumption to 500 milligrams (mg), while the American Academy of Pediatrics recommends adolescents limit their caffeine intake to 100 mg a day. Overloading on caffeine can lead to adverse effects, such as insomnia, nervousness, restlessness, irritability, stomach upset, fast heartbeat, and muscle tremors. So it's important to know how much you're getting, and from where.

Click on "slideshow" to see caffeine content, ranked from the lowest to highest concentrations.

Caffeine Concentrations
Beyond coffee, there are plenty of caffeine sources. Photo courtesy of Flickr, Barn Images