CHICAGO (AP) -- A new Centers for Disease Control and Prevention study has added to the relatively scarce information about how much salt American kids eat -- and it's too much.

The study finds they eat as much salt as adults -- about 1,000 milligrams more than they should. A thousand milligrams is about one Big Mac.

The recommended daily salt or sodium intake for kids and adults is no more than 1 teaspoon daily, or about 2,300 milligrams. On average, the study finds kids eat 3,300 milligrams daily.

Fifteen percent of the kids studied had either high blood pressure or slightly elevated blood pressure.

Those who ate the most salt faced double the risk of elevated blood pressure, compared with those who ate few salty foods. But among overweight or obese kids, the risk is more than triple.

The findings are online in the journal Pediatrics.