Mayans concocted a bitter, frothy, hot brew from roasted cocoa bean paste, chili peppers and cornmeal.

Later the Aztecs adopted the custom, but sipped what they called Chocolatl at room temperature; Montezuma is said to have downed 50 cups a day.

Mayans and Aztecs revered the cocoa bean's flavor and even used it as currency. They didn't suspect that its true powers were displayed in their guts.

A new study reveals that the magic bean acts as a PRE-biotic; its nondigestible components, including fiber, encourage growth of beneficial PRO-biotics, such as bifidobacterium and lactobacillus.

As these good gut bacteria feast on the chocolate, they ferment it, producing compounds that help tamp down potentially harmful bacteria like E. coli, ease inflammation, promote heart health and aid digestion (preventing Montezuma's revenge, perhaps!). That happy tango helps keep your immune system balanced.

But hold off on chocolate syrups and candy bars! They're loaded with added sugar and not much chocolate goodness.

We recommend you enjoy 1/2 ounce of 70 percent dark chocolate, no less than a couple times a week and no more than once a day. One-half ounce delivers 85 calories and 6 grams of fat - 3.5 of them a saturated fat that your liver wonderfully converts to a healthy fat on its first pass through.

Our favorite ways to use that half-ounce: added to a spicy tomato sauce over grilled chicken; grated into black beans with a dash of cinnamon; or melted into a cup of coffee for an after-dinner treat.

© 2014 Michael Roizen, M.D. and Mehmet Oz, M.D.
Distributed by King Features Syndicate, Inc.