“The greatest tragedies were written by the Greeks and Shakespeare ... neither knew chocolate,” says Sandra Boynton, the author of the beloved birthday card “Hippo Birdie Two Ewes” and more than 50 children’s books.

Is that another reason Americans are feeling blue? Could be. The kind of chocolate you and your neighbors eat is often super-processed milk and white chocolates, which are stripped of many of the magic bean’s benefits — that’s about as bad as (or worse than) having no chocolate at all!

Instead, enjoy 70 percent cacao dark chocolate. It’s loaded with cocoa solids that contain health-boosting compounds like flavonoids. Enjoy hot chocolate made with walnut or almond milk (make sure they don’t contain the emulsifier carrageenan) and natural, unsweetened cocoa powder. It contains more flavonols (a type of flavonoid) than cocoa powder that’s Dutch-processed or alkalized.

Research shows that chocolate helps control blood pressure, fights cancer and neurodegenerative diseases, and improves athletic performance. But despite headlines declaring chocolate is more effective than cough medicine, the researcher who published the study that gave rise to that claim makes it clear in an article on Health.com that the tested cough syrup, which contained the cocoa-based compound theobromine and antihistamine diphenhydramine, isn’t the same as a chocolate candy or drink.

So enjoy a daily ounce of dark chocolate for its health boost and flavor, and see your doc to treat a dry or wet cough.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is chief wellness officer and chairman of Wellness Institute at Cleveland Clinic.