Licorice is a stickier subject than you might imagine. Strawberry and Cherry Twizzlers, for example, the oh-so-popular movie candies that everybody thinks of as licorice, don't contain licorice of any kind. And real licorice, which is derived from the root of a shrubby plant called Glycyrrhiza glabra, has been linked to an array of health problems.
Though it seems benign, licorice is a "good news and bad news kind of herb," says registered dietitian Roberta Anding of Texas Children's Hospital. For centuries, licorice has been used to treat a multitude of ailments, including stomach ulcers, bronchitis, sore throat and viral infections. A review of several clinical trials found that glycyrrhizic acid, a molecule found in licorice root, might actually reduce complications from hepatitis C in some patients. But the "trials were poorly designed," says Anding, and there isn't enough evidence to actually say that licorice can help with any medical problems.
But it might cause a few. According to the National Institutes of Health, licorice has been linked to salt and water retention and low potassium levels. It can also cause an increase in levels of cortisol, a hormone linked to high blood pressure. Some research suggests it may even cause preterm labor. To top it off, licorice may not be good for the libido. Hormonal imbalances have been reported with the use of licorice, such as abnormally low testosterone levels in men.
Most licorice candies (especially those in the U.S.) are flavored with anise oil (a spice with a licorice taste) or made with a licorice root extract called DGL (deglycyrrhizinated licorice root) that does not contain glycyrrhizic acid. DGL is not associated with many of the adverse effects of licorice. But if you satisfy your sweet tooth on occasion with some real-deal licorice candy available at import stores or online, don't panic. Levels of licorice root in a serving-size portion of candy are not as high as those found in herbal supplements. But don't binge on it, either. Limit yourself to a few pieces. And avoid it if you have high blood pressure or heart disease.
If you plan on buying a licorice root supplement at your local health food store, be smart and talk to your doctor. Once you get an OK, follow dosing guidelines, which may differ depending on the product you purchase. High doses of licorice root (50 grams or more per day) and taking it longer than two to six weeks, may cause high blood pressure, among other problems. "Licorice is an herb that should be taken very seriously," says Christine Gerbstadt, M.D., R.D., spokesperson for the American Dietetic Association. "Just because something is natural doesn't mean it's safe."
When it comes to Twizzlers, it's actually sugar that you need to think about. Only the black (licorice) version contains licorice extract, minus the acid. One serving of the licorice or strawberry flavor—four pieces—contains 20-21 grams of sugar. That's about five teaspoons of sugar per serving. Although you won't have any of the bad biological effects from licorice root, "you're going to have one heck of a sugar buzz if you eat the whole bag at the movies like most of us do," says Gerbstadt.