(CNN) It's hard to exercise restraint when eating candy. For licorice lovers, indulging sparingly could actually be lifesaving.
A study published Wednesday in The New England Journal of Medicine says a 54-year-old man died as a result of eating too much licorice.
The man, a construction worker from Massachusetts, lost consciousness inside a fast-food restaurant and was taken to a hospital, where he died the next day.
Doctors wrote that he had "a poor diet, consisting primarily of several packages of candy daily," and that three weeks before, he switched from eating fruit-flavored soft candy to licorice candy, which contained glycyrrhizic acid.
Glycyrrhizic acid, or glycyrrhizin, a sweetening compound derived from licorice root, can cause a drop in potassium levels in the body, which in turn may cause high blood pressure, swelling, abnormal heart rhythms and even heart failure, according to the FDA.
"While black licorice is safe in small quantities, it can be dangerous when consumed in large amounts or even in more moderate amounts on a regular basis," Dr. Jacqueline Boykin Henson told CNN. She cared for the subject of the study as an internal medicine resident physician at Massachusetts General Hospital, and is now a gastroenterology fellow at Duke University.
The patient was not suffering from underlying conditions that would have had an impact on what happened to him, Dr. Boykin Henson noted.
"While his diet consisted largely of black licorice, he was active and otherwise generally healthy," she said, adding that the case has been reported to the FDA for further investigation on the safety of licorice.
People 40 or older should be especially vigilant about their black licorice consumption: even 2 ounces per day, over a two-week period, could cause irregular heart rhythm and may require hospitalization, the FDA cautions.
The negative effects of eating too much licorice are reversible, and wane when consumption is interrupted. A return to normal potassium levels may take one to two weeks, and some of the hormonal imbalances and effects on blood pressure can take months to normalize, Dr. Boykin Henson explained.
"Individuals who enjoy black licorice should be cognizant of these potential health effects and should be conscious of the amount they are eating and how often," Dr. Boykin Henson said.
"If they experience any symptoms concerning for electrolyte abnormalities such as muscle weakness or abnormal heart rhythms, they should stop taking black licorice. Individuals who already have either of these problems should probably avoid consuming black licorice," she advised.
Luckily, there are safe alternatives. According to the NIH, many licorice products available in the US don't actually contain licorice, but rather anise oil, which is comparable in flavor.