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.
CNN has reached out to Dr. Elazer Edelman, one of the study's authors, and is waiting to hear back.
People 40 or older should be especially vigilant about their black licorice consumption: even 2 ounces per day, over a two weeks 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 1 to 2 weeks, according to the study.
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.