Halloween is the biggest candy eating holiday in the US, and many Americans will be stashing up on licorice: but in a timely update to consumers issued this week, the Food and Drug Administration asks: do you realize that you can overdose on licorice? Eating too much (for instance 2 ounces a day for two weeks), especially if you are aged 40 or older, can land you in hospital with irregular heart rhythm (arrhythmia). The FDA advice is, no matter what your age, don’t eat too much licorice.

The problem is that too much licorice can cause your potassium levels to drop, say FDA experts. And that is bad news, because potassium is an essential electrolyte that is involved in electrical and cellular activity throughout the body. Without it, we would seize up like robots when their batteries run out. Here are just some examples of what it plays a key role in:

  • Balancing acids and bases in body fluids.
  • Making proteins from amino acids.
  • Metabolizing carbohydrates to make energy.
  • Building muscle and growing tissue.
  • Keeping electrical activity in the heart normal.

Black licorice contains glycyrrhizin, a sweet compound found in the root of the licorice or liquorice plant, a low-growing shrub mostly grown for commercial use in Greece, Turkey, and Asia.

It’s the glycyrrhizin that causes the drop in potassium in the body, causing some people to experience abnormal heart rhythms, as well as high blood pressure, edema (swelling), lethargy, and congestive heart failure.

Dr Linda Katz, of the FDA’s Center for Food Safety & Applied Nutrition, says when you stop eating the licorice your potassium levels should go back to normal with no permanent health problems.

Last year the FDA received a report of a black licorice lover who experienced some problems after eating it.

Also, several medical papers have linked black licorice with health problems in the over-40s. Some of those affected had high blood pressure and/or a history of heart disease.

Licorice has long been a folk or traditional remedy in both the East and the West for heartburn, bronchitis, sore throat, cough, heartburn, and some viral infections such as hepatitis, but the National Institutes of Health (NIH) say there is little scientific evidence to show it is effective for any medical condition.

Many licorice or licorice flavor products sold in the US actually contain no licorice, says the FDA. These usually contain anise oil which tastes and smells the same.

According to the NIH, you can also buy licorice root as a supplement without the glycyrrhizin: the product is known as deglycyrrhizinated licorice, or DGL.

If you really love black licorice, the FDA suggests:

  • Regardless of your age, don’t eat a lot at one time.
  • If you have been eating a lot of it and have irregular heart rhythm or muscle weakness, stop eating it at once and see your doctor.
  • Black licorice can interfere with the action of medications, herbs and dietary supplements. If you take any of these, ask your doctor about possible interactions.
  • If you have any problems after eating licorice, get in touch with your nearest FDA consumer complaint coordinator (click here to find one).

So enjoy your Halloween and go easy on the candy, especially the licorice!

Written by Catharine Paddock PhD