As we all know, chocolate is a popular treat around the holidays (well, pretty much year-round). However, a new report found that dark chocolate in particular…has a dark side.

According to Consumer Reports, researchers found that some dark chocolate bars contain cadmium and lead – two heavy metals linked to health problems.

CR scientists recently measured the amount of heavy metals in 28 dark chocolate bars and detected cadmium and lead in all of them, the consumer advocacy nonprofit said.

Cadmium and lead exposure are known to affect brain development and cause other developmental problems, making them especially dangerous to children and pregnant women, according to CR food researcher Tunde Akinleye.

“But there are risks for people of any age,” he says.

Consumer Reports says dark chocolate tends to have higher levels of heavy metals than milk chocolate because its higher cacao content.

Chocolate bars that tested high for both lead and cadmium:

  • Theo Organic Pure Dark 70% Cacao
  • Theo Organic Extra Dark 85% Cacao
  • Trader Joe’s The Dark Chocolate Lover’s 85% Cacao
  • Lily’s Extremely Dark Chocolate 85% Cacao
  • Green & Black’s Organic Dark Chocolate 70% Cacao

Chocolate bars that tested high for lead:

  • Tony’s Chocolonely Dark Chocolate 70% Cacao
  • Lily’s Extra Dark Chocolate 70% Cacao
  • Godiva Signature Dark Chocolate 72% Cacao
  • Chocolove Strong Dark Chocolate 70% Cacao
  • Lindt Excellence Dark Chocolate 85% Cacao
  • Endangered Species Bold + Silky Dark Chocolate 72% Cacao
  • Trader Joe’s Dark Chocolate 72% Cacao
  • Hu Organic Simple Dark Chocolate 70% Cacao
  • Chocolove Extreme Dark Chocolate 88% Cacao

Chocolate bars that tested high for cadmium:

  • Beyond Good Organic Pure Dark Chocolate 70% Cacao
  • Beyond Good Organic Pure Dark Chocolate 80% Cacao
  • Equal Exchange Organic Extra Dark Chocolate 80% Cacao
  • Lindt Excellence Dark Chocolate 70% Cacao
  • Scharffen Berger Extra Dark Chocolate 82% Cacao
  • Alter Eco Organic Dark Chocolate Classic Blackout 85% Cacao
  • Pascha Organic Very Dark Dark Chocolate 85% Cacao
  • Dove Promises Deeper Dark Chocolate 70% Cacao

Consumer Reports listed these chocolates as the “safest choices:”

  • Mast Organic Dark Chocolate 80% Cacao
  • Taza Chocolate Organic Deliciously Dark Chocolate 70% Cacao
  • Ghirardelli Intense Dark Chocolate 86% Cacao
  • Ghirardelli Intense Dark Chocolate Twilight Delight 72% Cacao
  • Valrhona Abinao Dark Chocolate 85% Cacao

But should you cut dark chocolate from your diet entirely? Not necessarily.

While the chocolate bars tested positive for concerning levels of lead, cadmium or both, Akinleye says levels were relatively low in five of the bars.

Dr. Michael J. DiBartolomeis, a toxicologist and former official at the California Department of Public Health, told Consumer Reports that chocolate makers should do more to ensure their cacao beans are harvested from areas with lower levels of heavy metals.