The health benefits of dark chocolate products have been widely reported and happily embraced for years. Cocoa's health perks come from botanical compounds called flavonoids — natural plant chemicals are found in many fruits, vegetables and spices. Flavonoids, have anti-inflammatory, antioxidant, antiviral, neuroprotective and cardioprotective properties.

It's been said that dark chocolate can help to reduce blood pressure, boost brain function and balance the microbiome in our gut.

Heavy metal exposure is particularly damaging to children's development, but it's cause for concern for everybody.

Unfortunately, it appears that eating too much dark chocolate and other cocoa products could be putting our health in danger, new research shows. A disturbing number of cocoa products contain heavy metals like lead, cadmium, mercury and arsenic. More surprising, they're particularly high in organic versions of chocolate.

Researchers at George Washington University came to this conclusion after analyzing 72 cocoa products commonly found on grocery shelves. They measured the contamination from heavy metals including lead, cadmium and arsenic in cocoa products every other year for the past eight years and. In high enough amounts, all these metals are toxic and hazardous to our health.

This year their analysis revealed:

  • 43 percent of the products studied exceeded the maximum allowable dose level for lead.
  • 35 percent of the products studied exceeded the maximum allowable dose level for cadmium.
  • None of the products exceeded the maximum allowable dose level for arsenic.
  • Products labeled as organic had higher levels of both lead and cadmium than non-organic versions.

So, what does this mean if you enjoy eating lots of chocolate? You need to take the same precautions you are likely taking when it comes to eating tuna. “We all love chocolate but it's important to indulge with moderation as with other foods that contain heavy metals including large fish like tuna and unwashed brown rice,” the study's lead author, Leigh Frame, director of integrative medicine and associate professor of clinical research and leadership at the GW School of Medicine and Health Sciences, said in a press release.

Many cocoa products labeled as organic had higher levels of both lead and cadmium than non-organic versions.

Heavy metal exposure is particularly damaging to children's development, but it's cause for concern for everybody. The Environmental Defense Fund lists the following as the key health concerns associated with exposure:

  • Lead. Impaired brain development and lower IQ's in children, cardiovascular disease and cancer.
  • Inorganic arsenic. Impaired cognitive development in children, cardiovascular disease.
  • Cadmium. Kidney disease, cardiovascular disease and cancer.

“While it's not practical to avoid heavy metals in your food entirely, you must be cautious of what you are eating and how much,” Frame advised. If you're concerned that you might have accumulated a harmful level of heavy metals in your body, you can ask your healthcare provider to run a heavy metals test and find out. These tests check for the presence of heavy metals using a blood, urine or hair sample.

Depending on your results, your doctor may decide you need treatment. He or she will lay out the next steps.

The study is published in Frontiers in Nutrition.