• Posted July 31, 2024

Are There Heavy Metals in Your Chocolate?

Toxic heavy metals are found naturally worldwide in soils that produce the cocoa bean tree -- and those metals are showing up in chocolate, a new report warns.

“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,” explained lead author Leigh Frame.

“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," added Frame, who directs integrative medicine at the George Washington School of Medicine and Health Sciences in Washington, D.C.

So-called "heavy" metals, such as lead, cadmium and arsenic, can be significant threat to health if consumed in sufficient amounts.

In their new study, Frame's team tested 72 cocoa-based products, including dark chocolate, for the presence of those metals. Products were tested every other year over eight years.

Among their findings:

• 43% of the products studied topped the maximum allowable dose level for lead.

• 35% studied exceeded the highest allowable dose level for cadmium.

• None of the products exceeded the maximum allowable dose level for arsenic.

Thinking of a switch to organic chocolate and cocoa to protect yourself? 

Think again: Products labeled organic actually had higher levels of both lead and cadmium compared to non-organic products, the Washington team found.

Frame and co-lead author Jacob Hands, a medical student researcher in the university's Frame-Corr Lab, say that snacking on a one-ounce serving of chocolate per day probably won't pose any harm. 

But eating multiple servings per day, or combining chocolate with other foods throughout the day that might also contain high heavy metal levels, could pose a health threat.

Foods that are imported from countries with lax regulation around soil contaminants such as heavy metals --- such as China, Nigeria, India and Egypt -- may also contain high levels, the researchers warned. 

Organ meats and foods or herbal supplements are products to be wary of in this regard, they said, as are shellfish. 

When it comes to cadmium, some foods to look out for are seaweeds, especially Hijiki seaweed, Frame and Hands said.

The authors noted that there's been evidence that a bit of dark chocolate might have real health benefits to the brain, heart and in reducing inflammation. But they added that the possible deleterious effects of heavy metal in dark chocolate haven't been taken into account.

The new study was published July 31 in Frontiers in Medicine.

More information

Find out more about the health benefits of chocolate at the American Heart Association.

SOURCE: George Washington University, news release, July 31, 2024