Cadmium In Chocolate: Everything You Need To Know

Those who love chocolate consider it a perfect food.

Rich in nutrients and poor in side effects, chocolate has been recently liberated from years of bad reputation. It doesn't cause acne anymore, or contribute to weight gain. Actually, we hear so often about its health benefits that we feel encouraged to eat more of it, without any sense of guilt.

The only negative sides of chocolate mentioned by the media regards socio-economic matters, like child labour and the poverty level of cacao farmers. But there is another discussion going on under the radar that is concerning a growing number of chocolate lovers. A metal intruder is threatening the restored popularity of chocolate.

The buzz killer is called Cadmium.

Craft chocolate makers are powerless when it comes to cadmium in their chocolate.
PHOTO CREDIT: The Food Pornographer.

Cadmium is a heavy metal considered toxic for the human body. When ingested or inhaled, it is not well absorbed by the body, so it accumulates over time and can have detrimental effects on kidneys, lungs and bones. This is why it is classified as a human carcinogen and can potentially increase the risks of cancer.

Although much concern surrounds its consumption, chocolate is not among the foods with the highest contamination of cadmium. As the European Commission highlights:

"The food groups that contribute most of the dietary cadmium exposure are cereals and cereal products, vegetables, nuts and pulses, starchy roots or potatoes, and meat and meat products. Also tobacco smoking can contribute to a similar internal exposure as that from the diet."

But since the global chocolate market is worth $100 billion, it is worth looking at how cadmium ends up in chocolate and what can be done to limit its presence.

The first big misconception to debunk about cadmium in chocolate is its origin.

Why is cadmium found in chocolate?

Unfortunately, cadmium can't be "taken out" of chocolate or completely avoided. It is not even the result of industrial processes or questionable manufacturing decisions. No fingers can be pointed at someone in the cacao supply chain for the presence of cadmium in chocolate. Because before any farming practice or chocolate making process, cadmium is already there. Not in the beans, not inside the tree, but in the soil.

Cadmium is naturally found in soil as a result of volcanic activity, forest fires and weathering of rocks. It is then taken up by many plants, like the cacao tree. The amount of heavy metal that ends up in the cacao beans depends on multiple factors. Among all the variables, geographic location and soil acidity are the ones playing the most relevant roles in the exposure of the soil to cadmium. Other factors like cacao variety seem to have less relevancy in this matter.

Despite being considered the world's prime supplier of fine cacao, cocoa beans from Latin America are particularly affected by cadmium contamination. Due to higher volcanic activities, traces of cadmium are more prominent in cacao from Latin America than from West Africa.

In October 2016, the team at ETH Zurich released the results of an extensive research conducted in Honduras and Bolivia to determine the causes of cadmium contamination at origin. The researchers found significant amounts of cadmium in the soils and beans of some remote hilly regions well away from polluting industry and intensive farming. Most plantations were only managed as agroforestry estates with minimum use of artificial fertilizers or pesticides, both of which can be sources of cadmium pollution.

Cadmium is found in the soil where cacao trees grow.

“We have no concrete proof that the problem is man-made. The cadmium seems to stem almost exclusively from the parent bedrock.” - confirms Dr Gramlich.

It is also still unclear whether the cacao variety has anything to do with the cadmium level in the chocolate. Do specific cacao varieties take up cadmium in their beans more easily than others? Some researchers believe that the more productive clones might be higher accumulators of cadmium, but that's really not sure yet.

The only certainty seems to be the correlation between cadmium and soil acidity. A higher acidity level in the soil usually corresponds to a higher level of cadmium accumulation. This is why one of the solutions proposed to resolve the problem is to add lime or zinc to the soil. These additions elevate pH and lower acidity.

Another precaution, suggested by the ETC Zurich team, is to check the cadmium content of the soil before planting any cocoa tree. If the levels are too high, another cash crop such as coffee could be grown instead.

Unfortunately, organic farming is not listed among the solutions, as it doesn't seem to help with the cadmium issue.

If some actions can be taken by cacao farmers, there is really nothing a chocolate maker can do to lower the cadmium in the cocoa beans he/she receives.

The high temperatures reached during roasting won't get rid of the cadmium in the chocolate. The only precaution a chocolate maker can take is to enhance the traceability of its sources and make sure that its cacao suppliers are taking action to deal with the problem at origin.

Better luck seems to find industrial chocolate manufacturers. They are able to keep down the cadmium content in their products thanks to purchasing in high volume and from different regions. Nonetheless, they are facing legal problems for the heavy metal content in their chocolate. Mars, Hershey and other chocolate manufacturers have received legal notices in 2015 from the non-profit organization As You Sow that accused them of exceeding safety standards for the state of California. The accusations seem to lack the fundamental understanding that cadmium is a naturally-occurring problem.

The latest news in the legal department is the introduction by the European Union of new limits on the amount of cadmium in cocoa products. They will be enforced starting 1 January 2019.

It's clear that little can be done to prevent cadmium in chocolate or completely eradicate the problem in the short term. For consumers, it is not fun to know that one of their favorite foods might contain heavy metals. However, cadmium in chocolate should not represent a great concern.

As mentioned above, there are other foods consumed daily and in larger quantities that are more affected by cadmium contamination than chocolate. Chocolate consumption that is limited to moderate quantities does not represent a danger for the human body. The side effects of cadmium can also be contrasted by maintaining sufficient levels of iron, calcium and zinc.