Chocolate contains cadmium that can increase cancer risk

Children and adults all over the world love chocolate, either enjoying it by eating chocolate bars or sipping warm cocoa drinks.

But behind its delicious taste, cacao contains cadmium, a chemical substance harmful to kidneys. It also increases the risk of cancer.

If we compare it to other harmful heavy metals like arsenic, cadmium may not seem to be that bad. But, exposure to cadmium for a long time, even in small amounts, can be dangerous as it accumulates in the body. Our body needs ten to thirty years to digest cadmium.

This is why the European Commission last year decreased the safety threshold of the amount of cadmium in processed chocolate in the region. The cadmium threshold is between 0.1 and 0.8 milligrams per kilogram of chocolate, depending on the type of chocolate.

Dark chocolate, for instance, has a lower ceiling than milk chocolate. All chocolate imported to Europe have to comply with the limit.

Europe’s decision was based on research that showed even though cadmium exposure in adult non-smokers in the region is still below WHO’s upper limit, exposure through food in children reaches twice the safe limit.

Meanwhile in Indonesia, the maximum limit on cadmium is 0.5 milligram per kilogram of chocolate and cacao product. The amount is roughly the same as the new European regulation for processed chocolate with over 30% cacao.

Cadmium levels

Chocolate is not the only food that contains cadmium. But because chocolate is often consumed by people of all ages, including children, its amount of cadmium must be regulated. This chemical is often associated with bone density problems.

Cadmium levels in processed chocolate on the market vary depending on the production process and the producers.

Generally, the cadmium rate in processed chocolate is minimal because of the mixing of raw chocolate with milk, sugar and syrup during production. The chocolate level in a product is between 10% (for milk chocolate) and 70-100% (for dark chocolate). However, if you eat too much chocolate for a long time, the cadmium amount in your body will increase.

A 2010 study on cadmium levels in chocolate powder from various countries showed chocolate powder from Venezuela was up to 1.8 milligrams per kilogram of powder. It’s higher than the European Commission standard.

Meanwhile, several studies on cadmium in processed chocolate in Brazil, the United States and India concluded the level of cadmium was under the safety limit.

Even in chocolate containing 100% chocolate, some processing has been carried out. Mixing cocoa beans from several sources, for example, can reduce the levels of cadmium in processed chocolate. The amount of cadmium content in cacao beans depends on the location and soil conditions where the chocolate plant is grown, as well as on the type of the chocolate plant itself.

WHO only has a limit on the amount of cadmium for dried cacao beans – 0.3 milligrams per kg. The maximum level of cadmium that can be tolerated by the human body, according to WHO, is 0.025 milligrams per kg of body mass. This is equivalent to 1.25 milligrams of cadmium for a person with a body weight of 50 kilograms per month.

By the WHO’s standard, it is potentially dangerous for a person who weighs 50 kilograms to consume more than 12.5 kilograms of 30% cocoa processed chocolate, that is under the European Commission’s ceiling, in a month; or to consume 2.5 kilograms of processed chocolate according to Indonesia’s ceiling.

Cadmium exposure

Exposure to excessive cadmium through food has a significant effect on kidney health, disrupting reabsorption (such as the reabsorption of protein salt the body still needs) in the kidney’s filtering unit.

Apart from food, cadmium exposure through air is known to increase cancer risk, causing shortness of breath, lung irritation and mucous membrane damage. Cadmium exposure through the air in daily life, for example, occurs through cigarette smoke.

In the 1960s, Japan experienced cadmium contamination in its water. A study of a decades-long strange illness in residents in Toyama Prefecture reveals “itai-itai” disease, caused by heavy metal pollution, especially cadmium, from mines in the upper reaches of the Jinzu River. Itai-itai disease is marked by bone softening, bone loss and kidney damage.

People with this disease complain of pain in the spine and joints due to reduced bone density associated with the toxic effects of cadmium. However, keep in mind this is an extreme case caused by chronically large amounts of cadmium poisoning.

Why does food contain cadmium

Plants can absorb and accumulate cadmium from water in the soil.

Chocolate plants can absorb cadmium through its roots and store it in chocolate leaves and seeds. This absorption can be influenced by soil acidity and the amount of cadmium available in the soil.

Therefore, geographical location can affect the cadmium content in plants. Volcanic soils, for instance, can contain higher amounts of cadmium. Environmental pollution and excessive use of fertilisers containing cadmium are also factors affecting cadmium levels in the soil.

In the case of itai-itai disease in Japan, cadmium in wastewater from mines flows and pollutes water sources used for irrigation by residents. Water pollution also pollutes aquatic ecosystems such as rivers and seas.

In addition to preventive action, remediation is one of the solutions to reduce levels of cadmium in the environment.

Reducing cadmium exposing

The easiest way to reduce the risk of cadmium exposure in everyday life is to avoid materials that have the potential to contain large amounts of it.

For example, you should limit consumption of chocolate, shellfish taken from contaminated waters and plants harvested from contaminated soil. You should stop smoking and keep away from secondhand smoke exposure to avoid cadmium through the air.

Environmental pollution causes a high amount of cadmium in various foods. Therefore, the most appropriate way to reduce cadmium exposure is to protect the environment from the potential for cadmium pollution.

Disposing of NiCd (nickel-cadmium) batteries properly, using fertilisers that contain cadmium at appropriate levels, and monitoring the content of cadmium in the environment around waste disposal are some examples of preventive measures that can reduce exposure to cadmium in the community.


This article authored by Mila Sari is republished from The Conversation under a Creative Commons license. Read the original article here. The views or opinions expressed by individuals do not necessarily reflect those of the University.

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