Since the end of June 2025, there has been a lot of news: dark chocolate can contain significant quantities of cadmium, a heavy metal classified as a definite carcinogen (IARC 1). UFC-Que Choisir’s survey shows that a single 20 g bar can contain up to ~9 µg of cadmium, a significant proportion of the tolerable intake, especially among children and heavy chocolate lovers.
Dark chocolate contains cadmium: why, and at what levels?
Cocoa naturally “pumps” cadmium from certain soils. In practice, the higher the cocoa content of chocolate, the higher the potential cadmium content. The European Union has framed these levels since Regulation (EU) No. 488/2014:
- < 30% cocoa (milk): ≤ 0.10 mg/kg,
- 30-50% cocoa: ≤ 0.30 mg/kg,
- ≥ 50% cocoa (dark): ≤ 0.80 mg/kg,
- cocoa powder sold to the consumer: ≤ 0.60 mg/kg.
Levels vary according to bean origin and soil geology: several studies show levels often higher in certain areas of Latin America (volcanic soils, acid alluvial sediments) than in West Africa. This is primarily due to terroir (pH, volcanism, sedimentation), not farming methods.
What do these figures mean for consumers?
EFSA has set a tolerable weekly intake (TWI) of 2.5 µg/kg body weight/week (≈ 0.35 µg/kg/day). Que Choisir’s analysis reminds us that a 20 g bar can represent a significant fraction of this ceiling – even approaching it for a child. In other words, even without exceeding legal thresholds, dark chocolate makes a significant contribution to total exposure.
A reminder of recent news: widespread contamination beyond chocolate
The alert did not come from nowhere. In early 2025, the TV program Zone Interdite (M6) revealed traces of cadmium in 41 out of 41 breads tested, pointing to phosphate fertilizers as a major source for cereals (bread, pasta). In June 2025, several groups of doctors spoke of a “health bomb”, calling for stricter limits on fertilizers and screening measures. European media reported these findings (bread, cereals, potatoes).
As for phosphate fertilizer regulations, the EU has set a limit of 60 mg Cd/kg P₂O₅ in 2022, with the prospect of a reduction to 20 mg/kg by 2034, in line with recommendations from ANSES.
Finally, biomonitoring programs (ESTEBAN) confirm widespread impregnation of the French population, with major determinants such as diet and smoking (a major non-food source).
To remember: dark chocolate is not the only contributor, but it adds to other dietary and environmental sources – hence the importance of acting on all levers rather than focusing on a single food.
Should we stop eating chocolate? No… but adopt some simple reflexes
- Moderate portions, especially for children and those who eat chocolate regularly.
- Vary origins and cocoa percentages (all things being equal, a 70-85% chocolate will often contain more cadmium than a 50-60% chocolate).
- Diversify sweets (not just dark chocolate, which is very rich in cocoa).
- Take care with mineral intake (iron, zinc, calcium) and stop smoking: certain nutrients and the absence of smoking limit Cd absorption and/or effects.
Why talk about “cleansing foods”: the role of fiber… and chlorella
Dietary fiber, a daily ally
Several studies (reviews, experimental studies) suggest that certain fibers (wheat bran, pectin, resistant starch, etc.) can trap cadmium in the intestine and limit its absorption, while protecting the microbiota from the deleterious effects of metals. Without transforming human physiology, a good “fiber base” helps reduce the bioavailability of part of the cadmium ingested. Priority should therefore be given to legumes, wholegrain cereals, fruit and vegetables, and functional fibers where necessary.
Chlorella: a natural “sensor” documented by research
Chlorella is a micro-algae rich in fiber, chlorophyll and antioxidants. Preclinical literature shows that it can reduce the absorption and tissue accumulation of cadmium and increase its fecal elimination, while attenuating inflammation/oxidation via Nrf2/NF-κB pathways. In vitro studies confirm its capacity for Cd biosorption. (Human data remain more limited and heterogeneous; chlorella chlorella is used as a supplement to a protective diet).
Usual use (indicative): 3-5 g/day in powder or tablets, to be integrated into a routine rich in fiber and hydration; choose quality chlorella (traceability, heavy metal controls).
Chlorella Bio Ultra Pure
FAQ express
Does the chocolate in stores comply with the law?
Yes, the vast majority complies with European limits; however, this does not prevent a significant contribution to cumulative exposure (depending on the proportion of chocolate in the diet, age, weight, etc.).
How can I reduce my exposure without giving up chocolate?
Alternate percentages and brands, limit frequency/serving size, and boost fiber (legumes, oat bran/wheat, fruit/vegetables). A chlorella supplement can complete this nutritional strategy.
Why are we talking so much about cadmium in 2025?
Because surveys and calls from doctors have highlighted widespread contamination (bread, cereals, potatoes, etc.), and called for tighter limits on fertilizers.
Should I stop eating chocolate?
Should we stop eating chocolate? No. But it’s better to put it back in its rightful place: as a measured pleasure, particularly for chocolates with a high cocoa content and for children. At the same time, boosting fiber and **adding natural “captors” such as chlorella will help limit the absorption and support the elimination of cadmium as part of an overall strategy: dietary diversity, informed choices, and vigilance with regard to other sources (cereals, tobacco, environment).