Washington: Dark chocolate may offer antioxidants and other nutritional benefits, but investigations have found that some widely sold products also contain concerning amounts of lead and cadmium.
Consumer Reports tested 28 dark chocolate bars and detected both metals in every product. In 23 bars, a one ounce serving contained enough lead, cadmium, or both to exceed California’s maximum allowable daily dose levels.
These thresholds are stricter than many other regulatory benchmarks. Crossing them does not prove that eating one serving will cause illness, but it indicates a potential concern when chocolate is consumed regularly or alongside other sources of heavy metals.
A separate study published in Frontiers in Nutrition examined 72 cocoa products purchased in the United States in 2014, 2016, 2019 and 2022.
Researchers found that 43 per cent exceeded California’s limit for lead and 35 per cent exceeded its cadmium limit. None exceeded the threshold for arsenic. Organic products generally contained higher levels of lead and cadmium than conventional products.
Cadmium can enter cacao plants through contaminated soil and accumulate in the beans. Lead contamination is more likely to occur after harvesting when beans are dried, transported or processed in environments containing contaminated soil or dust.
Health risks depend on the amount consumed, the frequency of exposure and exposure from other foods and environmental sources. Long term exposure to lead can harm the nervous system and is especially concerning for children and pregnant women. Cadmium can damage the kidneys and affect bones and other organs over time.
The findings do not require consumers to abandon dark chocolate entirely. Researchers advise moderation, dietary variety and avoiding large daily servings. Parents may exercise greater caution when giving dark chocolate to young children.
Tests also found substantial differences among products, showing that manufacturers can reduce contamination through careful sourcing, improved soil management and cleaner processing. However, a favourable result for one product batch does not guarantee that every later batch will contain the same levels.
The larger issue is therefore not chocolate alone. It is the need for regular testing, transparent standards and manufacturing practices that reduce preventable exposure while allowing consumers to make informed choices.
