One of the 35 meta-analyses reviewed for the writing of this page commented on heavy metals. The authors read through the 31 randomized controlled trials that they included in the meta-analysis, but none of the studies mentioned the risk of contamination with heavy metals.[1]
In individual studies of heavy metals in chocolate, studies in the United States,[2], Europe,[3], Poland,[4] Iran,[5] Bangladesh,[6] and India[7] have found heavy metals at acceptable levels. Furthermore, studies in countries such as Ghana and Brazil (major sources of global cocoa production) have found that heavy metals in cocoa are within the acceptable limits.[8][9][10][11]
However, a few studies have reported elevated levels of cadmium or lead in cocoa products. For example, in Ecuador (a common producer of cocoa), 12 of 19 production sites were found to have cocoa with cadmium levels that exceeded the acceptable levels.[12]. In Japan, 4% of the chocolate products and 19% of the cocoa powder products that were tested in one study had cadmium (but not lead) levels that were higher than the guideline levels.[13][1] Furthermore, a 2024 study in the United States reported a higher prevalence of high heavy metal levels in cocoa products; 35%, and 43% of cocoa products exceeded the guideline levels of cadmium and lead, respectively. The researchers noted that consuming more than one serving per day of these cocoa products, or a combination of other sources of heavy metals (e.g., seafood), may add up to amounts that are higher than the guideline levels.[14]
In other words, a majority of the studies that have examined the heavy metal content of chocolate from a variety of countries have found acceptable levels. Furthermore, in the studies that reported high levels of heavy metals in cocoa products, the researchers only found this to be the case in a minority of the products.