Dark chocolate is packed full of flavonoids, antioxidants that promote heart health and lower blood pressure. In moderation, it's a healthy treat but dark chocolate contains other ingredients such as milk and sugar, and possibly less appetizing components including toxic pesticides. If you are a chocoholic, you may wonder how frequently these toxins are found and how dangerous they are.
Lindane
In 1998, a survey of chocolate by the UK Chemicals Regulation Directorate found trace amounts of gamma-hexachlorocyclohexane, a pesticide more commonly known as lindane. The U.S. Environmental Protection Agency banned lindane as a pesticide in 2006 due to its proven toxic effects on the nervous system, and suspected effects on liver, kidney and endocrine function. Lindane is persistent and bio-accumulates, so chronic exposure to small doses can lead to toxic buildup in the body.
Pirimiphos-Methyl
The UK Chemicals Regulation Directorate found an organophosphus pesticide called pirimiphos-methyl in approximately 5 percent of the chocolate samples tested in the first quarter of 2007. The EPA reports pirimiphos-methyl overstimulates the nervous system causing nausea, dizziness at confusion. They also report the chemical can cause respiratory paralysis and death, but only at very high doses such as might be experienced in a major pesticide spill. The EPA considers pirimiphos-methyl safe at the levels encountered in a normal diet.
Endosulfan
The 2007 UK chocolate survey also detected traces of an organochlorine called endosulfan. The EPA warns endosulfan has high toxicity when ingested and, like pirimiphos-methyl, overstimulates the nervous system. They have expressed concern about potential toxicity levels from food in children under the age of six, but they specifically pointed to crops such as succulent beans and peas. They list no specific concerns with use of the pesticide on cacao plants.
Theobromine
Dark chocolate has a higher level of cocoa powder than other forms of chocolate, and cocoa contains a substance called theobromine. Although non-toxic to humans, this chemical is extremely toxic to dogs, cats and other pets. According to the Mar Vista Animal Medical Center, a 10-lb. pet needs to eat less than 1.5 oz. of dark chocolate to ingest toxic levels of theobromine. Theobromine poisoning symptoms include vomiting, seizures and death. Theobromine occurs naturally in cacao beans and cannot be removed. Save your chocolate for yourself, and keep it well out of reach of your pets.
Dark Chocolate Safety
The amounts of pesticides found in chocolate are quite small, however, some chemicals such as lindane build up in the tissues and could prove toxic over years of accumulation. Lindane is no longer used in the United States but many other countries still use the pesticide. If you are concerned about the possibility of poisonous compounds in dark chocolate, buy organic chocolate. You'll pay more, but you can rest assured that the no pesticides were used when growing the cacao beans.
References
- Chemicals Regulation Directorate: Residues found in retail samples of CONTINENTAL CHOCOLATE in 1998
- U.S. Environmental Protection Agency: Lindane Voluntary Cancellation and RED Addendum Fact Sheet
- Chemicals Regulation Directorate: Pesticide Residues Monitoring Report; September 2007
- U.S. Environmental Protection Agency: Pirimiphos-Methyl IRED Facts
- U.S. Environmental Protection Agency: Endosulfan RED Facts
- Mar Vista Animal Medical Center: Chocolate Toxicity
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