Did you run through your Valentine’s Day chocolates already? Or are they so special that you’re planning to savor them over the next week or two? Maybe you’re ambivalent about your chocolates– you love them, and yet, you have to wonder “how much lead am I willing to consume?”
Do your chocolates contain lead?
There are two ways to approach that question. The first is denial: “Not my chocolates! They’re too expensive!” The second involves steadfast scientific inquiry: “Hmm, what kind of studies have been done on this subject?” To be thorough, let’s take both approaches. Enjoy your chocolates while we search for answers.
Where did your chocolates originate?
Good luck figuring that out! Chocolate is unique because its raw materials –the cocoa beans–are produced in one part of the world while its final product–cocoa powder or chocolate–is manufactured and consumed in an entirely different part of the world. 
In other words, it’s hard to “eat local” when it comes to chocolate. To begin with, you’d have to live along the “20th parallel,” a region that circles the globe just above and below the equator. It’s the only place cocoa trees will grow. Cocoa trees need even temperatures, year-round precipitation, and midges for pollination. (Midges are small flying insects that resemble mosquitoes.) Aside from the midges, the 20th parallel sounds like paradise. Hawaii, for example, has what it takes to grow cocoa. Yet, given the cheaper labor, the majority of the chocolate we eat comes from cocoa beans grown on small farms in Africa, mostly along the Ivory Coast, or small farms in Indonesia, Brazil, or some other Latin American country.
Once the cocoa beans leave the farm, they head north to be made into chocolate. Since the melting point of chocolate is 97 degrees Fahrenheit (just below body temperature), it’s a lot cheaper and easier to manufacture chocolate in northern regions, where the climate is cooler. Most chocolate is manufactured and consumed in Europe and the United States.
In an article on the multinational histories of chocolate, Julie Cidell and Heike Alberts describe the chocolate supply chain as having a “double disconnect.” The people who grow the cocoa beans, small farmers in developing nations, rarely consume the final product of their work. Chocolate consumers—those of us in the wealthier, developed nations–have little way of tracing back the origins of our chocolate to a particular country, let alone a particular farm.
While the origin of our chocolate may be murky, one thing seems pretty clear: the chocolate you are eating probably contains some amount of lead.
The lead contents of chocolate and the products it flavors are among the highest of all commonly consumed substances.”
William I. Manton, in the Journal of Agriculture and Food Chemistry. January 27, 2010
According to William Manton, a professor who specializes in tracing lead in our environment, lead may get into chocolates at one or more stages of the chocolate-making process. The cocoa tree may absorb lead from the soil and transfer it to the beans. If a particular cocoa producing country still uses leaded gasoline, lead from vehicle exhaust may settle on the beans while they are out in the sun, drying by the roadside. Lead contamination may also occur while the beans are being stored, transported, or made into chocolate.
A study in Nigeria supports the idea that natural growing conditions are not the culprit when it comes to lead in chocolate. Scientists found relatively small amounts of lead in cocoa beans taken from six different farms in a major cocoa producing region of Nigeria. Whereas high amounts of lead were found in manufactured chocolate products.
Where do your particular chocolates stand?
It depends. Do you like milk chocolate or dark chocolate?
If you like milk chocolate, you’re in luck. Since children are avid consumers of milk chocolate, the FDA periodically screens milk chocolate candy bars for lead. As part of the FDA’s Total Diet Study, the candy bars are randomly selected from various retailers and then analyzed. In the latest survey (2008), the average amount of lead detected was seven times lower than the FDA’s level of concern for children.
If you like dark chocolate, you’ll have to weigh known benefits against the probability that you are eating a bit of lead. Dark chocolate is far more concentrated than milk chocolate. As a result, the FDA identifies dark chocolate as the chief source of lead in chocolate.
REFERENCES
Cidell JL, Alberts HC. 2006. Constructing quality: The multinational histories of chocolate. Geoforum. 37(6): 999-1007. doi: 10.1016/j.geoforum.2006.02.006. http://www.sciencedirect.com/science/article/pii/S0016718506000388
Manton WI. 2010. Determination of the provenance of cocoa by soil protolith ages and assessment of anthropogenic lead contamination by Pb/Nd and [lead isotope ratios. Journal of Agricultural and Food Chemistry. 58(2):713–721.
Rankin CW, Nriagu JO, Aggarwal JK, Arowolo TA, Adebayo K and Flegal AR. 2005. Lead contamination in cocoa and cocoa products: isotopic evidence of global contamination. Environmental Health Perspectives. 113(10): 1344–1348. doi: 10.1289/ehp.8009. Also available at: http://www.michigan.gov/documents/80091_164503_7.pdfEHPLeadcocoa.pdf
U.S. Food and Drug Administration. 2005 (revised 2006). Guidance for Industry: Lead in candy likely to be consumed frequently by small children: recommended maximum level and enforcement policy. http://www.fda.gov/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/ChemicalContaminantsandPesticides/ucm077904.htm
{ 10 comments… read them below or add one }
Hi Mary! Thank you for the post! It made me think of last year’s advent calendar scandal, where toxins from chocolate packaging were found to have leached into children’s chocolate.
http://www.mindthesciencegap.org/2013/02/15/chocolate-a-taste-of-developing-countries/
I’m sure the problem is not exclusive to advent calendars…
Overall, I think that you get the message across, but I found the post a bit ‘jumpy’. This partly has to do with the narrative order within sections, but also with the lengths/external order of sections (e.g. paragraphs that are too short or stand-alone sentences). For example, you could have joined the ‘double disconnect’ paragraph with the end of the ‘good luck’ paragraph at the beginning of the section. This way, you don’t have to interrupt the coherence from farming to shipping, and you can still go straight to the ‘lead’ hook. As you are focusing on lead in the post, you may need to hint at it in the title, otherwise readers will expect an article on the usual developing country trade/labour/inequality issues, and you might lose potential readers who are interested in the topic (and who haven’t done a tag search). Looking forward to the next post!
Angela,
Your input is wonderful! Thank you for reading my post and taking the time to offer suggestions.
I had read about lead leaching from candy wrappers in candies imported from Mexico (the FDA addressed the issue). But I had not read about the issue with chocolates in German and Swiss advent calendars. I just looked up a few articles and it’s fascinating. I might write a separate blog post on that issue.
It appears that various toxins are present in “recycled” packaging materials (e.g., heavy metals, bisphenyl A, polycylclic aromatic hydrocarbons, mineral oils). Even with a foil layer separating the recycled paper from the chocolate, certain foils allowed leaching of toxic mineral oil.
Thanks again for your interest!
Mary
Insightful post. The link to the FDA’s Total Diet Study seems to be broken/incorrect.
Robb,
I just fixed the link to the FDA Total Diet Survey. Thanks for reading my post . . . and referring to it as “insightful.”
Mary
Are there any lead figures for dark chocolate? The implication of the article is that the lead levels are high, but nothing in the article indicates what levels have been found or suspected.
Interesting post, though it might be worth noting that the concentration of cacao in dark chocolate both increases the potential for lead exposure AND increases the degree that other health benefits (which have been bandied about in the news) are also achieved. So, part of the challenge is to offset the incremental risk vs. the incremental benefits.
Dr. Zikmund-Fisher,
I am delighted that you read my post. I appreciate your comment regarding incremental risk-benefit. I found it difficult to put the lead risk “in context” since I could not find much data on lead concentrations in dark chocolate. As someone who eats a fair amount of dark chocolate, I will assume the benefits far outweigh the risks until I find out otherwise.
Mary
Well researched and interesting post. If we still have Dr. Zikmund-Fishers attention, I’d be interested in hearing a risk assessment analysis from him.
Maybe someday we’ll have in home blood testing that can determine levels of needed nutrition and problem contaminants before settling down for a meal.
In the meantime, what would he think of situational chocolate consumption. Cut down on dark chocolate if one is or is about to be pregnant? If one is already in a lead contaminated area? Children?
Since the post above mentions that the FDA is somewhat screening milk chocolate aimed at children, in my opinion, pressure for more screening ought to lead to better control. I advocate more oversight and more overall public disclosure of food sourcing and analyses.
I found this blog very interesting. I liked how even though you cannot find which country the chocolate originated from but there was still information on the general location of the cocoa bean farm. One thing I learned is that there can be traces of lead in chocolate and where the lead comes into the chocolate. One thing I found surprising was how dark chocolate has more lead in it. I found this surprising because dark chocolate is healthier for you as opposed to milk chocolate except now I know there is a reason to eat milk chocolate over dark chocolate. One question I have is what are some effects of consuming lead in chocolate? #SPX9
Lucia,
You bring up a really good point I wish I had covered in my article when you say that “dark chocolate is healthier for you as opposed to milk chocolate.” The more of the cocoa bean you eat, the more health benefits you get. It’s hard to say whether the risk of a very small amount of lead outweighs all the benefits of dark chocolate.
Dark chocolate is healthier for you than milk chocolate because it contains more of the original cocoa bean. The cocoa bean has the flavonoids (an antioxidant), which is where chocolate gets its health benefits. Also, dark chocolate usually contains less sugar than milk chocolate (and none of us needs more sugar). Also, the only fat in really good dark chocolate is “cocoa butter,” which is a healthy fat. Many milk chocolates (and cheaper dark chocolates) replace most of the cocoa butter with unhealthy fats.
You ask a great question about the effects of consuming lead in chocolate. First, please realize the amount of lead detected in chocolate is a very very small amount. So small that I could not find a study on the health effects of consuming lead in chocolate. So I will answer your question with general information about the health effects associated with exposure to lead in general:
Infants and children are most vulnerable to the harmful effects of lead because their growing bodies absorb lead more easily and get rid of it less efficiently than adults. For infants and children, exposure to lead–over time– can interfere with intellectual and behavioral development. Studies have actually shown lead to be linked to lower IQs. The children in these studies may have lived in homes with peeling lead paint or areas of a city that had lead on the soil the children may have played in or tracked into the house. This would be much more lead than you could be exposed to in a chocolate bar.
Personally, I think it is best to follow the advice “moderation in all things” and just not go overboard when eating chocolate.
Thanks for your thoughtful comments.
Mary