Chocoholics of the world: your passion is suddenly problematic. No, it’s not the same old sugar-turns-into-fat thing. This time we’re talking about lead and cadmium, “heavy” metals found in the solids in cocoa beans that give chocolate its flavor. The first, lead, is collected when dust in the places where chocolate is processed falls on the beans. The second, cadmium, may be found naturally in soil or deposited there via discarded trash such as batteries and then make its way into cocoa beans as the plants grow. Consistent long-term exposure to even low levels of either of these metals has been linked to various health problems such as brain and nervous system damage among fetuses and young children.
For adults, the most common adverse effects are weakening of the immune system, reproductive difficulties, kidney damage and high blood pressure. How much gets in to the beans which get into your chocolate is still a measure of who’s measuring. The Feds set standards for heavy metals in baby food last February, and the FDA is currently working on how much cadmium is acceptable in other plant foods.
Last month, the Harvard Heart Letter published data from a Consumer Reports report measuring lead and cadmium content in a list of chocolate products from candy bars to brownie mixes. Absent Federal specifics, CR used numbers set by California to rank chocolate for grownups as low, medium, and definitely pass up this one. The Golden State’s golden standard for allowable lead is 0.5 micrograms (mcg/1,100thof a milligram) per day; 4.1 mcg cadmium. While dark chocolate is lower in sugar and fat than milk chocolate, it has more cacao and by that measure, a single ounce of 23 of the 28 dark chocolate bars CR tested would put an adult over the daily limit for at least one of the two metals; five bars were over the limit for both.
The CR test products included chocolate from big-name brands such as Nestle, lesser-known specialty makers such as Droste and Divine, and national retailers like Trader Joe’s. As you might expect, the darker the chocolate, the higher the metal content. According to CR Director James E Rogers, “every product we tested had detectable amounts of lead and cadmium.” However, if you stick to a single ounce rather than an entire bar, Whole Foods’ Divine 70% Deliciously Smooth Dark Chocolate and Walmart’s Sam’s Choice Dark Chocolate 85 percent Cocoa came in under the limit. Moving on to milk chocolate which has fewer cocoa solids than dark chocolate moves the dial. Not one of the five bars CR tested were too high per ounce. The best of the betters: Lindt Classic Recipe Milk Chocolate Bar with about “11 percent of the daily maximum amount of lead and 13 percent of the daily cadmium limit.”
Which leaves cocoa, chips, and cakes. CR says limit yourself to one serving a day–no multiple spoons of chips, no whole cakes, no whole pots of hot chocolate–and you’re good to go. At which point you can take the time to consider the kind of contrasting good news/bad news food facts that makes nutrition fascinating. Fact One: Cocoa beans and dark chocolate are rich in iron, a “good” metal that enables red blood cells to carry oxygen to every tissue in your body. Fact Two: Like cocoa plants, some grains such as brown rice, most leafy greens, and several root veggies such as carrots grown close to or in soil which, as CR notes, may raise their “bad” metal cadmium content. How much is too much is a work in progress.
While the Fed agencies work to set safe standards for the Fact Two foods, anyone here for low-fat vanilla ice cream? With no more than a teaspoon of chocolate syrup, of course.