Cooking & Baking

Cacao's Dark Side

Chocolate is made from the cacao bean, which has two main components: cocoa solids and cocoa butter. Together, these are called cacao or cocoa. 

Dark chocolate’s reputation as a relatively healthy treat stems mostly from the cocoa solids. These are packed with flavanols, which are antioxidants linked to improved blood vessel function, reduced inflammation, and lower cholesterol. Dark chocolate is also lower in sugar and higher in fiber than milk chocolate, and it has magnesium and potassium. Unfortunately, cocoa solids are also where the heavy metals, especially cadmium, lurk. That makes it tricky to balance dark chocolate’s risks and benefits.

Some of the same concerns may extend to products made with cocoa powder—which is essentially pure cocoa solids—such as hot cocoa, and brownie and cake mixes, though they have varying amounts of cacao and possibly heavy metals. 

Dark chocolate tends to be higher in heavy metals than milk chocolate, probably because of its higher cacao content. There is no official cutoff, but dark chocolates are generally at least 65 percent cacao by weight, says Michael J. DiBartolomeis, PhD, a toxicologist and former official at the California Department of Public Health who has researched heavy metals in chocolate.