Most dentists will tell you that when it comes to candy, plain chocolate is the best choice. It doesn’t get stuck between your teeth and along the gum line like chewy sweets can. It doesn’t expose your teeth to sugar for as long as hard candies do, nor is it acidic like sour candies.
Dark chocolate is even better. For one, it usually contains less sugar than milk chocolate. More, it contains compounds, some of which may actually help protect your teeth. Theobromine, for instance, is known to support natural tooth remineralization while lowering levels of S. mutans, one of the main microbes involved in tooth decay. It’s also an anti-inflammatory antioxidant – one of a great many that are naturally found in cocoa.
Dark chocolate has also been shown to stimulate nitric oxide production, protect the skin from sun damage, improve brain function, and more.
But there’s a downside. According to Consumer Reports, some brands can contain concerningly high levels of lead and cadmium. Both of these heavy metals are highly toxic.
Most folks have heard at least something about the danger of lead poisoning. No level of exposure is harmless.
Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones, where it accumulates over time. Lead stored in bone may be released into the blood during pregnancy, thus exposing the fetus. Undernourished children are more susceptible to lead because their bodies absorb more lead if other nutrients, such as calcium or iron, are lacking.
In adults, lead exposure can cause high blood pressure and problems with brain, kidney, and reproductive health. In children, it can affect brain development, among other systemic effects.
Cadmium, on the other hand, is a carcinogen that has toxic effects on the kidneys, the skeletal system, and the respiratory system. It may also cause reproductive issues. It can cause problems even at very low levels of exposure.
So how do these metals wind up in dark chocolate?
Consumer Reports cites recent research that was done in conjunction with a lawsuit against chocolate manufacturers. The study authors found that the cadmium comes from the cacao plants taking up the metal from the soil in which they were grown. The lead, on the other hand, gets introduced after harvesting.
The researchers found that the metal was typically on the outer shell of the cocoa bean, not in the bean itself. Moreover, lead levels were low soon after beans were picked and removed from pods but increased as beans dried in the sun for days. During that time, lead-filled dust and dirt accumulated on the beans.
Consumer Reports’ testing of 28 products showed that different brands and varieties had different levels of these toxic heavy metals. Using California’s maximum allowable dose level as a guide, they found five products to be below the maximum for both lead and cadmium:
- Mast Organic Dark Chocolate, 80% Cacao
- Taza Organic Deliciously Dark Chocolate, 70% Cacao
- Ghirardelli Intense Dark Chocolate, 86% Cacao
- Ghirardelli Intense Dark Chocolate Twilight Delight, 72% Cacao
- Valrhona Abinao Dark Chocolate, 85% Cacao
Five other products were found to be exceedingly high in both metals:
- Theo Organic Pure Dark, 70% Cacao
- Trader Joe’s The Dark Chocolate Lover’s Chocolate, 85% Cacao
- Theo Organic Extra Dark Pure Dark Chocolate, 85% Cacao
- Lily’s Extremely Dark Chocolate, 85% Cacao
- Green & Black’s Dark Chocolate, 70% Cacao
Of the remaining brands, some were found to be high in lead but relatively low in cadmium, while others contained very high amounts of cadmium but less than the max for lead.
You can view the full report here, which also includes some helpful tips for minimizing your exposure.