Dark Chocolate Better for You? Not Always

Dark chocolate gets good press. Most consumers think it's healthier than milk chocolate. The USDA credits it with providing lots of iron and not much sugar. But is there a dark side to dark chocolate?

There is, and it has to do with cadmium and lead – two heavy metals that are linked to all kinds of health problems. Recent research by Consumer Reports found lead and cadmium in all 28 dark chocolate bars it tested.

What's worse, 23 of the bars had enough heavy metals that eating just one ounce a day would put you over the limit.

The chocolates that were high in both lead and cadmium include bars from:

Trader Joe’s
Theo
Lily’s
Green & Blacks

The safest choices of the 28 bars tested were by brands including:

Mast
Taza Chocolate
Ghirardelli
Valrhona

“Consumers are troubled that many of their favorite dark chocolate bars contain high levels of heavy metals. Many choose to eat dark chocolate because of its potential health benefits and relatively low levels of sugar. But there’s nothing healthy about ingesting heavy metals,” said Brian Ronholm, director of food policy at Consumer Reports, in a letter to food manufacturers.

Risky for all ages

While pregnant people and young children are most at risk of harm from heavy metals, the substances aren't good for anybody.

“There are risks for people of any age,” said Tunde Akinleye, the CR researcher who led the study. He pointed out that frequent exposure to lead in adults, can lead to nervous system problems, hypertension, immune system suppression, kidney damage, and reproductive issues.

It's rare for someone to eat enough heavy metal in a single sitting to cause damage but small exposures over time add up since the toxins generally remain in the body more or less indefinitely. Eating chocolate every day could be enough to cause problems, studies have found.  

Other foods – like carrots and sweet potatoes –  also contain heavy metals. That makes it easier to take in an unhealthy amount. The key, researchers say, is moderation. Eating a wide variety of food is generally regarded as a good way to get all of the necessary nutrients while avoiding toxic amounts of any one substance.

Sort of like red wine

Bread and chocolate go together nicely, in more ways than one.

For decades, red wine was regarded as being healthful in small amounts. Now, new research finds that any amount of alcohol is too much and can cause damage, especially when consumed on a daily basis.

It turns out dark chocolate may be in the same category. It's regarded as being healthier than milk chocolate but that doesn't necessarily mean it's better than no chocolate. In fact, chocolate lovers should alternate dark chocolate and milk chocolate, since milk chocolate contains fewer heavy metals, said Dr. Joshua Lambert, professor of food science at Pennsylvania State University.

Cocoa vs. chocolate

Though often used interchangeably, cocoa and chocolate aren't the same thing. Cocoa is made from the seed of a cacao tree while chocolate is made by mixing cocoa with other ingredients, usually including milk and sugar.

The key to reducing heavy metals is to look for dark chocolates with lower cacao percentages – so you're not exposed to as much of the heavy metals that may be in the seed. If you’re considering a bar that CR didn’t test, you may want to opt for a 70 percent dark chocolate product over an 80 percent one, for example, or a 65 percent bar over a 70 percent one.

The healthiest way to eat chocolate may be not at all. But as reasonable compromise is to eat both kinds – milk and dark – but not every day.