A Third of Chocolate Products Are High in Heavy Metals, CR's Tests Find

Dark Chocolate • Milk Chocolate • Chocolate Chips • Cocoa Powder • Hot Chocolate Mixes • Brownie and Cake Mixes

Heavy metals can be found in many foods—such as arsenic in rice, mercury in some types of fish, cadmium in spinach, and lead in carrots and sweet potatoes. And you can also be exposed through drinking water or your environment (such as lead paint in your house). All these sources can add up, so it is important to be aware of different pathways that contribute to your overall heavy metal intake. Chocolate may just be one of a number of contributing factors to overall heavy metal levels, but it’s a popular treat eaten by children and adults and not an essential part of a someone’s diet. So it makes sense to try to limit the amount of heavy metals people get from chocolate. 

Exposure to heavy metals is of greatest concern in children and during pregnancy, because they can damage the brain and nervous system, causing developmental delays, learning and behavior problems, and more. But adults can also experience negative effects. For example, frequent lead exposure has been linked to immune system suppression, reproductive issues, kidney damage, and hypertension.

Lead and cadmium are the two heavy metals that CR’s tests have found to be the most problematic in chocolate. Research indicates that lead and cadmium get into cocoa in different ways. For cadmium, it appears that the cocoa plant takes it up from the soil. Lead, however, can be deposited on the cocoa beans after harvest, potentially from dust and soil as beans dry outdoors. These metals are both found in the cocoa solids—which, along with cocoa butter, make up cacao. That’s why products rich in cocoa solids, such as dark chocolate and cocoa powder, tend to be higher in heavy metals.

We measured the amount of lead, cadmium, mercury, and arsenic in three samples of each food and averaged the results. None of the products posed a risk of arsenic or mercury exposure.

To assess the risk from lead and cadmium, we looked at whether a serving of each product would expose someone to California’s standard maximum allowable dose levels (MADL) for lead (0.5 micrograms per day) and cadmium (4.1 mcg per day) in food. Note that as part of a settlement to a lawsuit currently in place brought by As You Sow, an organization that pushes for corporate accountability, the vast majority of chocolate products sold in the state are subject to less stringent standards, while companies work to reduce the levels of metals in their chocolate products.

CR’s scientists measured heavy metal content against California’s standard levels because there are no federal limits for the amount of lead and cadmium most foods can contain, and they believe that California’s standard levels are the most protective available. However, our tests are not assessments of whether a product exceeds California’s or any other legal standard—they are meant to indicate which products had comparatively higher levels of heavy metals. 

Our results are shown by category in the charts in each section below. We list the percentages of the standard MADL levels for lead and cadmium supplied in one serving of the foods. While both heavy metals increase the risk of serious health problems, products within each category are listed in order of lead level, because that heavy metal poses particular concerns and no amount of it is considered safe.

When we tested dark chocolate bars last year, we found lead or cadmium levels above CR’s thresholds in 23 of 28 bars, or 82 percent of them. Our results this time were similar. Of the seven bars we tested, five, or 71 percent, were above our levels for lead, cadmium, or both.

Two bars—Divine 70% Deliciously Smooth Dark Chocolate and Sam’s Choice (Walmart) Dark Chocolate 85% Cocoa—fell below CR’s levels for both lead and cadmium, based on a serving of about 1 ounce. (The following bars also came in below our thresholds when we tested them last year: Ghirardelli Intense Dark Chocolate 86% Cacao, Ghirardelli Intense Dark Chocolate Twilight Delight 72% Cacao, Mast Organic Dark Chocolate 80% Cocoa, Taza Chocolate Organic Deliciously Dark Chocolate 70% Cacao, and Valrhona Abinao Dark Chocolate 85% Cacao.) 

Eating an ounce of four others would put you over our limit for lead. The Perugina Premium Dark Chocolate bars had the highest amounts. One of the four, Evolved Signature Dark 72% Cacao Chocolate Bar was high in both lead and cadmium. Another bar, Sam’s Choice Dark Chocolate 72% Cocoa, was high in cadmium only. 

Nestlé, which owns Perugina, told CR, “We apply strict standards to ensure our products are high quality and comply with all applicable regulatory requirements, including limits for cadmium and lead.” And Rick Gusmano, co-founder of Evolved Chocolate, said the company’s chocolate products fall well below levels set in the As You Sow settlement and that the company “regularly tests raw materials and finished goods to ensure compliance and, ultimately, consumer safety.” Other makers of dark chocolate with high levels of lead or cadmium did not respond to a request for comment. 

Milk chocolate tends to be lower in heavy metals than dark chocolate because it has less cocoa solids. And in fact none of the five milk chocolate bars in our tests were over CR’s limit for either heavy metal. Hershey’s Milk Chocolate bar had the most lead, reaching 67 percent of CR’s limit. Feastables Mr. Beast Bar Milk Chocolate, with 80 percent of CR’s limit, had the most cadmium per serving. Lindt Classic Recipe Milk Chocolate Bar was the lowest overall, with one serving (about 1 ounce) containing 11 percent of the daily maximum amount of lead and 13 percent of the daily cadmium limit.

None of these 12 products had high levels of cadmium, and only two—Hu Dark Chocolate Gems and Good & Gather (Target) Semi-Sweet Mini Chocolate Chips—were over CR’s limit for lead. 

But there’s a caveat: The serving size for chocolate chips is just around ½ ounce (about 1 tablespoon)—the amount you might expect to get in a cookie or two, depending on the size of the cookie. If you’re the type that likes to eat more than a few cookies, or a handful of chips straight out of the bag, with many of these you could exceed the daily limits for both cadmium and lead by eating just two servings. Some good options for snacking that are relatively low in both heavy metals are 365 Whole Foods Market Semi-Sweet Chocolate Baking Chips, Kirkland Signature Semi-Sweet Chocolate Chips, and Nestlé Toll House Semi-Sweet Morsels. 

A spokesperson for Hu told CR that our test results were in line with the company’s own testing, but added that those levels fall far below those set in the As You Sow lawsuit settlement. Target did not respond to a request for comment.

Cocoa powder is almost all cocoa solids, so you might expect that most would be too high in lead and cadmium, even in small amounts. But none of those we tested were high in cadmium, and only two had high levels of lead. 

Most of the cocoa powders in our tests were natural-style—the kind most commonly available in the U.S.—and of those, a serving (1 tablespoon) of Hershey’s Cocoa Naturally Unsweetened 100% Cacao exceeded our lead limit. 

Droste Cacao Powder was the only Dutch processed cocoa in our tests. This type of cocoa is alkalized to give it a less bitter taste. It was also the highest in lead of any product in our tests, supplying 324 percent of CR’s limit. 

The best cocoa powder overall was Navitas Organics Organic Cacao Powder, which reached 77 percent of CR’s lead limit and 17 percent of the cadmium limit. Navitas has a third party test all finished products for heavy metals to ensure low levels, according to the company website.

Neither Droste nor Hershey responded to a request for comment.

These mixes contain cocoa powder plus sugar and other ingredients, so we expected that they would be relatively low in lead and cadmium. That’s not what we found. Four of the six mixes we tested exceeded our lead limit: Great Value (Walmart) Milk Chocolate Flavor Hot Cocoa Mix, had the highest levels, with mixes from Trader Joe’s and Nestlé (which also makes hot chocolate mix for Starbucks), above CR’s cutoff. 

The Nestlé spokesperson said that the company stands by the safety of its products and that it works with its “suppliers on an ongoing basis to closely monitor and minimize the presence of these substances in our foods as much as possible.” Other makers of hot chocolate with high levels of lead did not respond to requests for comment.

These products fared well overall in our tests. None were high in cadmium, and just one brownie mix and two cake mixes exceeded CR’s lead limits—one by quite a bit. One serving of Bob’s Red Mill Gluten Free Chocolate Cake Mix had 216 percent. The heavy metal levels refer to the amounts of the mix that are in one serving of the finished cake or brownie. (We list the number of servings each mix makes in the charts below.) 

However, the serving sizes are small. For instance, Duncan Hines Devil’s Food Cake mix makes a cake that the manufacturer says will serve 10. The company’s Double Fudge Brownie mix makes 20 servings. If your cake or brownie portions are more generous, keep in mind that you’ll be getting more lead and cadmium than we list here. 

Bob’s Red Mill, Simple Mills, and Ghirardelli did not respond to requests for comment.

Since any intake of heavy metals can be harmful over time, it’s important that products contain the lowest amount possible. There are ways for manufacturers to reduce the heavy metals in their products—such as sourcing chocolate from areas that have low levels of cadmium in the soil, and making improvements in cocoa harvesting, processing, and cleaning procedures. 

CR reached out to an industry trade group as well as the Food and Drug Administration for comment.

“Chocolate and cocoa are safe to eat and can be enjoyed as treats, as they have been for centuries,” says Christopher Gindlesperger, senior vice president of public affairs and communications for the National Confectioners Association, a candy industry group. “Food safety and product quality remain our highest priorities, and we remain dedicated to being transparent and socially responsible.”

The Food and Drug Administration told CR that “While the presence of cadmium and lead in chocolate has been the subject of considerable media attention, experts from around the world have found that chocolate is a minor source of exposure to these contaminants internationally.” And the agency added that “ all food manufacturers and processors are responsible for ensuring the safety of their food."

Our results, however, show that some companies may be doing a better job of keeping metals out of their products than others. That’s true even for dark chocolate and cocoa powders. “In general, products with higher cocoa content tend to have higher levels of metals, but not always,” says Eric Boring, PhD, a CR chemist who oversaw our chocolate tests. “There’s enough variation in the lead levels within each category of foods that it’s clear factors other than cocoa content affect lead levels, and that means manufacturers have the ability to reduce the heavy metals in their products to the lowest levels possible.”

For example, if Navitas Organic Cacao can be lower in lead, Boring says, why can’t Hershey’s make a cocoa powder that is lower in the heavy metal, too?

Brian Ronholm, director of food policy at CR, adds that "Earlier this year, a Hershey executive stated that the company continues to look for ways to remove more of the metals through additional cleaning and alternate sourcing. We would like for them to honor that commitment."

“Since the metals occur naturally in soil, it may seem that it would be difficult to reduce contamination, but there are some steps that chocolate makers can take to make their products safer,” Ronholm says. These include sourcing from areas with lower levels and mixing beans from different areas to ensure that the final product has lower levels. Producers could also test lots of cocoa to identify problem areas and reject particularly contaminated lots, he says.

• As much as possible, it makes sense to try to avoid heavy metals in your diet—but that doesn’t mean you should never eat chocolate.

• Kids and pregnant people should consume dark chocolate sparingly, if at all, because heavy metals pose the highest risk to young children and developing babies. And if you do eat it, pick products that our tests showed to have lower levels of heavy metals. When consuming other cocoa-containing items—like hot chocolate or brownies—it may be best to limit these to not every day, and also choose products lower in heavy metals. And, of course, you should limit how much you eat other foods that tend to be high in heavy metals, such as rice and rice products, carrots, and sweet potatoes.

• Milk chocolate can be a fine alternative for those who want to limit heavy metal exposure, but don’t treat it as a health food—it’s packed with more sugar than dark chocolate, and should still be consumed in moderation.

• For other adults who want to eat dark chocolate, occasional consumption won’t necessarily expose you to extremely high levels of heavy metals. But as much as possible, try to be aware of potential metal exposure from multiple sources. For more tips, see our previous article on metals in chocolate. 

• When consuming hot chocolate, brownies, chocolate cake, and other cocoa-containing products, know that they can contribute to your overall heavy metal burden. As with other types of chocolate, these are best consumed in moderation.