Heavy Metals in Dark Chocolate: Should You Be Concerned?

A little while back we talked about why I think you should reconsider the types of candies you’re buying and eating. That post revolved around Halloween candy but is applicable to any candy. When writing that post, I discovered that dark chocolate is very likely to/pretty much always has some amount of heavy metals and often has levels of heavy metals that are considered unsafe for human consumption. 

Today is the day we tackle that in a little more depth. Yes, chocolate lovers around the world can now lament that their favorite treat has dangerous heavy metals in it. In fact, those that have prioritized dark chocolate (like me, initially for health and then actually started liking it more) can actually expect to consume more heavy metal than those who prefer milk chocolate. 

That’s because the chocolate is the problem, not the milk or the sugar. More chocolate equals more heavy metals. Let’s get into this depressing topic. 

(But also, it may not be as bad as it seems, so take a deep breath.)

There are two major arguments floating around the internet in different camps: 1) heavy metal in chocolate is concerning and though certainly not the end of the world, is an area for improvement, and 2) heavy metal in chocolates is not concerning and people are just fear mongering. I will lay out both of these arguments so you can hopefully understand the situation better and figure out what works for you.

Understanding heavy metals and plants

Heavy metals are found in chocolate

The health implications of heavy metals

The arguments

1) Heavy metal content is not a concern

2) Heavy metal content is a concern

Summary / TLDR

Understanding heavy metals and plants

Generally speaking, heavy metals can be found in a lot of things, especially food. This is because heavy metals are actually naturally occurring and essential to life (though nowaday they’re just the boogeyman). Plants need heavy metals to perform various functions, kind of like our need for vitamins and minerals. Because of this, they uptake heavy metals (and other metals and nutrients) through the soil and sometimes even through their foliage.

The problem is that because of pollution, probably largely due to waste management, soil pretty much everywhere, and certainly worse in some places than others, has higher concentrations of heavy metals than it used to, and plants are sometimes up-taking levels that are considered toxic for them. This impacts plant functioning but can also make it into the finished food products we eat.

It does seem like some particularly healthy foods end up with a higher amount of heavy metal uptake than others, like leafy, green vegetables. Chocolate is another one that’s shown to uptake a couple heavy metals at a significant rate, varying depending on soil quality and type.

Unfortunately, until we address our waste issue globally, soil contamination and rising levels of toxins in a variety of plants and foods will continue to be a problem. I don’t think it will ever not be a problem, simply because we as an entire species are not going to give up the many comforts and technologies that we’ve grown used to, that improve our quality of life, but definitely take a toll on the planet. 

There is interesting work being done to explore the use of various plants on actually extracting contaminants from soil related to wastewater from production/mines (a major source of contamination), which would be a very interesting option to explore.

For chocolate, cadmium is the major heavy metal that is absorbed from soil. Lead is mostly accumulated during the harvesting and processing because of particles in dust and air landing on the plants and absorbing into them. There are other heavy metals involved here, but these are the major ones found at potentially concerning levels and what is being discussed.

Heavy metals are found in candy (mostly chocolate)

One review of candy consumption in Nigerian children evaluated the levels of heavy metals found in fifty common candies and sweets and found that individual candies had more lead than accepted permissible levels and that overall consumption of chocolates and candies causes higher levels of consumption of cadmium and lead than accepted standards and recommendations. This is just one example of findings that candies can tend to contain relatively high levels of heavy metals. 

Some studies are point-in-time analyses that report on the levels of various heavy metals in chocolate and what I’ve seen finds that cadmium is probably the biggest concern for appearing at a level that is worth being mindful of. Other studies are done at multiple points in time, which is good for showing that it’s not just a bad batch or a fluke reading. One most notable study like this finds that near half and about a third of samples of pure chocolate products exceed California state levels for lead and cadmium, respectively. It’s important to note that all of these studies refer to California or UK standards for safe levels, which tend to be more stringent than what the FDA mandate, though the FDA has not set limits for heavy metal content in chocolate.

In fact, researchers in California kind of kicked this off when they discovered excessive levels of cadmium and lead in a lot of chocolates, which was such a widespread issue that it launched a whole investigation into the cause of this and led to a lot of the original media coverage around this issue. If you have time, I recommend you read this report on the cause of elevated cadmium and lead levels in chocolate because it is really interesting and informative. 

We already discussed this, but essentially it seems that a lot of the cadmium content comes from the soil, which cocoa trees are absorbing. Contrary to this, the concentrations of lead appear to come not from absorption by the tree but by contamination by the cocoa nibs during the drying process and other handling.

If you’re wondering why this is allowed to happen and why these products are allowed to come to market, it’s because the law makes exceptions for products that have high levels of unsafe ingredients through natural means. In this case, the high levels of cadmium in chocolate is permitted because the tree is up taking it straight from the soil and it is not being added somewhere in the manufacturing process. This doesn’t make it less dangerous or more acceptable, but it is the way the law works. 

Though it is mostly chocolate products that have this high level of heavy metals (especially dark chocolate as it contains a higher concentration of cocoa), some non-chocolate candies have too-high levels as well. It’s mostly the chocolate though! Which is heartbreaking for us chocolate lovers. 

The health implications of heavy metals

The research is somewhat mixed on the impacts of heavy metals on health as well as the link between heavy metals like lead and cadmium and cancer risk. Though some studies show contrary findings, there are a large number of studies showing links between heavy metals (especially cadmium) and a few different kinds of cancers. Heavy metals have also been significantly linked with heart disease.

Though a lot of the concern with heavy metal exposure is referring to intake in ways other than oral exposure, and oral exposure at levels that we aren’t seeing in food consumption, we still need to be mindful of high levels because they can cause major problems. I mean there is a reason we have gotten rid of lead-based paint and other lead laced products over the years. When looking at cadmium, it is clear that oral exposure and inhalation at levels that are too high causes major issues aside from cancer, like kidney issues.

A large part of the issue with heavy metal exposure, cancer risk aside, is that the accumulation of most heavy metals is considered “chronic” because the body cannot eliminate them as well as it would with other compounds or toxins (like alcohol). If you have kidney or liver issues, you may be even more susceptible to this. Additionally, heavy metals are understood to cause oxidative stress, which generally wreaks havoc on the body by contributing to disease progression and increasing the rate of the general aging processes.

So. Finding heavy metals in chocolate is concerning, especially considering the height of the levels that are found. Even more so considering that a lot of candy is consumed by children who are very vulnerable to attacks on their immune system and the effects of oxidative stress. Is it concerning enough to mean you shouldn’t eat it or that, at the very least, you should be mindful of it?

Let’s explore the two arguments on that.

Heavy metal content in chocolate is not a concern

I’d say the stance that you don’t need to worry about consuming dark or milk chocolate seems to be the more common of the two. A lot of experts are saying that the heavy metal and chocolate issue really comes down to just a scary headline and that there’s no evidence you should be as concerned as some sources tell you to be. 

One point for this argument is that, even though the heavy metal levels are elevated above what we would ideally see, they are still low enough that an individual eating even a full ounce of chocolate a day (which is the max recommended and amounts to about 2 chocolate bars a week) would not suffer any negative consequences.

On one hand, most people probably eat less chocolate on this. On the other hand, I sometimes eat way too much dark chocolate… so it’s good to keep in mind that moderation for this food may be especially important. 

A caveat is that small children, particularly those under about 33 pounds may be more vulnerable to the impacts of the heavy metal. It’s unlikely that a child this small would be allowed to eat that much chocolate, but it is a good warning to parents of yet another reason to moderate their children’s sweets intake. In this case, making sure your young child doesn’t eat too much chocolate will be important to ensuring their exposure to these heavy metals is at a safe level. 

It is interesting to note that it has been found that the mineral content of chocolate may reduce the bioavailability of heavy metals to the body, which means that even though you may be consuming higher than ideal levels of heavy metals with chocolate, you’re not actually absorbing a lot of it and it’s being excreted with waste. This changes the conversation a little bit because it brings into play that piece that says just because you’re exposed to a toxin does not mean your body is going to take it on. That’s significant to understand.

All of this taken together leads us to believe that, while it isn’t great that chocolate has this high of levels of a couple heavy metals, it’s probably okay. It’s not ideal, but chocolate is still considered safe to eat. I’ll remind you that this determination is being made even with consideration of stricter heavy metal limits from California and the EU than the FDA would encourage.

Heavy metal content in chocolate is a concern

To bring it back a little, I think the arguments that heavy metal content in chocolate is a concern largely revolve around a few things. 1) There are objectively high levels of heavy metals in chocolate products, 2) people (rightfully, in my opinion) don’t fully trust FDA guidelines around toxicity of various compounds and chemicals and even what “experts” say is safe or not, and 3) abundance of caution.

We’ve discussed the heavy metal concentrations at length now. They are higher than we would like to see and they are the result of pollution and contamination that doesn’t need to exist in this world. But it does, so it’s there. That’s very unfortunate. 

Add to this that we are still learning so much about what’s toxic, what that even means, what small levels of toxic exposure cause over time, and people have a right to be unconvinced by various experts coming out and saying, “yeah it’s high but you’re going to be fine.” 

While I am a big advocate of following the data and even some experts, I also believe that data is incomplete and unable to paint a full picture in every situation. I’ll never fully trust it or take it at its word because “science said so.” What we know through science changes too much and what we don’t know is too vast to be that confident. So I choose to use it as a guide but not make all my decisions based on it. 

One thing people may feel is that, in combination with all of the other exposures of heavy metals, is it still wise to consume a product I know contains relatively high levels of a substance that’s arguably not good for me? Maybe not. There are a lot of sources. It’s in a lot of food, including in a lot of the healthiest foods (hey leafy, green vegetables). Can you truly know your cumulative exposure?

Experts take into account the exposure from other sources, but there’s certainly no way for them to be entirely accurate about this. I can understand if an individual feels that it’s just too much to be safe. In that case, your answer may be to avoid the product or to majorly limit it. 

This is also going to be so specific to the individual. I will admit that I eat a lot of dark chocolate. It fluctuates. Some weeks I probably eat my ounce a day, some weeks I hardly eat any, some weeks I probably eat more than an ounce a day. Chocolate is like my one treat that I just struggle to say no to, and I justify it since I don’t really eat much other junk or sugar. 

So for me, it’s good to know that moderating my chocolate intake, especially my dark chocolate intake (which is my preference), is going to be pretty important. 

This stance that the heavy metal content is a problem may also come from a place where someone tries to minimize all exposures across the board, out of an abundance of caution and because minimizing toxic exposure is a high priority to them, regardless of what anyone says may be safe or not. That’s valid if that’s where you stand. 

Summary / TLDR

Pure chocolate contains heavy metals naturally, and always would in our world at any point in history. However, due to pollution, chocolate now has much higher levels of heavy metals (particularly cadmium and lead, with cadmium being the more severe) than it should. 

While the levels of heavy metals in chocolate are considered high, they’re also considered by experts, based on solid research, to not be an issue to the average consumer. Even at the maximum or the recommended rate of consumption of chocolate products, an individual should still be safe from the negative effects of heavy metals. Add to this that most people don’t eat that much chocolate (2 candy bars a week), and most people have nothing to worry about. 

If you have young children, say under 4 years old, it’s a good idea to limit their chocolate consumption, as they are especially vulnerable to the effects of heavy metals. Additionally, if you are prone to consume excessive amounts of dark chocolate (guilty), you would do well to limit your consumption. 

On one hand, add to this the confounding variable that the other minerals in chocolate reduce the bioavailability of heavy metals to the human body, and you find chocolate is probably fine. On the other hand, if you add to this the confounding variable that chocolate isn’t your only source of heavy metal consumption, then maybe it’s more concerning than that. 

All in all, the current state of the science and expert opinions leads me to believe that dark chocolate is probably mostly safe, especially if you commit to consuming it in moderation. 

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