When most people think about heavy metals in food, they probably picture highly processed snacks or contaminated seafood rather than the everyday staples sitting in their pantry. But according to experts, some nutritious foods can naturally absorb or accumulate concerning levels of metals like arsenic, cadmium, and lead depending on how they’re grown, processed, or sourced.
Does that mean you have to swear off your favorite protein smoothie or stop eating vegetables altogether? Certainly not. However, it’s important to understand which foods may be more susceptible to contamination. We spoke to Dr. Elizabeth Rubin, MD and Dr. Bryan Quoc Le, a food scientist, food industry consultant, and author of the book 150 Food Science Questions Answered: Cook Smarter, Cook Better, to highlight several commonly consumed foods that can contain surprisingly high levels of heavy metals. He warned against rice, protein powders, and more. Find all of his expert insight below.
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1. Rice
Rice—particularly brown rice—might have high arsenic content because rice plants absorb water and nutrients directly from flooded soil. Over time, arsenic can accumulate in the grain, especially in the outer layers of brown rice.
"Rice is perhaps the most well-known source," Dr. Rubin said. "It takes up arsenic from the ground where it grows more easily than other types of grains. Arsenic tends to be more prevalent in brown rice than white rice; this is because part of the grain is left intact during processing. "
Experts generally recommend varying your grains instead of eating rice at every meal. Swapping in quinoa, farro, oats, or cauliflower rice occasionally may help reduce long-term exposure.
2. Protein Powders
"Some plant-based protein powders also test high for lead and cadmium, particularly those produced from rice, cacao, and pea proteins," Dr. Rubin says. Since these powders are highly concentrated products, any contaminants present in the original crops can become more concentrated during processing.
This doesn’t mean all protein powders are unsafe, but experts recommend choosing brands that undergo third-party testing and avoiding excessive daily consumption from a single source.
3. Root Vegetables
Potatoes, carrots, and turnips are nutritional powerhouses packed with fiber and vitamins, but Dr. Le says they can be vulnerable to contamination.
"Foods that can contain high levels of metal contamination include root vegetables such as potatoes, turnips, and carrots," he explains. "Root vegetables often absorb the highest amounts of metals because these are the storage organs of the plant, and so whatever is contaminating the surrounding region goes straight to these root structures."
Because these vegetables grow directly in soil, environmental contamination from industrial pollution, pesticides, or naturally occurring metals can sometimes accumulate in the edible portion of the plant.
4. Grapes
Grapes may seem like a surprising addition to the list, but Dr. Le says pesticide use plays a major role.
"Grapes tend to be heavily sprayed with metal-containing pesticides because of their susceptibility to certain molds," he says.
This can potentially increase exposure to trace metals depending on farming practices and sourcing. Washing produce thoroughly may help reduce some surface residue, though it won’t necessarily remove metals absorbed internally.
5. Chocolate
Yes, even dark chocolate could contain heavy metals. Cocoa plants can absorb cadmium and lead from soil, particularly in regions with heavy industrial pollution.
"Cocoa is grown in regions in the world where heavy industry and contamination leads to high accumulation of metals in the pod," Dr. Le explains.
Dark chocolate often contains higher cocoa concentrations, which may increase the likelihood of elevated metal levels compared to milk chocolate. Still, moderation is key, and occasional consumption is unlikely to pose a major issue for most healthy adults.
6. Pork
According to Dr. Le, pork products can also sometimes contain elevated levels of heavy metals due to animal feed practices.
"Pork tends to be fed the remains of food waste, which can be heavily contaminated with metal," he says.
As with many foods, contamination levels can vary significantly depending on farming standards, feed quality, and sourcing practices.
What Heavy Metal Exposure Can Do To The Body
Heavy metals can accumulate gradually in the body over time, especially with frequent exposure. Dr. Le says this may contribute to a range of symptoms and health concerns.
"The accumulation of heavy metals in your body can lead to fatigue, compromised immune function, headaches, chronic inflammation, and other biological issues," he explains.
He also notes that while some metals are needed in tiny amounts for normal bodily function, excess exposure can become harmful. "Excess levels of metals can create a massive problem with oxidation, as they tend to catalyze many of the reaction between oxygen and other parts of your body," he says. "This can take a heavy toll on your neurological and endocrine systems."
Fortunately, most healthy adults can naturally eliminate some heavy metals. "The body is capable of excreting a sizable amount of heavy metals," he says. "It’s also important to vary your food intake from different sources, as it will help offset any potential limited accumulation."
"Peer-reviewed scientific tools that are used to assess and screen heavy metals in food can be useful for understanding which foods contain high levels of heavy metals," he concludes, pointing to the Metal Dietary Exposure Screening Tool developed by the Institute for the Advancement of Food and Nutrition Sciences (IAFNS).
Good to know!
