Health organizations have been very thorough when it comes to warning people about the dangers of mercury in certain fish—but that’s not the only so-called heavy metal to infiltrate our food supply. There’s growing concern about many other heavy metals in food, notably lead and cadmium and the intermediate element arsenic (called “intermediate” because its chemical and physical properties fall somewhere between a metal and a nonmetal). While these and other elements are in many foods, it’s particularly troubling that some of those foods top the most-healthy lists.
How heavy metals get into the food chain: While processing and packaging sometimes can impart heavy metals into foods, the main route is from the soil they’re grown in. Heavy metals can occur naturally from elements in the earth itself and also from contamination from a variety of sources, including industrial mining near farmlands, water runoff, pesticides and fertilizers. There are wide variations in the amounts of these contaminants that any one plant takes in, and while organic foods are free of pesticides and other chemicals, they still can pick up metals naturally found in the ground unless growers have remediated the soil to eliminate those contaminants.
Problem: Heavy metals don’t degrade quickly—they can remain in soil for hundreds of years. And they can accumulate in your body over time. They’re especially dangerous to pregnant and nursing women, infants and young children because they can lead to developmental problems.
Here’s what you need to know about good-for-you foods that have raised alarms, from nutrition consultant Lisa R. Young, PhD, RDN, CDN/LDN…
Brown rice. This grain —and all rice foods including rice cakes, milks and cereals—can have high levels of arsenic, increasing risk for cancer, high blood pressure, diabetes and respiratory diseases. Because rice is very porous, it can absorb a lot of arsenic from the soil and water it’s grown in—more than any other food crop. White rice has far less arsenic because a substantial amount is removed during processing, but so, too, are nearly all the rice’s nutrients.
What to do: As often as possible, substitute another whole grain such as barley, bulgur and buckwheat (kasha) for rice, all of which are less likely to have arsenic. When you choose to eat rice, do so in moderation. Important: Because of arsenic’s link to developmental problems, babies and young children and pregnant and nursing women should not have any rice or rice-based foods (read all labels, including those on baby formulas).
Spinach. The heavy metal cadmium is associated with kidney disease, weakened bones and many types of cancer. Cadmium accumulates in the outer leaves of spinach as well as lettuce, parsley and other leafy greens.
What to do: The positives in foods often outweigh the negatives, but just because a food is good for you doesn’t mean you should have it every day. Eat spinach only once a week, and vary your leafy green vegetables. Also remove the outer leaves. Rule of thumb: Eat a rainbow of vegetables and fruits to get a variety of healthful phytonutrients.
Dried spices. Arsenic, lead and cadmium are just a few of the heavy metals found in the spices in your pantry. In 2021, Consumer Reports tested 126 name-brand products and found that almost one-third had heavy metal levels high enough to raise health concerns and 31 exceeded the maximum amount anyone should have in a day. Lead is a particular concern because unscrupulous vendors sometimes add it to bulk spices to increase their weight so they can charge more money—that was how 2,000 times the amount of lead considered “safe” ended up in kids’ applesauce pouches in the fall of 2023, spurring a massive recall. On July 25, 2024, the FDA sent out a warning about the El Servidor ground cinnamon product—this is just the latest cinnamon on the FDA’s list. (You can see the full list at FDA.gov (search “FDA Alert Concerning Certain Cinnamon Products Due to Presence of Elevated Levels of Lead.”)
What to do: The New York City Department of Health recently suggested avoiding spices from the countries Georgia, Bangladesh, Pakistan, Nepal and Morocco, because spices purchased abroad are likely to have high lead levels. To reduce exposure to lead, look for US-made products. Also look for brands whose labels state they go through third-party lab testing. In the Consumer Reports tests, Spice Island, McCormick, Great Value (Walmart’s house brand) and Morton & Bassett had the lowest levels of heavy metals.
Protein powders. Independent studies done by the Clean Label Project, a national nonprofit focused on health and transparency in labeling, found that 53 of the 134 top-selling protein powder products had elevated levels of heavy metals and the industrial chemical bisphenol A (BPA)…and about 75% had measurable amounts of lead.
What to do: Not all the powders tested contained toxins. Puori, Wicked Protein and Ritual are three of the safer ones, according to the Clean Label Project (you can see all the results at CleanLabelProject.org). For a less expensive protein option with a natural calcium boost, simply add one-half cup of plain low-fat Greek yogurt to your smoothies.
Bone broth. Bone broth samples have been analyzed by Consumer Lab for lead content, the concern being that lead that had accumulated in the animals’ bones could leech out during the cooking process. But the findings were contradictory. In one small controlled study of lead concentrations in three different organic chicken broths, researchers found several times the lead concentration of the water with which they were made…but another study found that both lead and cadmium levels were relatively low.
What to do: There is little concern if you’re not having bone broth every day—and there’s no reason to make it a diet staple. When making homemade stock, limit simmering time to a few hours. When buying canned stock, make sure it’s low sodium—too much salt is a greater concern for many people.
Big fish. The concern over mercury in fish bears repeating. Larger fish, such as swordfish, shark, king mackerel, tilefish and bluefin tuna, carry the greatest risk because they accumulate mercury from eating smaller fish over the course of their lifetimes.
What to do: Children and pregnant and nursing women should avoid these fish, but for others, a four-to-six-ounce piece once a week shouldn’t pose a problem. Benefit: These fish offer high-quality protein and omega-3s. Fish with the lowest mercury levels include salmon, catfish and canned light tuna (avoid white albacore). Among shellfish, it’s shrimp.
Chocolate. Original research done by Consumer Reports and published in October 2023 sounded the alarm about lead and cadmium in dark chocolate. A recent study from Tulane University drilled down further, analyzing 155 dark and milk chocolates from various global brands sold in the US. Researchers tested them for 16 metals including toxic lead and cadmium and essential copper, iron and zinc. The study also modeled the risk from eating one ounce of the chocolate per day. Only one brand of dark chocolate exceeded the international limit for cadmium of 800 micrograms per kilogram in bars with greater than 50% cacao, and only four dark chocolate bars had cadmium levels that could pose a risk to children weighing 33 pounds or less. Two bars contained lead levels above California’s interim standards for dark chocolates, but not enough to pose any risks to children or adults. The study also found that dark chocolates from South America had higher levels of cadmium and lead than chocolates from Asia and West Africa. To see the full list, go to ConsumerReports.org. Safer choices: Mast, Taza Chocolate and Ghirardelli.
What to do: On a positive note, the dark chocolates analyzed had high levels of nutrients such as copper, iron, manganese, magnesium and zinc, with several providing more than half the daily requirements. Lead study researcher Tewodros Rango Godebo, PhD, also pointed out that these essential minerals could potentially reduce absorption of toxic metals in the intestine. From a health perspective, dark chocolate is better than milk chocolate. Don’t eat it every day, but an occasional half-ounce shouldn’t pose a problem.
