What heavy metal risks are in food?Updated 9 months ago
Heavy Metal Risks by Metal Type
Arsenic
carcinogenic + many detrimental health and developmental effects
Prop 65 No Significant Risk Level (NSRL) for arsenic is 10 µg/day
Baby Food Safety Act of 2021 proposes 10 ppb for non-cereal food and 15 ppb for cereal
Highest Risks
Rice plants, due to their physiology and growing conditions, accumulate 10 times more arsenic than other grains. Because arsenic accumulates in the outermost layers (the bran and germ) which are removed in white rice, brown rice tends to have higher arsenic levels, as does rice from Texas, Arkansas, and Louisiana. EU limits range from 0.02 mg/kg in baby food to 0.3 mg/kg in rice crackers. The FDA action level for infant rice cereals is 100 ppb or 100 µg/kg.
Fruits (esp. grapes/raisins, blueberries, cantaloupe) also tend to absorb more arsenic, which in turn contributes to arsenic in dried fruit, juice, and wine. The EU limit for fruit juice is 0.02 mg/kg, while the FDA action level for apple juice is 10 ppb or 10 μg/kg.
Root vegetables like beets, turnips, carrots, radishes and potatoes absorb arsenic mostly in their skins. Peeling these vegetables will get rid of most of the arsenic.
Although seafood can take in arsenic from seawater, most of it is in a less harmful organic form called arsenobetaine. However, Hijiki seaweed can contain arsenic in its harmful inorganic form.
Animal product disclaimer: As of 2016, it is no longer legal to use drugs containing arsenic to encourage growth and treat disease in livestock in the United States. Since arsenic occurs naturally in soil and water, low levels of arsenic could occur in some meat or animal products like dairy or eggs.
Lower Risks
Low-arsenic grains include barley, faro, couscous and bulgur wheat. Gluten-free alternatives that are low in arsenic include buckwheat, millet, quinoa, oats, cornmeal, grits and polenta.
Fruiting vegetables like tomatoes, peppers, squash, cucumbers, peas, beans, and corn absorb very little arsenic in the parts that you eat.
White rice tends to have lower concentrations of arsenic than brown rice because arsenic accumulates in rice’s outermost layers, which are removed in white rice. Rice varieties grown in California or imported from Southeast Asia are often lower in arsenic than rice grown in other parts of the U.S.
Silver Lining: While it is not possible to remove arsenic from food, the majority of arsenic (~70%) is excreted from the body within a couple days. The remainder makes its way into skin, hair, and nails, where it can be eventually excreted. Dietary nutrients including Vitamins A, C, and E, polyphenols, and curcumin as well as zinc and selenium may reduce the arsenic toxicity in the body.
Cadmium
carcinogenic, kidney toxicity, bone demineralization
Prop 65 Maximum Allowable Dose Level (MADL) for cadmium is 4.1 µg/day
Baby Food Safety Act of 2021 proposes 5 ppb for non-cereal food and 10 ppb for cereal
Highest Risks
Low levels of cadmium have been found in all food groups.
The highest concentrations of cadmium have been found in shellfish, organ meats (liver and kidney), vegetables (esp. leafy & root/tuber vegetables), nuts & seeds (esp. sunflower), spices, and coffee, tea, and cocoa. EU limits for shellfish range from 0.5 - 1 mg/kg; animal products range from 0.05 - 1 mg/kg; vegetables range from 0.02 - 0.2 mg/kg; nuts range from 0.2 - 0.3 mg/kg; seeds range from 0.1 - 1.2 mg/kg; cocoa products range from 0.1 - 0.8 mg/kg. The FDA intends to issue Draft Guidance on Cadmium in Foods Intended for Babies and Young Children in 2024.
Foods that are more commonly eaten contribute much more to cadmium exposure, regardless of their concentration levels. The food groups that contribute the most to dietary cadmium exposure are grains, vegetables, nuts, legumes (esp. peanuts, soybeans), roots and tubers, and animal products. In addition to the above limits, EU limits for grains range from 0.05 - 0.2 mg/kg; legumes range from 0.04 - 0.1 mg/kg; roots and tubers range from 0.02 - 0.2 mg/kg.
Lower Risks
Lower concentrations of cadmium are found in fruit, eggs, dairy, and fish.
Animal muscle meat has much lower concentrations than organ meat.
Mixed origin chocolate and chocolate products with lower cacao content have lower cadmium concentrations.
Organic grains may have as much as a 48% decrease in cadmium levels compared to conventional grains. Unfortunately for vegetables and fruit, organic certification does not seem to correlate to lower levels.
Silver Lining: Most cadmium passes through the body without being absorbed, with most healthy adults only absorbing an estimated 2.5% of cadmium consumed in food. Eating a balanced diet rich in micronutrients like zinc, calcium, and iron can reduce cadmium absorption. In addition, catechin compounds, which are high in cacao and many fruits, may inhibit cadmium absorption.
Lead
potent neurotoxin, kidney toxicity, cardiovascular effects
Prop 65 No Significant Risk Level is 15 µg/day
Baby Food Safety Act of 2021 proposes 5 ppb for non-cereal food and 10 ppb for cereal
Higher Risks
Root and tuber vegetables (e.g. carrots, sweet potatoes, beets, potatoes, cassava, and onions) as well as leafy vegetables (esp. spinach) tend to absorb the most lead.
Imported spices may be adulterated with lead during drying, from grinding machinery, or from the illegal addition of lead chromate pigment to enhance color and add weight. The highest concentrations have been found in vibrant spices like turmeric, chili powder, curry, masala, adjika, and Georgian saffron. Contaminated spices most often come from Georgia, Pakistan, Nepal, Morocco, and Bangladesh.
Imported candy is at higher risk of lead contamination, particularly candy from Mexico, Malaysia, China and India that contains chili powder from unwashed chiles, mined salt, or tamarind. Chocolate also may have elevated lead. The FDA action level for lead in candy is 0.1 ppm.
Baby food: The FDA action levels for lead in processed baby food are 20 ppb for root vegetables; 20 ppb for dry infant cereals; and 10 ppb for all other processed baby foods, including fruits, pudding, and meat.
Pervasive lead in the environment may contaminate a wide variety of foods after they have been harvested and during the processing phase. The EU Food Safety Authority sets limits for fruit, vegetables, mushrooms, grains, legumes, animal products and fish, spices, honey, juice, oils, and baby food. The FDA recently proposed an action level of 10 ppb for apple juice and 20 ppb for other juices.
Lower Risks
In general, foods produced with good agricultural practices (GAP) and good manufacturing practices (GMP) should theoretically have lower lead contamination. Most fruits and vegetables (other than roots and tubers) do not readily uptake lead unless soil concentrations are very high. However, because lead from the environment can still land on their surfaces, it’s important to properly wash plants before eating or processing them.
Silver Lining: With the exception of root vegetables, most crops do not readily uptake lead unless there are very high concentrations in the soil, suggesting that lead exposure may be reduced through better agricultural practices and processing methods. To reduce the absorption of lead, it is also recommended to eat a diet rich in micronutrients like iron, calcium, and vitamin C.
Mercury
potent neurotoxin, accumulates in the body over time
Baby Food Safety Act of 2021 proposes 2 ppb
Highest Risks
Fish and shellfish: Within aquatic environments, mercury is converted by bacteria into methylmercury, a more toxic form that is more readily incorporated into living tissues and biomagnified as it moves up the food chain. Nearly all fish and shellfish contain trace amounts of methylmercury, with fish that eat other fish (e.g. shark, swordfish, marlin, bigeye tuna, king mackerel) having the highest levels. EU limits for seafood range from 0.3 mg/kg to 1 mg/kg depending on species. The FDA Action Level for mercury in aquatic animals is 1 ppm.
Lower Risks
In general, smaller fish that are low on the food chain (e.g. anchovies, herring, Atlantic mackerel, sardines) have lower mercury concentrations than large fish that eat other fish. The FDA provides advice on choosing the best fish to eat, how often to eat them, and which fish to avoid based on their mercury levels.
Silver Lining: While it is not possible to prevent or remove methylmercury in seafood, most seafood does not have levels that would result in health effects for adults. Even children and pregnant women can safely eat 2 servings per week of fish on the FDA’s “best choice” list.
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