CPE Monthly: Regulation of Heavy Metals in the Food

November/December 2024 Issue

CPE Monthly: Regulation of Heavy Metals in the Food Supply
By Sara Chatfield, MPH, RDN, LDN
Today’s Dietitian
Vol. 26 No. 9 P. 34

Take this course and earn 2 CEUs on our Continuing Education Learning Library

Heavy metal pollution is a global environmental issue threatening food security and public health. Urbanization and industrialization around the world have led to greater accumulation and movement of waste products, contributing to the heavy metal pollution of air, soil, and water, particularly in populated areas.1,2 Heavy metal contamination of urban soil has increased dramatically in recent decades.1-3 Heavy metals in the environment can contaminate the food supply and lead to harmful effects on human health and cognition.

Heavy metals are relatively dense metals or metalloids that are toxic at certain concentrations. The heavy metals of greatest concern are nonessential for the human body, including arsenic (technically a metalloid), lead, cadmium, mercury, and chromium.1,4 While the Food and Nutrition Board has set adequate intakes for chromium, it’s not considered an essential nutrient.5 Other heavy metals of potential concern include copper, iron, nickel, and zinc.1 Although they’re essential for the human body, excessive quantities of these micronutrients can cause health problems.1

Arsenic, lead, cadmium, mercury, and chromium are among the top environmental substances endangering human health, according to the US Agency for Toxic Substances and Disease Registry (ATSDR) and the US Environmental Protection Agency (EPA).1 Heavy metals impact the health of millions worldwide.6 Populations particularly vulnerable to their effects include infants, young children, and pregnant people. Enhancing their knowledge of the risks of heavy metal ingestion from food will further RDs’ ability to help the public limit exposure. This continuing education course describes the scope of heavy metal contamination of global food sources and strategies to manage this public health hazard.

Sources of Heavy Metals in the Food Supply
Heavy metal pollution of air, water, and soil can all impact the food supply. Although there are both natural and anthropogenic (human-caused) sources of heavy metals, anthropogenic sources are the primary cause of heavy metal pollution.7 They include emissions from factories, mines, power plants, and vehicles and discharge of industrial and agricultural waste products.1,8,9 Natural sources of heavy metals include groundwater, weathering and erosion, forest fires, and volcanic ash.1,9,10

Agricultural use of pesticides, herbicides, fertilizers, livestock manure, sewage sludge, and contaminated water can also contribute heavy metals to the food supply.1 Contaminated soil and irrigation sources may be used in areas struggling to meet food production demands.11 Irrigation with contaminated sources is a major cause of heavy metals in the food supply in low- to middle-income countries. 1,12,13 In higher-income countries, air pollution and the use of contaminated fertilizer are more frequent causes of heavy metals in food.12,13

Water polluted by runoff or atmospheric deposition can contaminate aquatic foods with heavy metals like mercury.10,14 Electronic waste caused by dumping can also lead to water pollution and increased heavy metals, particularly cadmium, in crops. Heavy metal levels in crop samples grown in electronic-waste areas in China were found to be three times higher than those in control samples.4,13

Heavy Metal Contamination of Crops
Heavy metal contamination may impact food production through its adverse effects on the growth and health of crop plants. Heavy metals may also impact the nutrient content of crops; cadmium toxicity can reduce plants’ mineral content.1,13,15

The amount of heavy metals absorbed by crop plants varies by metal and plant variety.1 Certain plants take up higher quantities of heavy metals from the soil, like leafy and root vegetables.1 A study of 22 species of vegetables, including carrot, radish, sweet potato, caitai (a Chinese “stalk” vegetable), eggplant, red pepper, tomato, pumpkin, cucumber, cabbage, spinach, and lettuce, grown on contaminated farmland in China found that the leafy vegetables (like cabbage, lettuce, and spinach) absorbed the greatest concentration of heavy metals, particularly cadmium, while the melon-type vegetables (such as cucumbers and pumpkin) absorbed the least.16

Climate, weather, soil pH, crop rotation, and harvest and storage conditions and practices can also impact contaminant levels in crops.17,18 Because rice plants are grown in flooded conditions that increase the amounts of contaminants absorbed by their roots, rice tends to have higher concentrations of heavy metals, particularly arsenic and mercury, than other grains.13,19 Some studies of crops grown on contaminated urban and suburban soil have determined that their heavy metal levels were high enough to pose a risk to human health, especially for children.2,16

Health Effects of Heavy Metals
Heavy metals can cause toxicity in living organisms, including animals used for food and humans, because they bioaccumulate in the food chain and don’t easily biodegrade.8,12,14 Though humans can also absorb heavy metals through inhalation or skin contact, ingestion through water or food is a major route of exposure.2,3,12,20,21

Exposure to very high doses of heavy metals can cause acute toxicity, leading to severe gastrointestinal effects, neurological effects, or kidney failure, and may be fatal.3,6,15,22 With chronic lower-level exposure, heavy metals can build up in bone, muscle, fatty tissue, and organs and damage cells and enzymes throughout the body.1,2,6,12

Heavy metal accumulation in the body can deplete essential nutrients and may cause anemia.1,3,8,12 It can harm the bones, kidneys, liver, and lungs, as well as the cardiovascular, reproductive, and immune systems, and can cause macular degeneration in older adults.1,3,8,12,23 Heavy metals, notably chromium, cadmium, and arsenic, can cause oxidative stress and carcinogenic effects in the body.1,3,4,12 These effects are dose-dependent and may be cumulative with exposure to multiple heavy metals.3,16 Heavy metal exposure can also impact cognition and has been linked with cognitive decline in older adults and neurodevelopmental damage in children.1,3,8,12,23

Heavy Metals and Children’s Health
Heavy metal exposure during pregnancy can lead to adverse effects on the fetus. Many toxic heavy metals cross the placental barrier and can negatively impact fetal growth and development.12,24 Heavy metals can also pass to infants through breastmilk.24

Small children are particularly susceptible to the effects of dietary heavy metal exposure. Both their typically lower dietary variety and two- to three-fold higher food intake for their body weight compared with adults can lead to greater exposure.8,19,25 Furthermore, their greater intestinal absorption and lower renal secretion of heavy metals can result in more accumulation.8,25 Young children’s rapidly developing brains and nervous systems are more vulnerable to damage from toxins like heavy metals.2,19

Heavy Metal Disease Risk
The degree of heavy metal toxicity and resulting health impacts vary in individuals depending on their age, weight, sex, and other physiological factors and on the dose and type of metal, its bioavailability—the amount actually absorbed—and the route and frequency of exposure.8,12,18,26,27 Arsenic, cadmium, chromium, lead, and mercury have been prioritized by regulatory agencies due to the hazards they present to environmental and human health.

Arsenic
Contaminated water and food are the most common sources of arsenic.10 Inorganic arsenic is highly bioavailable and more toxic than its organic forms.3,10,19,28 Exposure to large doses of arsenic can be fatal.19

Chronic arsenic exposure has been associated with increased mortality and negative health impacts on the kidneys, liver, muscles, and skin, and on pulmonary, cardiovascular, hematological, gastrointestinal, immunological, and neurological systems.3,8 It’s been strongly linked with ischemic heart disease, skin lesions, and lung and bladder cancers.19 It’s also been associated with skin and kidney cancer.20

Arsenic crosses the placenta, and limited research indicates that even low to moderate exposure in pregnancy can adversely affect the fetus, resulting in miscarriage, stillbirth, premature birth, or low birth weight.3,19 Low to moderate exposure in childhood has been associated with negative effects on neurocognitive development, including lower IQ.8,19

Cadmium
Sources of cadmium include occupational exposure (eg, metal machining, welding, painting) and smoking, but diet accounts for most exposure in nonsmokers.23 Once absorbed, a large percentage of cadmium accumulates in the kidneys and liver.29 Cadmium interferes with the absorption of calcium, iron, and zinc.3,15 Cadmium toxicity can lead to anemia and damage to multiple organs and systems, including the kidneys, liver, bones, muscles, and lungs, and the gastrointestinal, reproductive, and nervous systems.3,4,13,15,25

The EPA has designated cadmium as a probable human carcinogen.30 It’s been associated with cancers of the kidney, bladder, gastrointestinal tract, lungs, pancreas, breast, and prostate.3,4,20

Cadmium can inhibit nutrient transfer across the placenta during pregnancy and has been linked with lower infant birth weight and length.15,29 Exposure to cadmium in infancy and early childhood has been associated with lower IQ and a higher incidence of the neurodevelopmental disorder ADHD.8 A cross-sectional study found that school-aged children with the inattentive subtype of ADHD had higher levels of cadmium than children with the hyperactive-impulsive subtype of ADHD or healthy controls.31 Higher cadmium levels in the study were negatively correlated with IQ.31

Chromium
Chromium III, or trivalent chromium, is a trace element found in a variety of foods. Chromium VI, or hexavalent chromium, is a toxic byproduct of industrial processes.5 It’s challenging to differentiate between chromium III and chromium VI because natural reducing agents in many foods and the gastrointestinal tract can convert chromium VI to chromium III.21 Although toxicity can occur from contaminated food or water, the FDA has reported low levels in food samples.3,21

Exposure to elevated levels of the toxic form of chromium can damage the kidneys, skin, and gastrointestinal system. It’s classified as a carcinogen and has been linked with cancers of the lung, larynx, bladder, kidney, testicle, thyroid, and bone.3

Lead
Lead can have negative effects throughout the body. Once absorbed, it’s stored in bones and continues to circulate in the body for decades.32 Lead toxicity can impact heme synthesis, leading to iron deficiency anemia, and may interfere with vitamin D synthesis.22,33 It can damage bones and kidneys and can cause hypertension and damage to cardiovascular, pulmonary, gastrointestinal, hepatic, and neurological systems.3,6,15,21

Lead can pass through the placenta during pregnancy. Lead exposure in pregnancy is associated with several negative outcomes, including miscarriage, elevated blood pressure, preterm birth, fetal growth restriction, and low birth weight.15,26,32,34

While house dust, contaminated soil, and drinking water are the major routes of lead exposure for children, contaminated food remains a concern.10,34 Children absorb higher amounts of ingested lead than adults and are highly sensitive to its neurological effects.26,32 These can include permanent cognitive damage, developmental delays, and attention and behavioral issues.8,15,34 In a cross-sectional study of Taiwanese children with and without ADHD, lead levels were positively correlated with the ADHD symptoms of inattention, hyperactivity, and impulsivity and were negatively correlated with IQ.31 No known level of lead is safe for children’s neurodevelopment, making it difficult for regulatory agencies to set exposure limits.21,26 Lead toxicity can lead to other negative effects in children, including hearing damage, stunted growth, delayed puberty, and kidney damage.8,34

Recent research suggests that adults with chronic low-level lead exposure are also at risk of adverse effects, including decreased cognitive function and CVD.15,35 A prospective study of 14,289 US adults found that even blood lead levels below the CDC’s action level for adults (5 mcg/dL during the study period) were associated with all-cause, cardiovascular, and ischemic heart disease mortality.35

Mercury
Organic forms of mercury are more toxic than inorganic mercury. Humans are mainly exposed to the organic compound methylmercury through food, primarily aquatic foods.3,13,21,36 Methylmercury is easily absorbed and dispersed throughout the body and crosses blood-brain and placental barriers.3,21,37

Mercury toxicity can damage the central nervous system, kidneys, liver, and gastrointestinal tract.3,6 Young children, particularly infants, are more susceptible to central nervous system damage from mercury.13 Prenatal mercury exposure has been linked with birth defects, lower IQ, and neurodevelopmental issues in children.3,8,31,37 Though research is limited, some studies have found that prenatal mercury exposure was associated with poorer cognitive and fine motor function in children and adolescents.13,37

Heavy Metals in Foods
Heavy metal levels in foods vary widely depending on location and sources of contamination. Multiple organizations worldwide regulate heavy metals in the food supply to help protect human and environmental health. Many have set limits, also known as reference values, for human exposure to heavy metals from food and drinking water. Reference values vary by organization and are based on dose-response data from studies of humans and lab animals.21

Assessing the risk of heavy metal ingestion from specific foods is complicated by limited and varying reference values, limited research, and the global food trade.4,12 International reviews have frequently found elevated levels of heavy metals in aquatic foods, vegetables, and fruits.12 One review of 152 studies, including those done in Europe, the Middle East, South America, and North America, with the largest number done in Asia, found that many foods analyzed, some of which were produced in contaminated areas, had heavy metal levels surpassing the study limits (adapted from international reference values) for lead, arsenic, or cadmium.12 While all food groups included samples with elevated heavy metal levels, those most frequently exceeding limits were vegetables and grains, mainly rice.12

An analysis of US and imported rice from Thailand, India, and Italy found that several brown rice and one US white rice sample exceeded Codex Alimentarius Commission arsenic limits.20 Brown rice tends to contain more arsenic and mercury than white rice due to its concentration in the bran.13 According to data from the FDA’s Total Diet Study, which conducts biannual studies of food contaminants in popular foods and food ingredients sold across the United States, rice and rice products like cereals had the highest mean levels of inorganic arsenic.19,21,28

Some imported candies made with tamarind or chili powder contain elevated levels of lead.34,38 Additionally, nonprofit groups have recently alleged that many chocolate bars available for retail sale could result in consumers exceeding California’s Maximum Allowable Dose Levels (MADLs) for lead and cadmium.39 Pending resolution of a lawsuit brought by the nonprofit environmental and social justice group As You Sow against members of the confectionary industry, an expert committee established interim limits for lead and cadmium in cocoa and chocolate products sold in California and made recommendations for manufacturers to reduce heavy metals in their products, including changes in growing and harvesting practices.40 Products with a higher percentage of cocoa have proportionally higher levels of cadmium and lead.18 Research indicates that cadmium is more bioavailable from cocoa products than lead.18

Vegetables, particularly leafy greens; seeds; shellfish; organ meats; nuts; and rice and other grains are also common sources of cadmium.3,4,10,29 The US-sold foods with the highest mean cadmium levels, according to recent Total Diet Study data, were sunflower seeds and spinach.28 Some studies have found higher cadmium levels in vegetarians compared with omnivores, and researchers have suggested that this may be due to higher consumption of plant foods containing cadmium, like spinach, potatoes, and sunflower seeds.4,24

Seafood is the most common food source of mercury, although rice, leafy vegetables, and other foods can also contain mercury, depending on where they’re produced.3,4,13,41 According to Total Diet Study data, the US-sold foods with the highest mean levels of mercury were canned tuna, baked cod, and baked salmon, but none exceeded the FDA’s action level for methylmercury.28 The FDA and the EPA have recommended that children and people who are pregnant or breastfeeding avoid large predatory fish like bigeye tuna, shark, swordfish, marlin, king mackerel, tilefish, and orange roughy due to the risk of elevated mercury levels.42

Infant and Toddler Foods
Heavy metal contamination of baby food is an ongoing concern, particularly since infants and toddlers are highly vulnerable to the adverse effects of heavy metals. Regulatory agencies and nonprofits have reported recent tests detecting lead, arsenic, cadmium, or mercury in many commercial baby and toddler foods.8,43 Infant and toddler foods, including baby food sweet potatoes and teething biscuits, were among the foods with the highest mean lead levels, according to recent Total Diet Study data.28

Although arsenic levels have decreased significantly in US infant cereal and juice over the past decade, arsenic in rice and rice products may still pose risks to the youngest consumers.44 Asian and Hispanic babies may be at higher risk than babies of other ethnicities since they’re more likely to consume rice.44 Rice cereals are a common first food, and studies have found 4.5-fold increases in infants’ levels of toxic inorganic arsenic after weaning.8 Brown rice infant cereals tend to have more arsenic than those made from white rice. In 2020, the FDA finalized its action level for arsenic in infant rice cereal in an effort to moderately reduce the risk of arsenic exposure in children, particularly infants.19,45

However, in a recent study estimating the risk of infants and toddlers’ exposure to heavy metals from a variety of commercial baby foods, both rice-based infant cereals tested exceeded FDA action levels for arsenic.46 Arsenic was determined to present the most significant health risk of the heavy metals, although organic and inorganic arsenic weren’t differentiated.46 The researchers judged that levels of cadmium and mercury in the tested foods did not pose risks, while lead was assessed to present a small risk to young children; lead levels were just over California’s MADL in some products—mostly cereal grains, sweet potatoes, and carrots.46 A study evaluating the food intake of 3,103 children aged 1 to 6 years for lead and cadmium exposure, using Total Diet Study and National Health and Nutrition Examination Survey data, found that many foods commonly consumed by children contained detectable levels of cadmium and lead. Children’s mean estimated lead exposure was below the FDA’s Interim Reference Level (IRL); however, at the 90th percentile, the mean estimated exposure exceeded the IRL.25,27 Children’s mean estimated cadmium exposure exceeded ATSDR limits but not Joint FAO/WHO Expert Committee on Food Additives limits.

Grains, vegetables, and food mixtures, primarily entrees composed of foods from various groups, contributed most to their cadmium exposure, while grains, dairy, fruit, and food mixtures contributed most to their lead exposure; this was partially attributed to the children’s frequent consumption of these foods.25 In 2021, the US House of Representatives Subcommittee on Economic and Consumer Policy reported that four of seven major baby food manufacturers’ products contained concerning levels of arsenic, lead, cadmium, and mercury, while three of the companies hadn’t provided the information requested.8,47 The subcommittee recommended that manufacturers be required to test for and disclose the presence of heavy metals in their products and to replace any ingredients, such as rice or vitamin mixes, identified as sources of contaminants.

It also recommended that the FDA set protective limits for lead, arsenic, cadmium, and mercury in baby foods.47 Nonprofit groups have also advocated for more stringent limits for heavy metals in infant and toddler foods.43,47 In response to concerns, the FDA formed its Closer to Zero action plan focused on reducing infants’ and young children’s exposure to arsenic, lead, cadmium, and mercury in the food supply.48 They have drafted guidance for action levels for lead in juice and processed infant and toddler foods.47,49,50 In collaboration with the USDA, they’ve also been investigating methods to reduce heavy metal absorption by crops.48,51

As of January 2024, the FDA confirmed that elevated levels of lead found in at least 90 people across the United States, mainly babies and young children, were linked to three brands of now-recalled cinnamon applesauce pouches, which reportedly contained imported cinnamon with high levels of lead and chromium.52 This incident demonstrates the challenges associated with regulation of some imported herbs or spices. The FDA’s Center for Food Safety and Applied Nutrition routinely monitors and prevents such products from entering US commerce through sampling at import. However, these surveillance approaches only evaluate a subset of the products imported and may not catch everything. In the “FDA Alert Concerning Certain Cinnamon Products Due to Presence of Elevated Levels of Lead,” the FDA states that it is “the responsibility of the manufacturers and the importers to ensure the safety of the products that enter into the US market.”

Effects of Food Processing and Preparation on Heavy Metal Content
Methods of processing, packaging, preparing, and storing foods can impact heavy metal content.8,14,17,18 Processing rice can lower its arsenic content; instant rice has significantly less arsenic than standard rice.19 Research has also found that rinsing rice prior to cooking it lowered levels of heavy metals, including arsenic, in the range of 28% to 60%, while cooking it in extra water decreased arsenic levels by 40% to 60%, though using water high in arsenic can increase levels.19,20 Rinsing and cooking rice in extra water also lowers levels of enriched nutrients, including iron, folate, thiamin, and niacin, which may be problematic in cases where rice is a critical source of these nutrients.19,20 Cooking may also lower the bioavailability of mercury in seafood; the mercury in canned tuna tends to be less bioavailable than that in raw tuna, likely due to heating during the canning process.41

Processed food ingredients like spices, enzymes, or micronutrients may be contaminated with heavy metals, which can contaminate final products.8 Filtering beverages with processing aids that contain mined minerals like bentonite clay or diatomaceous earth can increase their heavy metal content. Some studies have found increased levels of arsenic, lead, and cadmium in fruit juices, wine, sake, or beer after filtration with bentonite or diatomaceous earth.53 One observational study found higher lead levels in women who drank more than two alcoholic beverages per week, though their levels were well under reference values.24 Storing or consuming food or beverages from containers contaminated with lead, such as lead-glazed ceramic, can also lead to lead exposure.14

Heavy Metals in Spices and Supplements
A number of spices and supplements, particularly imported herbal and traditional remedies, have been identified as potential sources of lead and cadmium.29,54 Many spices are imported from highly polluted areas.55 A recent analysis of 1,496 spice samples from the New York City Department of Health and Mental Hygiene’s investigations found that over 50% of them had detectable lead levels, with over 30% exceeding their guidance level of two parts per million (ppm), with spices purchased abroad having significantly higher levels.54

A North Carolina study based on inspections of the homes of 61 children with elevated lead levels discovered Ayurvedic medicine and spices, including saffron and turmeric, with high levels of lead.55 Research has found that up to one-third of Ayurvedic medicinal products are contaminated with lead, mercury, or arsenic, particularly lead.3,10,55

Nutrition Status and Heavy Metal Toxicity
People’s nutrient status can affect their vulnerability to toxic heavy metals.32 Higher levels of some essential micronutrients appear to protect against lead toxicity; zinc reduces lead absorption in the gastrointestinal tract.32 In pregnancy, higher intakes of calcium have been associated with lower blood lead levels.26 Inadequate levels of calcium, iron, and zinc can increase lead absorption and have been linked with lead toxicity, particularly in children.26,32 A study of 310 Pakistani children aged 1 through 10 found that lower blood levels of calcium, iron, and zinc were associated with higher lead levels and that malnourished children had lower levels of essential micronutrients and higher levels of lead than well-nourished children.32

Susceptibility to cadmium’s effects can also be influenced by nutrient status. Having adequate stores of calcium, iron, and zinc can lower cadmium absorption from food, and zinc protects against oxidative stress and bone damage from cadmium.29 Conversely, deficiencies of protein, calcium, and vitamin D can increase susceptibility to bone damage from cadmium.29

Following a gluten-free diet may be a risk factor for heavy metal exposure, possibly due to a lower intake of essential minerals, including iron and zinc.56 In a cross-sectional study based on National Health and Nutrition Examination Survey data from 2009 to 2012, individuals following gluten-free diets had significantly higher blood levels of mercury, lead, and cadmium and urine levels of arsenic than those not restricting gluten. Researchers theorized that higher intakes of fish and rice-based foods by those following gluten-free diets may also contribute to increased heavy metal levels, although the study didn’t analyze specific dietary intake.56

Recommendations for RDs: Putting It Into Practice
Heavy metal contamination of food can endanger public health, particularly during vulnerable life stages, including pregnancy, infancy, and childhood. Exposure to toxic heavy metals can lead to a host of adverse effects, such as essential nutrient depletion, damage to multiple organs and body systems, and impairment of neurodevelopment and cognition. As food and nutrition professionals, RDs are uniquely positioned to advocate effectively for reducing harmful heavy metals in the food supply in collaboration with other health experts, nonprofit groups, and lawmakers.

RDs can also help clients reduce their risk of heavy metal toxicity by assessing for adequate levels of essential nutrients, particularly iron, calcium, and zinc, encouraging them to consume a variety of nutrient-rich foods, and avoiding or limiting products that tend to be high in heavy metals. RDs should encourage caregivers of infants and toddlers to offer a variety of cereal grains and limit fruit juices and processed foods made with rice ingredients.44,46,57,58 They can also advise clients on food preparation techniques that may reduce heavy metals, such as rinsing rice or cooking it in extra water.8,20 Thoroughly washing produce, removing the outer layers of leafy vegetables, and peeling root vegetables may also lower heavy metal exposure.14

RDs can play a critical role in reducing the adverse environmental and public health effects of heavy metals by advocating for more research and regulation. They can also assist individuals with optimizing their nutrition status and intake to limit heavy metal exposure.

— Sara Chatfield, MPH, RDN, LDN, is a Chicago-based freelance nutrition writer who has practiced dietetics in clinical and community settings.

Learning Objectives
After completing this continuing education course, nutrition professionals should be better able to:
1. Name five heavy metal contaminants found in food.
2. List four sources of heavy metal contamination of food.
3. Detail at least six potential health complications of heavy metal ingestion.
4. Name eight organizations working to limit heavy metals in food sources.
5. Describe strategies for limiting the ingestion of heavy metals.

Examination
1. The Food and Nutrition Board has set adequate intakes for the following heavy metal, which also has a toxic form:
a. Arsenic
b. Chromium
c. Mercury
d. Cadmium

2. What is a common anthropogenic source of heavy metals in the environment?
a. Erosion
b. Forest fires
c. Volcanic ash
d. Agricultural waste

3. In a Chinese study of 22 types of vegetables grown in contaminated soil, which group of vegetables absorbed the greatest concentration of heavy metals?
a. Root vegetables like carrots and sweet potatoes
b. Melon-type vegetables like cucumbers and pumpkin
c. Leafy vegetables like cabbage and spinach
d. Caitai, a “stalk” vegetable

4. In 2020, the FDA reduced its action level for the following heavy metal often found to be elevated in infant rice cereal:
a. Nickel
b. Chromium
c. Arsenic
d. Zinc

5. The US Environmental Protection Agency and the FDA have advised children and people who are pregnant or breastfeeding to avoid consuming large predatory fish due to the risk of ingestion of which heavy metal?
a. Mercury
b. Chromium VI
c. Arsenic
d. Lead

6. As part of their Closer to Zero action plan, the FDA has recently drafted guidance for action levels for lead in which foods?
a. Chocolate and baked goods
b. Fish and shellfish
c. Milk and infant formula
d. Juice and processed infant and toddler foods

7. Research has found that up to this amount of Ayurvedic medicinal products are contaminated with heavy metals, especially lead:
a. One-half
b. One-third
c. One-fifth
d. One-eighth

8. Having adequate levels of calcium, iron, and zinc has been associated with a reduced risk of toxicity from which heavy metal(s)?
a. Chromium III and chromium VI
b. Methylmercury
c. Lead and cadmium
d. Arsenic

9. What strategy can cut down on arsenic ingestion from rice?
a. Choosing brown rice
b. Purchasing fortified rice
c. Purchasing organic rice
d. Rinsing rice prior to cooking

10. What strategy is recommended to help reduce heavy metal ingestion from produce?
a. Avoiding leafy vegetables
b. Avoiding nonorganic produce
c. Thorough washing
d. Leaving the peel on root vegetables

References
1. Rai PK, Lee SS, Zhang M, Tsang YF, Kim KH. Heavy metals in food crops: health risks, fate, mechanisms, and management. Environ Int. 2019;125:365-385.

2. Rezapour S, Siavash Moghaddam S, Nouri A, Khosravi Aqdam K. Urbanization influences the distribution, enrichment, and ecological health risk of heavy metals in croplands. Sci Rep. 2022;12(1):3868.

3. Balali-Mood M, Naseri K, Tahergorabi Z, Khazdair MR, Sadeghi M. Toxic mechanisms of five heavy metals: mercury, lead, chromium, cadmium, and arsenic. Front Pharmacol. 2021;12:643972.

4. Witkowska D, Słowik J, Chilicka K. Heavy metals and human health: possible exposure pathways and the competition for protein binding sites. Molecules. 2021;26(19):6060.

5. Chromium: fact sheet for health professionals. National Institutes of Health website. https://ods.od.nih.gov/factsheets/chromium-HealthProfessional/. Updated June 2, 2022. Accessed January 20, 2023.

6. Gaur VK, Sharma P, Gaur P, et al. Sustainable mitigation of heavy metals from effluents: toxicity and fate with recent technological advancements. Bioengineered. 2021;12(1):7297-7313.

7. Briffa J, Sinagra E, Blundell R. Heavy metal pollution in the environment and their toxicological effects on humans. Heliyon. 2020;6(9):e04691.

8. Bair EC. A narrative review of toxic heavy metal content of infant and toddler foods and evaluation of United States policy. Front Nutr. 2022;9:919913.

9. Kumar V, Parihar RD, Sharma A, et al. Global evaluation of heavy metal content in surface water bodies: a meta-analysis using heavy metal pollution indices and multivariate statistical analyses. Chemosphere. 2019;236:124364.

10. Fisher RM, Gupta V. Heavy metals. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2022:1-10. https://www.ncbi.nlm.nih.gov/books/NBK557806/.

11. Uddin MM, Zakeel MCM, Zavahir JS, Marikar FMMT, Jahan I. Heavy metal accumulation in rice and aquatic plants used as human food: a general review. Toxics. 2021;9(12):360.

12. Collado-López S, Betanzos-Robledo L, Téllez-Rojo MM, et al. Heavy metals in unprocessed or minimally processed foods consumed by humans worldwide: a scoping review. Int J Environ Res Public Health. 2022;19(14):8651.

13. Hutcherson EK, Kumar DA, Palmeiri JR, Wilson ML. Mercury exposure and potential risks from rice-based infant foods in infants: a literature review. SM J Food Nutri Disord. 2020;5(8).

14. Food and Agriculture Organization of the United Nations; World Health Organization; Codex Alimentarius International Food Standards. Code of Practice for the Prevention and Reduction of Lead Contamination in Foods. Revised 2021. Accessed January 20, 2023.

15. Alengebawy A, Abdelkhalek ST, Qureshi SR, Wang MQ. Heavy metals and pesticides toxicity in agricultural soil and plants: ecological risks and human health implications. Toxics. 2021;9(3):42.

16. Zhou H, Yang WT, Zhou X, et al. Accumulation of heavy metals in vegetable species planted in contaminated soils and the health risk assessment. Int J Environ Res Public Health. 2016;13(3):289.

17. Callen C, Bhatia J, Czerkies L, Klish WJ, Gray GM. Challenges and considerations when balancing the risks of contaminants with the benefits of fruits and vegetables for infants and toddlers. Nutrients. 2018;10(11):1572.

18. Anyimah-Ackah E, Ofosu IW, Lutterodt HE, Darko G. Exposures and risks of arsenic, cadmium, lead, and mercury in cocoa beans and cocoa-based foods: a systematic review. Food Qual Saf. 2019;3(1):1-8.

19. Arsenic in rice and rice products risk assessment. US Food & Drug Administration website. https://www.fda.gov/food/cfsan-risk-safety-assessments/arsenic-rice-and-rice-products-risk-assessment. Updated August 5, 2020. Accessed January 20, 2023.

20. TatahMentan M, Nyachoti S, Scott L, et al. Toxic and essential elements in rice and other grains from the United States and other countries. Int J Environ Res Public Health. 2020;17(21):8128.

21. Wong C, Roberts SM, Saab IN. Review of regulatory reference values and background levels for heavy metals in the human diet. Regul Toxicol Pharmacol. 2022;130:105122.

22. Słota M, Wąsik M, Stołtny T, Machoń-Grecka A, Kasperczyk S. Effects of environmental and occupational lead toxicity and its association with iron metabolism. Toxicol Appl Pharmacol. 2022;434:115794.

23. Park SJ, Lee JH, Woo SJ, Kang SW, Park KH; Epidemiologic Survey Committee of Korean Ophthalmologic Society. Five heavy metallic elements and age-related macular degeneration: Korean National Health and Nutrition Examination Survey, 2008-2011. Ophthalmology. 2015;122(1):129-137.

24. Fløtre CH, Varsi K, Helm T, Bolann B, Bjørke-Monsen AL. Predictors of mercury, lead, cadmium and antimony status in Norwegian never-pregnant women of fertile age. PLoS One. 2017;12(12):e0189169.

25. Spungen JH. Children's exposures to lead and cadmium: FDA total diet study 2014-16. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2019;36(6):893-903.

26. Flannery BM, Dolan LC, Hoffman-Pennesi D, et al. U.S. Food and Drug Administration's interim reference levels for dietary lead exposure in children and women of childbearing age. Regul Toxicol Pharmacol. 2020;110:104516.

27. Flannery BM, Middleton KB. Updated interim reference levels for dietary lead to support FDA's Closer to Zero action plan. Regul Toxicol Pharmacol. 2022;133:105202.

28. FDA Total Diet Study (TDS): results. US Food & Drug Administration website. https://www.fda.gov/food/fda-total-diet-study-tds/fda-total-diet-study-tds-results. Updated December 20, 2023. Accessed January 20, 2023.

29. Schaefer HR, Dennis S, Fitzpatrick S. Cadmium: mitigation strategies to reduce dietary exposure. J Food Sci. 2020;85(2):260-267.

30. Cadmium. United States Environmental Protection Agency IRIS website. https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=141. Updated July 28, 2017. Accessed January 20, 2023.

31. Lee MJ, Chou MC, Chou WJ, et al. Heavy metals' effect on susceptibility to attention-deficit/hyperactivity disorder: implication of lead, cadmium, and antimony. Int J Environ Res Public Health. 2018;15(6):1221.

32. Talpur S, Afridi HI, Kazi TG, Talpur FN. Interaction of lead with calcium, iron, and zinc in the biological samples of malnourished children. Biol Trace Elem Res. 2018;183(2):209-217.

33. Rahman A, Al-Awadi AA, Khan KM. Lead affects Vitamin D metabolism in rats. Nutrients. 2018;10(3):264.

34. Council on Environmental Health. Prevention of childhood lead toxicity. Pediatrics. 2016;138(1):e20161493.

35. Lanphear BP, Rauch S, Auinger P, Allen RW, Hornung RW. Low-level lead exposure and mortality in US adults: a population-based cohort study. Lancet Public Health. 2018;3(4):e177-e184.

36. Mercury and health. World Health Organization website. https://www.who.int/news-room/fact-sheets/detail/mercury-and-health. Updated March 31, 2017. Accessed March 29, 2023.

37. Jacobson JL, Muckle G, Ayotte P, Dewailly É, Jacobson SW. Relation of prenatal methylmercury exposure from environmental sources to childhood IQ. Environ Health Perspect. 2015;123(8):827-833.

38. Lead in foods, cosmetics, and medicines. Centers for Disease Control and Prevention website. https://www.cdc.gov/nceh/lead/prevention/sources/foods-cosmetics-medicines.htm. Updated May 17, 2022. Accessed March 13, 2023.

39. Lead and cadmium could be in your dark chocolate. Consumer Reports website. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/. Published December 15, 2022. Accessed January 20, 2023.

40. Expert investigation related to cocoa and chocolate products. As You Sow website. https://www.asyousow.org/reports/expert-investigation-related-to-cocoa-and-chocolate. Published March 28, 2022. Accessed January 20, 2023.

41. Bradley MA, Barst BD, Basu N. A review of mercury bioavailability in humans and fish. Int J Environ Res Public Health. 2017;14(2):169.

42. Advice about eating fish. US Food & Drug Administration website. https://www.fda.gov/food/consumers/advice-about-eating-fish. Updated September 28, 2022. Accessed January 20, 2023.

43. What’s in my baby’s food? Healthy Babies, Bright Futures website. https://www.healthybabyfood.org/sites/healthybabyfoods.org/files/2019-10/BabyFoodReport_FULLREPORT_ENGLISH_R5b.pdf. Published October 2019. Accessed March 13, 2023.

44. Report: is homemade baby food better? Healthy Babies Bright Futures website. https://hbbf.org/resource/2022-12/report-homemade-baby-food-better. Published September 30, 2022. Accessed January 20, 2023.

45. FDA in brief: FDA takes action to limit inorganic arsenic levels in infant rice cereal. US Food & Drug Administration website. https://www.fda.gov/news-events/fda-newsroom/fda-brief-fda-takes-action-limit-inorganic-arsenic-levels-infant-rice-cereal. Updated August 5, 2020.

46. Parker GH, Gillie CE, Miller JV, Badger DE, Kreider ML. Human health risk assessment of arsenic, cadmium, lead, and mercury ingestion from baby foods. Toxicol Rep. 2022;9:238-249.

47. US House of Representatives Subcommittee on Economic and Consumer Policy. Baby foods are tainted with dangerous levels of arsenic, lead, cadmium, and mercury. https://oversight.house.gov/news/press-releases/oversight-subcommittee-staff-report-reveals-top-baby-foods-contain-dangerous. Published February 4, 2021. Accessed December 13, 2022.

48. Closer to Zero: reducing childhood exposure to contaminants from foods. US Food & Drug Administration website. https://www.fda.gov/food/environmental-contaminants-food/closer-zero-action-plan-baby-foods. Updated June 7, 2024. Accessed January 20, 2023.

49. US Food & Drug Administration. Action levels for lead in juice: guidance for industry. https://www.fda.gov/media/157949/download. Published April 2022. Accessed January 20, 2023.

50. US Food & Drug Administration. Action levels for lead in food intended for babies and young children: draft guidance for industry. https://www.fda.gov/media/164684/download. Published January 2023. Accessed March 13, 2023.

51. Closer to Zero: partnership to protect our food. US Department of Agriculture website. https://www.usda.gov/media/blog/2022/01/21/closer-zero-partnership-protect-our-food#:~:text=The%20Food%20Safety%20and%20Inspection,substance%20are%20detected%20in%20food. Updated January 31, 2022. Accessed January 20, 2023.

52. Post-incident response activities: elevated lead and chromium levels in cinnamon applesauce pouches. US Food & Drug Administration website. https://www.fda.gov/food/outbreaks-foodborne-illness/post-incident-response-activities-elevated-lead-and-chromium-levels-cinnamon-applesauce-pouches. Published August 16, 2024. Accessed August 20, 2024.

53. Redan BW. Processing aids in food and beverage manufacturing: potential source of elemental and trace metal contaminants. J Agric Food Chem. 2020;68(46):13001-13007.

54. Hore P, Alex-Oni K, Sedlar S, Nagin D. A spoonful of lead: a 10-year look at spices as a potential source of lead exposure. J Public Health Manag Pract. 2019;25 Suppl 1, Lead Poisoning Prevention:S63-S70.

55. Angelon-Gaetz KA, Klaus C, Chaudhry EA, Bean DK. Lead in spices, herbal remedies, and ceremonial powders sampled from home investigations for children with elevated blood lead levels - North Carolina, 2011-2018. MMWR Morb Mortal Wkly Rep. 2018;67(46):1290-1294.

56. Raehsler SL, Choung RS, Marietta EV, Murray JA. Accumulation of heavy metals in people on a gluten-free diet. Clin Gastroenterol Hepatol. 2018;16(2):244-251.

57. Heavy metals in baby food. American Academy of Pediatrics website. https://www.healthychildren.org/English/ages-stages/baby/feeding-nutrition/Pages/Metals-in-Baby-Food.aspx. Updated August 12, 2022. Accessed January 20, 2023.

58. FDA response to question about levels of toxic elements in baby food, following Congressional report. US Food & Drug Administration website. https://www.fda.gov/food/cfsan-constituent-updates/fda-response-questions-about-levels-toxic-elements-baby-food-following-congressional-report. Updated February 16, 2021. Accessed January 20, 2023.

Table 2 References
1. Collado-López S, Betanzos-Robledo L, Téllez-Rojo MM, et al. Heavy metals in unprocessed or minimally processed foods consumed by humans worldwide: a scoping review. Int J Environ Res Public Health. 2022;19(14):8651.

2. Wong C, Roberts SM, Saab IN. Review of regulatory reference values and background levels for heavy metals in the human diet. Regul Toxicol Pharmacol. 2022;130:105122.

3. Food safety and quality. Food and Agriculture Organization of the United Nations website. https://www.fao.org/food/food-safety-quality/scientific-advice/jecfa/jecfa-additives/about/en/. Updated 2023. Accessed January 20, 2023.

4. Basic information about the Integrated Risk Information System. United States Environmental Protection Agency website. https://www.epa.gov/iris/basic-information-about-integrated-risk-information-system. Updated November 9, 2023. Accessed January 20, 2023.

5. Agency for Toxic Substances and Disease Registry website. https://www.atsdr.cdc.gov/. Updated February 28, 2023. Accessed March 13, 2023.

6. HHS agencies and offices. US Department of Health & Human Services website. https://www.hhs.gov/about/agencies/hhs-agencies-and-offices/index.html. Updated March 12, 2024. Accessed March 13, 2023.

7. Minimal Risk Levels (MRLs) for hazardous substances. Agency for Toxic Substances and Disease Registry website. https://wwwn.cdc.gov/TSP/MRLS/mrlsListing.aspx. Updated May 3, 2024. Accessed March 15, 2023.

8. FDA working to protect consumers from toxic metals in foods. US Food & Drug Administration website. https://www.fda.gov/food/cfsan-constituent-updates/fda-working-protect-consumers-toxic-metals-foods. Updated April 11, 2018. Accessed March 13, 2023.

9. Flannery BM, Dolan LC, Hoffman-Pennesi D, et al. US Food and Drug Administration's interim reference levels for dietary lead exposure in children and women of childbearing age. Regul Toxicol Pharmacol. 2020;110:104516.

10. Contaminants in the food chain. European Food Safety Authority website. https://www.efsa.europa.eu/en/science/scientific-committee-and-panels/contam. Updated August 29, 2022. Accessed January 20, 2023.

11. Food safety: what the Commission is doing. European Commission website. https://commission.europa.eu/topics/food-safety_en. Accessed January 20, 2023.

12. Statement on tolerable weekly intake for cadmium. European Food Safety Authority website. https://www.efsa.europa.eu/en/efsajournal/pub/1975. Updated 2011. Accessed May 5, 2023.

13. Closer to Zero: partnership to protect our food. US Department of Agriculture website. https://www.usda.gov/media/blog/2022/01/21/closer-zero-partnership-protect-our-food#:~:text=The%20Food%20Safety%20and%20Inspection,substance%20are%20detected%20in%20food. Updated January 21, 2022. Accessed January 20, 2023.

14. Proposition 65. California Office of Environmental Health Hazard Assessment website. https://oehha.ca.gov/proposition-65. Updated 2023. Accessed January 20, 2023.

15. Proposition 65 No Significant Risk Levels (NSRLs) and Maximum Allowable Dose Levels (MADLs). California Office of Environmental Health Hazard Assessment website. https://oehha.ca.gov/proposition-65/general-info/current-proposition-65-no-significant-risk-levels-nsrls-maximum. Updated October 27, 2023. Accessed March 15, 2023.

Table 4 References
1. Evaluations of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). CADMIUM. World Health Organization website. https://apps.who.int/food-additives-contaminants-jecfa-database/Home/Chemical/1376#:~:text=below%20the%20PTMI.-,Intake%3A,%CE%BCg%2Fkg%20bw%2Fmonth. Updated 2021. Accessed March 15, 2023.

2. Evaluations of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). METHYLMERCURY. World Health Organization website. https://apps.who.int/food-additives-contaminants-jecfa-database/Home/Chemical/3083. Updated 2021. Accessed March 15, 2023.

3. Flannery BM, Dolan LC, Hoffman-Pennesi D, et al. U.S. Food and Drug Administration's interim reference levels for dietary lead exposure in children and women of childbearing age. Regul Toxicol Pharmacol. 2020;110:104516.

4. Arsenic compounds. US Environmental Protection Agency website. https://www.epa.gov/sites/default/files/2021-04/documents/arsenic_april_2021.pdf. Updated April 2021. Accessed March 15, 2023.

5. Cadmium compounds. US Environmental Protection Agency website. https://www.epa.gov/sites/default/files/2016-09/documents/cadmium-compounds.pdf. Updated January 2000. Accessed March 15, 2023.

6. Chromium compounds. US Environmental Protection Agency website. https://www.epa.gov/sites/default/files/2016-09/documents/chromium-compounds.pdf. Updated January 2000. Accessed March 15, 2023.

7. Methylmercury (MeHg). US Environmental Protection Agency website. https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=73. Updated July 28, 2017. Accessed March 15, 2023.

8. Minimal Risk Levels (MRLs) for hazardous substances. Agency for Toxic Substances and Disease Registry website. https://wwwn.cdc.gov/TSP/MRLS/mrlsListing.aspx. Updated May 3, 2024. Accessed March 15, 2023.

9. Faroon O, Ashizawa A, Wright S, et al. Toxicological Profile for Cadmium. Atlanta, GA: Agency for Toxic Substances and Disease Registry (US); 2012. https://www.ncbi.nlm.nih.gov/books/NBK158837/#S20.

10. Proposition 65 No Significant Risk Levels (NSRLs) and Maximum Allowable Dose Levels (MADLs). California Office of Environmental Health Hazard Assessment website. https://oehha.ca.gov/proposition-65/general-info/current-proposition-65-no-significant-risk-levels-nsrls-maximum. Updated 2023. Accessed March 15, 2023.

11. Statement on tolerable weekly intake for cadmium. European Food Safety Authority website. https://www.efsa.europa.eu/en/efsajournal/pub/1975. Updated 2011. Accessed May 5, 2023.

12. Scientific opinion on the risk for public health related to the presence of mercury and methylmercury in food. European Food Safety Authority website. https://www.efsa.europa.eu/en/efsajournal/pub/2985. Updated April 10, 2018. Accessed May 5, 2023.

Table 5 References
1. CPG sec 540.600 fish, shellfish, crustaceans and other aquatic animals — fresh, frozen or processed — methyl mercury. US Food & Drug Administration website. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cpg-sec-540600-fish-shellfish-crustaceans-and-other-aquatic-animals-fresh-frozen-or-processed-methyl. Updated August 24, 2018. Accessed March 15, 2023.

2. Guidance for industry: lead in candy likely to be consumed frequently by small children. US Food & Drug Administration website. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-lead-candy-likely-be-consumed-frequently-small-children. Updated September 20, 2018. Accessed January 20, 2023.

3. FDA in brief: FDA takes action to limit inorganic arsenic levels in infant rice cereal. US Food & Drug Administration website. https://www.fda.gov/news-events/fda-newsroom/fda-brief-fda-takes-action-limit-inorganic-arsenic-levels-infant-rice-cereal. Updated August 5, 2020. Accessed March 15, 2023.

4. Action levels for lead in food intended for babies and young children: draft guidance for industry. US Food & Drug Administration website. https://www.fda.gov/media/164684/download. Published January 2023. Accessed March 13, 2023.

5. FDA issues final guidance to industry on action level for inorganic arsenic in apple juice. US Food & Drug Administration website. https://www.fda.gov/food/cfsan-constituent-updates/fda-issues-final-guidance-industry-action-level-inorganic-arsenic-apple-juice. Updated June 1, 2023. Accessed June 14, 2023.

6. Draft guidance for industry: action levels for lead in juice. US Food & Drug Administration website. https://www.fda.gov/media/157949/download. Published April 2022. Accessed January 20, 2023.

7. Document 32006R1881: Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs. EUR-Lex website. https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32006R1881. Updated January 1, 2023. Accessed March 15, 2023.

8. Document 32021R1323: Commission Regulation (EU) 2021/1323 of 10 August 2021 amending Regulation (EC) No 1881/2006 as regards maximum levels of cadmium in certain foodstuffs. EUR-Lex website. https://eur-lex.europa.eu/eli/reg/2021/1323/oj. Updated August 10, 2021. Accessed March 15, 2023.

9. Toxins in chocolate. As You Sow website. https://www.asyousow.org/our-work/environmental-health/toxic-enforcement/lead-and-cadmium-in-food/lead-and-cadmium-in-food-faqs/#faq7. Updated 2023. Accessed March 29, 2023.