Although it may sound alarming, metals in our food supply is nothing new. Metals are natural elements found in Earth’s crust, and they often make their way into plant-based foods through irrigation and soil and dust particles, frequently with some “help” from humans (e.g. through sediments from smoking, the use of lead pipes in construction, some forms of paint, and other materials). In the field of food and nutrition, trace elements, or “trace metals,” can actually be beneficial to human health across the life stages. However, with news about “toxic metals” in our food on the rise, we may be feeling concerned about our health and well-being—and the well-being of those we provide food for every day.
The good news is that emerging technologies are allowing scientists to test for metals with better and better sensitivity. These findings have advanced federal policies, nutritional guidance, and national health goals. For example, the U.S. Department of Health and Human Services’ Healthy People 2030 General Environment Health lays out objectives for reducing specific metals, as does the U.S. Food and Drug Administration (FDA)’s Closer to Zero: Action Plan for Baby Foods document that was shared in 2020. Since 1961, the FDA has tested and monitors metals and other elements in our food through the Total Diet Study. These efforts are overseen by the FDA’s Toxic Elements Working Group, which aims to reduce consumer exposure to toxic elements in food, dietary supplements, and cosmetics. “Toxic” elements in this context include, but are not limited to, cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As), all of which you can find more information about below. Lastly, current best-practice manufacturing guidelines during food processing, as well as the documentation of land-use history and water-quality at the farming level of our food supply chain, also help maintain our safe food supply.
The goal of the FDA initiative Closer to Zero: Action Plan for Baby Foods is to reduce babies’ and young children’s exposure to toxic elements such as arsenic, cadmium, lead, and mercury in widely manufactured baby foods. This plan is a science-based, multi-phase, and iterative approach to ensure improvement over time in continually reducing toxic elements in foods. This ongoing monitoring includes evaluating the current science, proposing and finalizing courses of action, and consulting with multiple stakeholders over the next several years and beyond.
Arsenic is a naturally occurring element that is introduced into soil, ground sediment, and water through agricultural and industrial practices. Arsenic occurs in both organic and inorganic forms; the inorganic form is more pressing to public health. Inorganic arsenic is a carcinogen, and exposure to low levels of inorganic arsenic over time can cause skin discoloration and warts to appear, as well as skin redness and swelling. Current regulations stipulate that arsenic in drinking water and apple juice should not exceed 10 parts per billion (ppb) and arsenic in infant rice cereals should not exceed 100 ppb. Historically, inorganic arsenic is associated with rice and rice products, seaweed, and some fruit juices. The best way to avoid overconsumption of these products is to eat a balanced diet with a variety of foods from each food group.
Cadmium is a naturally occuring element that is introduced into soil, water, and air through the mining industry, the processing of household wastes, and the burning of coal. Cadmium can also be absorbed by plants from their environment. The relationship between this metal and public health is that breathing high levels of cadmium can damage the lungs, and consuming cadmium-contaminated foods can irritate the stomach and cause diarrhea and vomiting. In addition, cadmium is a probable carcinogen. Currently, bottled drinking water should not exceed 5 ppb of cadmium. Historically, cadmium is associated with leafy vegetables, grains, and legumes, and eating a balanced diet with a variety of foods from each food group is the best way to avoid overconsumption of this element.
Lead is a naturally occurring element that can contaminate soil and water and historically has been used widely in household and industrial paint, water pipes, caulking, and ceramics. Lead can also be found in older homes and buildings in which food has been prepared or manufactured. Lead is a public health concern—any amount of lead exposure negatively affects human health. Lead also is a probable carcinogen, but primarily targets the nervous systems of youth and adults. Children are more vulnerable to lead poisoning, and lead toxicity can lead to decreased mental development and physical growth. Lead poisoning can also lead to brain damage and premature birth among pregnant women. Currently, lead in drinking water should not to exceed 5 ppb, apple juice should not exceed 50 ppb, and in candy likely to be consumed by young children should not exceed 0.1 ppm. Historically, lead has been associated with imported candies and fruit juices. As with other toxic elements, eating a balanced diet with a variety of foods from each food group is one of the best ways to avoid overconsumption of lead—in addition to being aware of common lead carriers. For example, if you are growing your own edible garden, you should get your soil and water tested; and if you live in a home constructed before 1978, you should have it tested for lead as well.
Mercury is a naturally occurring element that is found in air, water, and certain foods at low levels. Mercury can occur in both inorganic and organic forms and is well-known as a public health concern. Inorganic mercury consumed in large amounts can cause irritation and corrosion of the digestive system. Exposure to mercury over a long period of time can also lead to neurological disturbances, rashes, and kidney abnormalities, as well as other health ailments. Methylmercury, when consumed in large amounts in its organic form over weeks or months, can cause nervous system damage. In addition, infants born to women with methylmercury poisoning have incurred developmental abnormalities and cerebral palsy.
A word about fish: Mercury is commonly associated with eating fish. However, mercury is not found at unsafe levels in all types of fish, and it’s important to know the types of fish that are nutritious and safe to eat. In 2022, the FDA and EPA revised their guidance regarding eating fish. The updated information is targeted to help those who are pregnant or breastfeeding or who might become pregnant as well as parents and caregivers who are feeding their children fish. In addition to advising on the nutritional benefits of eating fish, the new guidelines include “choosing a variety of fish that are lower in mercury.”
How To Reduce Toxic Metals in Your Diet
- Know that both organic and conventionally grown produce and grains can absorb toxic metals.
- Eat a balanced diet with a variety of foods from each food group (fruit, vegetable, protein, grain and dairy). Nutritional variety will not only increase the diverse vitamins and minerals you take in; it will also mitigate the risks of consuming deleterious metals that may arise from overconsuming a particular food or food group over time.
- Use food-grade cookware, which can reduce the introduction of toxic metals into foods prepared at home.
In addition to reducing your own potential exposure to toxic metals, be sure to educate your family and friends on the common sources of these health hazards by sharing resources (like the U.S. government’s “Closer to Zero: Action Plan for Baby Food” document) and encouraging people in your social networks to make informed, healthful decisions when it comes to reducing toxic metals in our diets.
This article was written by Shauna Henley, PhD.
Additional Resources and Infant-to-Toddler Guidance on Metals in Foods
- FDA: Metals and Your Food
- USDA WIC Resources: Metals in Baby Food
- IFIC: Infant and Toddler Feeding Guide
Agency for Toxic Substances and Disease Registry (ASTDR). 2020. Lead ToxFAQs. Division of Toxicology and Human Health Sciences, U.S. Department of Health and Human Services. 2020.
Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Cadmium. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. 2012.
“Bottled Water Everywhere: Keeping it Safe”, U.S. Food and Drug Administration, 2022.
“Chemical Contaminant Rules”, U.S. Environmental Protection Agency, 2021.
“Dietary Guidelines for Americans: 2020 – 2025″, U.S. Department of Agriculture, 2020.
“Inorganic Arsenic in Rice Cereal for Infants: Action Level Guidance for Industry” Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, 2020.
Toxicological Profile for Mercury. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, 2022.