Heavy metals, such as arsenic, lead, cadmium, chromium, and mercury, are naturally found in the environment, including water, soil, and the atmosphere. Authority health organizations report tolerable limits of heavy metal exposures because heavy metal accumulation may cause long-term health problems. In this article, you'll find the list of foods likely to contain heavy metals, the risks associated with consuming them, and tips to minimize heavy metal exposure.
When heavy metals are ingested, they bind to enzymes and proteins, affecting their functions and resulting in dysfunction and health problems. To minimize risk to public health, authority health organizations, including the Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO), put limits on the heavy metal content of foods. Heavy metals include but are not limited to:
Arsenic is a heavy metal known as the king of poison. It's contaminated from natural and industrial sources such as volcanic ash, geothermal springs, herbicides, pesticides, and electronics in the forms of arsenite and arsenate.
Long-term arsenic exposure has been associated with cell damage, skin disorders, and increased vascular permeability, which may cause cardiovascular problems.
If you use well water, testing arsenic levels of water in the spring is recommended; the arsenic levels should be below 10 parts per billion (.01 milligram per liter) according to the federal standard for safe drinking water.
Lead is one of the highly toxic heavy metals. It's been associated with impaired cognitive development and lower IQs in children. Lead positioning is still a concern in developing countries.
High lead levels have been reported in some candies, cosmetics, and herbs used in traditional medicine, such as Ba-baw-san, Daw Tway, Greta, and Azarcon.
Mercury is used in mining, producing light bulbs, fungicides to protect plants, cosmetics, dental amalgams, etc. Chronic mercury exposure has been associated with neurocognitive alterations, such as loss of memory and cognitive abilities, irritability, sleep problems, and kidney abnormalities. Contamination with mercury has been reported in fish and seafood.
Cadmium is also accepted as a cancer-causing agent, which is used in mining, plastics, batteries, pigments, and cigarettes. Food and water contain low levels of cadmium.
People smoking are exposed to cadmium. Accumulation of low levels of cadmium exposure, such as smoking, can cause fragile bones and kidney diseases. High amounts of cadmium exposure can cause lung damage.
Nickel is naturally found in soil and water. Nickel exposure is associated with contact dermatitis. Although nickel may be found in foods, such as cereals, chocolate, teas, and legumes, it doesn't pose a higher toxicity risk due to low absorption.
Also, tobacco smoke contains nickel. Toxicity of nickel is generally caused by exposure to nickel in the workplace since it has industrial uses.
Heavy metals in common foods
Heavy metals are naturally found in the environment, but their contamination has increased with industrialization. Since heavy metals don't dissolve, they accumulate in the environment and pass through to humans with foods, drinks, and chemicals.
Fish and seafood
Fish and seafood, a source of omega-3 fatty acids, contain methylmercury. Although fish and seafood have heavy metals, health organizations, such as the European Food Safety Authority (EFSA) and the FDA, advise eating fish species containing lower levels of methylmercury because the health benefits of those foods outweigh the potential hazards.
Fish and seafood containing high methylmercury include but are not limited to:
- King mackerel
- Orange roughy
Fish and seafood containing lower methylmercury include but are not limited to:
- Trout, fresh water
- Black sea bass
In June 2023, the FDA updated the warning about arsenic content in apple juices. The agency reported some products on the market exceed the acceptable limit of 10 ppb arsenic.
In a 2016 report by the FDA on arsenic in rice and rice products, white rice, brown rice, infant dry white rice cereal, and infant dry brown rice cereal contain 90–120 ppb of inorganic arsenic (more toxic form) on average.
Chocolate also contains heavy metals such as nickel and cadmium, whose amounts change based on where cocoa is grown. However, the WHO concluded that cadmium exposure by cacao is minimal, even if cocoa consumption is high.
Meat and meat products
When animals are fed contaminated animal foods, meat contains heavy metals. Amounts can change from country to country; heavy metal content is probably higher in more industrialized places.
Different concentrations of heavy metals, including cadmium, lead, mercury, and arsenic, have been reported in various meat and meat products, such as beef, pork, bacon, ham, sausage, poultry, and so on.
Fruits and vegetables
Since heavy metals are found in soil and water, it's impossible to eliminate their presence in fruits and vegetables. The composition and concentration of the presence of heavy metals can change from region to region. For example, lettuce from the Egyptian sample was reported to be high in nickel, U.S. samples were high in arsenic, and Romania's was high in zinc.
A study showed that milk from Holstein Friesian cows contained higher lead, cadmium, and copper concentrations compared to milk from Simmental cows.
Vegetable oils contain trace metals. Contamination with heavy metals can occur from the soil, transportation, the process of vegetables, and the packaging of oils. Even cavitation techniques effect heavy metal concentration in oils.
Minimize heavy metal exposure
Although it’s not possible to eliminate heavy metals from your diet completely, you can limit exposure by:
Following a healthy and balanced diet
To minimize heavy metal exposure from a specific food, eating a healthy and balanced diet consisting of various foods is recommended. As the FDA states, the presence of detectable levels of heavy metals in certain foods does not necessarily mean you should avoid them.
Even nutritious foods can contain contaminants because water, farming, and agroindustrialization cause contamination with heavy metals, so it's impossible to make heavy metal exposure zero. On the other hand, good nutrition has been advised to keep the body healthy and to protect against damage caused by contaminants.
Testing your well water
Water happens to be the main source of heavy metal exposure. Testing for heavy metals, such as arsenic, lead, mercury, and radium, is recommended if you use well water.
Using cooking techniques advised to minimize heavy metals
You can minimize some heavy metal content through proper cooking techniques. For example, you can reduce rice's arsenic content by 40–60% by cooking it in excess water. Use 6–10 units of water for 1 unit of rice and drain the excess water after the rice is cooked.
In conclusion, it's not possible to avoid heavy metal exposure altogether. Regulations and laws are ruled to limit heavy metals in foods and water. It's best to follow a healthy and balanced diet containing various food groups to support your health and minimize heavy metal exposure from a specific food.
Heavy metals are naturally found in water, soil, the atmosphere, and the environment.
Exposure to heavy metals can cause acute and long-term health problems. Tolerable intake levels are set by authority health organizations, and heavy metals in foods are regulated by law to protect public health.
It's impossible to completely eliminate heavy metals from the food chain. Therefore, actions toward minimizing heavy metal exposure are the number one priority to prevent health hazards.
- Centers for Disease Control and Prevention. Arsenic.
- The Food and Drug Administration. What You Can Do to Limit Exposure to Arsenic.
- Centers for Disease Control and Prevention. Lead in Foods, Cosmetics, and Medicines.
- Centers for Disease Control and Prevention. Mercury.
- Centers for Disease Control and Prevention. Cadmium.
- National Library of Medicine. Nickel Toxicology.
- National Cancer Institute. Nickel Compounds.
- European Food Safety Authority (EFSA). Fish: scenarios indicate benefits versus risks.
- The Food and Drug Administration. Advice about Eating Fish.
- The Food and Drug Administration. Cadmium in Food and Foodwares.
- The Food and Drug Administration. FDA Issues Final Guidance to Industry on Action Level for Inorganic Arsenic in Apple Juice.
- The Food and Drug Administration. Arsenic in Rice and Rice Products Risk Assessment Report.
- World Health Organization. CADMIUM, Evaluations of the Joint FAO/WHO Expert Committee on Food Additives (JECFA).
- Science of The Total Environment. A comprehensive image of environmental toxic heavy metals in red meat: A global systematic review and meta-analysis and risk assessment study.
- Environmental Monitoring and Assessment. Concentrations of toxic heavy metals and trace elements in raw milk of Simmental and Holstein-Friesian cows from organic farm.
- Biological Trace Element Research. Concentration of Potentially Toxic Elements in Vegetable Oils and Health Risk Assessment: a Systematic Review and Meta-analysis.
- Food and Drug Administration. Lead in Food and Foodwares.
- Centers for Disease Control and Prevention. Drinking Water FAQS.
- Foods. Heavy Metals in Foods and Beverages: Global Situation, Health Risks and Reduction Methods.