Heavy Metals: The Toxins Hiding Out in Your Kitchen

Heavy Metals: You may remember being introduced to heavy metals in your high school chemistry class, but may not be aware of the role they play in your health.  Heavy metals are just as they sound – naturally occurring elements that are at least five times denser than water[1]. While heavy metals are found naturally in our environment, and some are even necessary for health (such as zinc and iron), humanmade contamination of heavy metals poses a threat to human health.

Low-level, constant accumulation of heavy metals in our normal daily habits can lead to significant disruptions in our health.

Some of the most common heavy metals studied in relation to human health are arsenic, cadmium, lead, mercury, and thallium.

• Lead is found naturally in small amounts in the earth, but most of our exposure comes from human activities[2]. Lead is used for a wide variety of items, including pigments in some paints, car batteries, and weights. Lead is toxic to anyone in certain amounts, but unborn babies and children under three are most at risk for lead poisoning.
• Arsenic also occurs naturally in the earth, but dangerous levels of exposure again stems from human activities. When arsenic combines with other elements to create inorganic compounds[3], it can be used for manufacturing glass, forming pesticides, pressure-treating wood, and more. Arsenic can dissolve in water and end up in the soil, and eventually food.
• Like the other heavy metals, cadmium occurs naturally in soil and rocks but is also used for the processing of items such as batteries and plastics. Our exposure to cadmium is through the air when plants, animals, and humans inhale or eat contaminated food or water[4].
• Mercury is a heavy metal that can be in liquid or solid form. When mercury enters the water, it is taken up by aqueous plants and, as a result, the animals that eat them, including larger fish. This is especially concerning as the concentration of mercury increases as larger fish eat it, making it more toxic[5].
• More toxic than the other heavy metals, thallium can be transferred from water to soil and into food crops and drinking water[6]. Thallium comes from water treatment plants or in certain fertilizers where plants take up thallium from the ground. Humans are then exposed by eating food grownin the soil[7].

How are humans exposed to heavy metals?

As mentioned above, much of our exposure to heavy metals come from contaminated food and water, but personal care products, including cosmetics and nutritional supplements, can also be a source of exposure.

Plants can absorb the heavy metals from the soil and water, but products can also be exposed during manufacturing processes. While there are naturally occurring heavy metals in the ground, most of the additional exposure comes from farming or manufacturing contamination, such as pesticide use, mining, or pollution. And certain plants and crops will absorb more of the heavy metals than others.

Heavy metals can accumulate in the soil outside of farming areas as well. Lead, for example, is found in soil contaminated with runoff from streets or remnants of lead-based paint and pipes.

In recent years there have been multiple independent studies and reports examining sources of heavy metals in food and other products.

Several examples of exposure include:]

• Rice: In 2012, Consumer Reports analyzed more than 200 samples of rice products and found measurable levels of arsenic in nearly every sample. While no official federal limit exists, the study found that certain rice samples had almost one and a half times the arsenic allowed in safe drinking water.
• Fish: Unfortunately, our oceans are contaminated with mercury, and levels continue to rise.  Larger fish can accumulate mercury by eating smaller fish. Regularly eating sushi made with larger fish like sea bass, tuna, and swordfish can even cause mercury poisoning.
• Baby food and fruit juice: Consumer reports examined 50 samplesof popular baby food, organic and conventional, to test for heavy metals including cadmium, inorganic arsenic, and lead[8]. All products had detectable levels of at least one of the metals, and two-third had levels that were reported as “worrisome.” Fifteen had levels the report stated would cause “potential health risks” for children eating only one serving a day. The Environmental Defense Fund also examined baby food and juice and found lead in nearly all the samples[9].
• Supplements and protein powder: An independent study examining popular protein powdersfound detectable levels of lead and cadmium in at least 70% of the samples[10]. Plant-based powders scored the highest in heavy metal content. Another study that examined prenatal supplements found arsenic, lead, and thallium in many of the samples[11].
• Cocoa: Another independent test conducted by Consumer Labs examined cocoa powderand found excessive amounts of cadmium in the majority of the samples, with three to five times more than the amount allowed by the World Health Organization[12].
• Cosmetics and personal care items: Heavy metals are also commonly found in cosmetics, and daily use directly onto the skin of many of these products is a health concern. Lead, mercury, cadmium, and arsenic have all been found in cosmetics, especially in colored items such as lipsticks[13].

Heavy metals and human health

The effects on human health can be both acute and longer-term. Acute toxicity can cause organ damage and even death. But lower-level chronic exposure can be equally as damaging with long term implications including cardiovascular disease, cancer, reproductive disorders, and neurological conditions.

Lead exposure can affect nearly every part of the body, especially the central nervous system[14]. Excessively high levels can cause brain and kidney problems. Children are especially vulnerable to the central nervous system effects with exposure causing significant cognitive development issues. Heavy metal exposure at a young age can reduce IQ, lead to ADHD or other behavior issues.

Heavy metals may also disrupt the body’s natural immune system both by decreasing the response to vaccines, as well as increasing risks of disease and antibiotic resistance[15].

Certain heavy metals can make bacteria more aggressive and resistant to antibiotics after exposure to metals such as lead[16].

Arsenic and mercury have been linked to increased risk of respiratory infections and other immune system interferences in children and adults[17]. Mercury may also worsen the autoimmune condition[18].

Exposure to lead in utero has also been shown to cause changes in the immune system and immune signaling molecules[19]. Alterations in the immune system can increase the risk of cancer and other diseases later in life.

Additionally, the risk from these heavy metals can grow over time as they can remain in the body, increasing the risk of certain cancers, reproductive problems, chronic disease, and cognitive impairment. Low levels of lead from food may also contribute to cardiovascular disease mortality[20].

How can you limit exposure to heavy metals?

Regulation of metals is overseen by the FDA and EPA, depending on the source. In the US the FDA recently formed the toxic elements working group to address the growing concern of heavy metal contamination in products[21]. But even according to the working group, this work may not be enough. Measuring overall exposure due to the dose-response of eating many foods with small amounts of heavy metals make the task more difficult.

The state of California has the strictest testing and labeling policy for heavy metals in consumer goods.  Proposition 65 was approved by California voters in 1986 as an answer to growing concern about toxic chemicals in household items and food[22]. With the passing of Proposition 65, California has to publish an annually updated list of chemicals known to cause cancer, birth defects, or reproductive harm. Companies also have to inform consumers if a product they purchase has a chemical from the list, or if it’s in a building, work, or living environment. Proposition 65 also protects California drinking water as businesses can’t release chemicals into drinking water. Cadmium, lead, mercury, and lead are just a few examples of the many toxins included on the Proposition 65 list.

Otherwise, many consumers are unaware of the potential for exposure to heavy metals in foods and personal care products. Consumer Reports states that nearly 50% of parents incorrectly assumed that children’s food is better regulated for safety than other foods[23].

While supplements are technically under the FDA, they are not regularly tested. Supplement companies may also opt for a third-party verification of purity called USP (US Pharmacopeia) to ensure there are no contaminants in the product.  NSF International is a similar label reserved for dietary supplements to test for toxicology and contaminants[24]. Supplements that have these verifications are likely a safer choice.

The Takeaway:

More oversight is needed to establish safe and acceptable levels of these heavy metals in our foods and products. While the FDA has initiated newer proposed guidelines, there is still much to be done. Consumers should not have to worry about contaminants in our food that are causing significant health concerns.

In the meantime, try to limit your intake of processed foods or any ingredients known to be high in heavy metals. Looking for cleaner beauty options and nutritional supplements is also essential to help keep you and your family safe from heavy metal exposure.

References:

[1] Tchounwou, Paul B, Clement G Yedjou, Anita K Patlolla, and Dwayne J Sutton. “Heavy Metals Toxicity and the Environment.” EXS 101 (2012): 133–64. https://doi.org/10.1007/978-3-7643-8340-4_6.

[2] CDC. “Glossary of Metals,” June 13, 2019. https://www.cdc.gov/nceh/clusters/pubs.htm.  PDF file.

[3] IBID

[4] IBID

[5] IBID

[6] Peter, A. L. John, and T. Viraraghavan. “Thallium: A Review of Public Health and Environmental Concerns.” Environment International 31, no. 4 (May 2005): 493–501. https://doi.org/10.1016/j.envint.2004.09.003.

[7] Karbowska, Bozena. “Presence of Thallium in the Environment: Sources of Contaminations, Distribution and Monitoring Methods.” Environmental Monitoring and Assessment 188, no. 11 (2016). https://doi.org/10.1007/s10661-016-5647-y.

[8] Reports, Consumer. “How Much Arsenic Is in Your Rice?” Consumer Reports. Accessed May 5, 2020. https://www.consumerreports.org/cro/magazine/2015/01/how-much-arsenic-is-in-your-rice/.

[9] Environmental Defense Fund. “EDF Report Finds Lead in 1 in 5 Baby Food Samples.” Accessed May 5, 2020. https://www.edf.org/media/edf-report-finds-lead-1-5-baby-food-samples.

[10] “Health & Fitness – Clean Label Project.” Accessed May 5, 2020. https://cleanlabelproject.org/health-fitness/.

[11] Schwalfenberg, Gerry, Ilia Rodushkin, and Stephen J. Genuis. “Heavy Metal Contamination of Prenatal Vitamins.” Toxicology Reports 5 (March 6, 2018): 390–95. https://doi.org/10.1016/j.toxrep.2018.02.015.

[12] ConsumerLab.com. “ConsumerLab.Com Finds Popular Cocoa Powders Contaminated.” Accessed May 5, 2020. /news/more%5Fpopular%5Fcocoa%5Fpowders%5Fcontaminated/08-05-2014/.

[13] S, Borowska, and Brzóska Mm. “Metals in Cosmetics: Implications for Human Health.” Journal of applied toxicology : JAT. J Appl Toxicol, June 2015. https://doi.org/10.1002/jat.3129.

[14] “Long-Lasting Effects of Childhood Lead Poisoning – Consumer Reports.” Accessed May 5, 2020. https://www.consumerreports.org/children-s-health/protect-kids-long-lasting-effects-childhood-lead-poisoning/.

[15] “Linking Pollution and Infectious Disease.” Accessed May 5, 2020. https://cen.acs.org/environment/persistent-pollutants/Linking-pollution-infectious-disease/97/i11.

[16] “Arsenic Exposure and Prevalence of the Varicella Zoster Virus in the United States: NHANES (2003–2004 and 2009–2010) | Environmental Health Perspectives | Vol. 123, No. 6.” Accessed May 5, 2020. https://ehp.niehs.nih.gov/doi/10.1289/ehp.1408731.

[17] Farzan, Shohreh F., Zhigang Li, Susan A. Korrick, Donna Spiegelman, Richard Enelow, Kari Nadeau, Emily Baker, and Margaret R. Karagas. “Infant Infections and Respiratory Symptoms in Relation to in Utero Arsenic Exposure in a U.S. Cohort.” Environmental Health Perspectives 124, no. 6 (2016): 840–47. https://doi.org/10.1289/ehp.1409282.

[18] “Low-Dose Inorganic Mercury Increases Severity and Frequency of Chronic Coxsackievirus-Induced Autoimmune Myocarditis in Mice | Toxicological Sciences | Oxford Academic.” Accessed May 5, 2020. https://academic.oup.com/toxsci/article/125/1/134/1668193.

[19] Winans, Bethany, Michael C. Humble, and B. Paige Lawrence. “Environmental Toxicants and the Developing Immune System: A Missing Link in the Global Battle against Infectious Disease?” Reproductive Toxicology (Elmsford, N.Y.) 31, no. 3 (April 2011): 327–36. https://doi.org/10.1016/j.reprotox.2010.09.004.

[20] “Low-Level Lead Exposure and Mortality in US Adults: A Population-Based Cohort Study – The Lancet Public Health.” Accessed May 5, 2020. https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30025-2/fulltext.

[21] Nutrition, Center for Food Safety and Applied. “What FDA Is Doing to Protect Consumers from Toxic Metals in Foods.” FDA, April 22, 2020. https://www.fda.gov/food/conversations-experts-food-topics/what-fda-doing-protect-consumers-toxic-metals-foods.

[22] jnelson. “Proposition 65 in Plain Language.” Text. OEHHA, January 22, 2016. https://oehha.ca.gov/proposition-65/general-info/proposition-65-plain-language.

[23] “Heavy Metals in Baby Food: What You Need to Know – Consumer Reports.” Accessed May 5, 2020. https://www.consumerreports.org/food-safety/heavy-metals-in-baby-food/.

[24] “Supplement and Vitamin Certification – NSF International.” Accessed May 5, 2020. https://www.nsf.org/consumer-resources/health-beauty/supplements-vitamins/supplement-vitamin-certification.