by Dr. John Neustadt

It’s a clear, crisp morning and you’re out early for your morning jog. You work up a good sweat, heart thudding, legs pumping, and when your run is finished, you shower and sit out back with a cup of morning coffee with almond milk. The birds are singing, the sky is bright blue, and you’re ready to get to work. Maybe you’re a little more fatigued than you’d like, and maybe your joints are a bit achy, but the last thing you are thinking about is heavy metal toxicity. 

Toxic metals, sometimes called heavy metals, include mercury, arsenic, lead, cadmium, and other metals that are naturally occurring in the earth’s crust. They’ve been used by humans for thousands of years and are the oldest toxins known. 

Toxic metals are everywhere, but they’re invisible. They’re carried on the wind and the jetstream, in the water and soil and in our foods. Two studies evaluating herbal dietary supplements from Asia even discovered them in those products. Having studied toxic metals and their health impact and having seen first-hand their devastating impact on my patients, I insist that all NBI dietary supplement raw materials and finished products are tested for toxic metals. I take my own products I create, and I wouldn’t want me, you or anyone else to be ingesting dangerous metals. 

Metal toxicity—especially from heavy metals like mercury, cadmium, arsenic and lead–affects all organ systems and can result in wide-ranging and nonspecific symptoms; however, the central nervous system (CNS) is especially susceptible to damage from metals. Metals are used in a wide range of industries and products: agriculture, medical applications, technology (our smartphones, smart tv’s and computers, for instance), our food and fish and dental fillings, our food and water. 

In food, metals can accumulate in plants and animals, which can end up in the food we eat. Fish are especially common sources of mercury contamination. Using your smartphone or watching your television won’t exposure you to metals; however, during their manufacturing or when they get recycled, metals can be released into the environment. If the metals get into the air we breathe, their small particulate size in the air is dangerous because it can penetrate the lungs and enter the bloodstream.

Metals with the highest degree of toxicity include arsenic, cadmium, lead, and mercury; they’re systemic toxins that in high enough amounts damage organs such as the kidney, blood and brain. When we’re exposed to these metals, they can increase our risk for heart disease, cognitive impairment, immune system problems, neurological issues and kidney damage. They can also contribute to cancer, according to the U.S. Environmental Protection Agency and the International Agency for Research on Cancer. 

Toxic Metals Exposure is Increasing

This article summarizes information on the most common toxic elements—mercury, lead, cadmium, and arsenic—with special emphasis on mercury. Metals harm us by forming free radicals, resulting in DNA damage, oxidized low-density lipoprotein (LDL) cholesterol (“bad” cholesterol), depletion of important antioxidants such as glutathione, and more. They cause direct and indirect damage to mitochondria, the energy producing parts of our cells.

In this day and age of rapidly advancing climate change, the level of toxins and metals we are exposed to has increased, particularly through wildfire smoke and flooding. Significant levels of toxic metals are released into the environment during wildfires—not only into the air, but into local waters at levels that can exceed that of typical wastewater. Metals such as mercury can travel for thousands of miles in the atmosphere before returning to earth in rainfall or as a dry gas.

That’s why it’s so important to understand the symptoms that might be associated with heavy metal exposure, and to consider testing your levels of heavy metals. It’s essential for clinicians to assess risk for acute and chronic toxic metals exposure, as this may help identify one significant underlying cause of chronic illness. If you’re concerned that what you’re experiencing might be caused by accumulation of toxic metals, I encourage you to speak to your healthcare provider about it. 

Here are just a few of the symptoms and conditions that can be linked to toxic metal poisoning:

Table 1: Symptoms of toxic metal poisoning

Mercury: Persistent, Prevalent and Toxic

Of all the toxic heavy metals, mercury (named for the planet) is one of the most prevalent and persistent problems. It’s been designated by the World Health Organization (WHO) as one of the ten most dangerous chemicals to public health. Although mercury was once believed to have medicinal qualities—and was, in fact, widely used in the United States and Europe, in particular to treat syphilis during the 15th-century European syphilis pandemic—all forms of mercury are toxic to humans. The central nervous system is particularly sensitive to damage by mercury-induced glutathione depletion.

It has been estimated that as much as 8000 metric tons (over 17 million pounds) of mercury are released into the atmosphere every year from burning coal and natural gas and refining petroleum products, cement production, and even creating consumer products.

Mercury is a well-established neurotoxin and a poison to the nervous system. Mercury can be found in amalgams, fish, water, air and vaccinations. Mercury is capable of inducing a wide range of physical symptoms, including alopecia (hair loss), autoimmune diseases, memory loss, decreased IQ, drowsiness, poor balance (ataxia), irritability, insomnia, tremors, forgetfulness, skin discoloration (melanosis, keratosis), excessive salivation, fatigue and more.    

Mercury works like a hidden human enemy in the body, damaging essential enzymes, proteins and fatty acids that keep cells functioning. It damages our very DNA. There is no known safe level of exposure to mercury.

Mercury from Dental Fillings

One common source of exposure to mercury is silver amalgam dental fillings. These contain approximately 50% elemental mercury, along with silver, copper and tin. Chewing food and gum, tooth brushing, and consuming hot beverages all release mercury vapor from the amalgams, which can then be absorbed. However, if your mercury amalgam filling is more than 20 years old, most likely it’s no longer releasing mercury. 

Mercury from Food

Another major source of mercury toxicity is fish consumption. The species of fish that have high levels of mercury are tuna, swordfish, shark, king mackerel, and tile fish. The US Environmental Protection Agency (EPA) published guidelines for fish consumption, and recommends women of child bearing age, pregnant women, nursing mothers, and children completely avoid eating these fish, while limiting to no more than 12 ounces weekly of fish that are lower in mercury (shrimp, canned light tuna, salmon, pollock, and catfish). 

When advisories about local fish stocks have not been issued, the EPA recommends women and children consume no more than 6 ounces per week of fish caught from local waters and consume no other fish that week. The contamination of fish with mercury is a major public health concern since many people worldwide rely on fish as their major protein source, and fish consumption has increased as more people learn of the health benefits of omega-3 series polyunsaturated fatty acids found in high amounts in fish. 

Lead: Low Levels Can Damage

Even though lead has been removed from paint, the metal persists in our water, in brass plumbing fixtures, soil, dust, and imported products. Lead can cause damage to the brain, kidneys, heart, bones, intestines, reproductive organs and the nervous system. Even at low levels, lead can cause irreversible damage and often without any obvious physical symptoms. Lead exposure can lead to chronic kidney disease, poor balance, learning disorders, hyperactivity, headache, convulsions, cardiovascular disease and more. It is well known that lead exposure in children has been repeatedly linked with irreversible behavioral problems and declines in IQ.

Lead inhibits the body’s ability to make hemoglobin, the oxygen carrying part of our blood. It interferes with the development of our own internal pain-reducing opiate system—called endorphins and enkephalins. It harms us by mimicking and competing with calcium and preventing calcium from entering cells. Lead is picked up by mitochondria and damages them. 

In 2016, Flint, Michigan suffered a catastrophic lead poisoning event. The city’s water supply was contaminated with lead, a problem that still persists years later. In 2019, the CDC reported that at least 4 million U.S. households still are exposed to high levels of lead and about half a million kids have tested positive for lead in their blood. 

Arsenic: In Your Water, Rice and Chicken

Arsenic contamination affects millions of people globally. Around 140 million people in over 50 countries are exposed to drinking water that is contaminated with arsenic. Food is also a significant source of arsenic exposure—in seafood, rice, mushrooms and poultry.

Arsenic toxicity affects the entire body. It’s a risk factor for cancer, numbness and tingling in the extremities (peripheral neuropathy), hearing loss, skin discoloration (melanosis, keratosis) and more. It causes mitochondrial dysfunction, lipid peroxidation (oxidation of fats), and cell death. It has been linked to cardiovascular disease, diabetes, problems with the central and peripheral nervous system and cancers of the kidney, skin, and bladder.

Cadmium: A Remarkably Long Half-Life

Cadmium is widespread in the environment—it can be found in nickel-cadmium batteries, as a pigment in paint, and is used in producing polyvinyl chloride plastic, in cigarette smoke and sewage sludge. Long-term exposure to cadmium through air, water, soil, and food leads to cancer and organ system toxicity such as skeletal, urinary, reproductive, cardiovascular, central and peripheral nervous, and respiratory systems. Cadmium binds to mitochondria and inhibits their function, leads to cellular and DNA damage, and depletes critical antioxidants such as reduced glutathione (GSH) and important antioxidant enzymes, such as catalase, manganese-superoxide dismutase, and copper/zinc-dismutase.

Metals in Supplements: An Overlooked Source

You do the hard work of eating healthy, exercising, and trying to lead a balanced life that nourishes both body and soul. You keep up with the latest studies on nutrition and dietary supplements, and make sure to include supplements that can keep your nutrient intake optimal, and ward off disease. And then you find out that dietary supplements can also expose you to metals, including arsenic and lead and mercury!

Multiple studies have detected toxic levels of metals in dietary supplements from Asia. You can protect yourself from potential metals exposure by verifying that the ingredients in the dietary supplement you want to purchase have been tested for purity. This may be listed on the label and manufacturers that test for contaminants should have certificates of analysis available to verify the purity of their products.

Given the increased use of dietary supplements and the fact that many integrative medicine physicians prescribe dietary supplements, special attention should be given to a series of recent studies showing contamination of dietary supplements with heavy metals, especially in products containing whole herbs used in Traditional Chinese Medicine (TCM) and Ayurvedic Medicine. Ayurvedic medicine is an ancient medical system from India. A systematic review of TCM products determined that poisoning with toxic metals was “reported with some regularity.” 

A survey of Ayurvedic dietary supplements produced in South Asia and sold in 20 stores in the Boston area in 2006 revealed that 20% of the dietary supplements (14 of 70 Ayurvedic supplements) contained heavy metals. Furthermore, a 2002 case report documented lead poisoning from Ayurvedic medicine in a 41-year old male. This man complained of malaise, weakness, abdominal pain, and weight loss. His blood lead level was high, and the lead caused anemia. 

Another case report from 2002 described arsenic toxicity in a 39 year old woman taking the dietary supplement Chitosan. This supplement is derived from chitin, which is found in shellfish. It’s used to help people lose weight by blocking the absorption and storage of fat. The woman reported to the Emergency Room complaining of fatigue, headache, and weakness for the past 6 months. She had been taking 6 capsules daily of the “fat blocker” pills for a year. Testing revealed severe arsenic poisoning and an analysis of the pills showed an arsenic concentration of 135.5 ng/g/capsule. Shellfish is a known reservoir of arsenic, and no other sources besides her dietary supplement could be identified.

What You Can Do About Toxic Metals

Since metal toxicity masquerades as other conditions, and since chronic exposure to metals, especially to mercury, is common, metal toxicity should be on people’s radar. If you take dietary supplements, make sure that the company that makes the products tests the raw materials and finished products for toxic metals, like NBI does. 

A series of simple questions can help discern someone’s risk. Combining these questions with knowledge of your symptoms can help you’re your healthcare provider determine if additional testing is warranted to rule out heavy-metal toxicity.

The good news is that metal toxicity can be addressed and mitigated. Sources of toxicity can be reduced by filtering your water and air. Chelating substances, such as cilantro, can bind to metals and help remove them from the body. Glutathione, our most potent endogenous antioxidant, is one of our most important defenses against heavy metals. Glutathione levels can be supported with building blocks such as taking N-acetyl-cysteine (NAC) or through direct supplementation with glutathione. Taking a whey protein powder can also increase glutathione. 

For mercury in particular, we can reduce exposure. Mercury amalgams should be avoided, and can be safely removed with a knowledgeable, biologic dentist. Smaller fish such as sardines and herring have far less mercury than larger fish such as tuna. Selenium supplementation to support adequate selenium levels may be protective, since mercury can displace selenium. 

Additionally, since a major route of excretion of toxins and metals is in bile, bitter herbs that stimulate bile flow may be helpful. These include herbs such as artichoke (Cynara scolymus) leaf, dandelion (Taraxacum officinale) root, and burdock (Arctium lappa) root. A high-fiber diet and colon hydrotherapy, may also be helpful. During chelation, milk thistle (Silybum marianum) silymarin, one of our most potent liver-protective herbs, is also frequently recommended by integrative practitioners.

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