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Heavy Metal Toxic Exposure Can Severely Affect Brain Health

Oct 28th 2020 | By Susan Luck, RN, BS, MA, HN-BC, CCN, HWNC-BC

anatomical human brain, mesh vector, scientific article design and medical booklet

As American life expectancy continues to increase, the pressing concern has shifted from living longer to living healthier. However, try as we might, we cannot escape the many environmental chemical exposures we come into contact with daily.

Many of the diseases we have been taught to think of as part of “normal” aging may, in fact, be manifestations of our body’s accumulation of heavy metals and other toxins.

Science based research along with innovative testing, can offer clues to many of the cognitive issues that we are seeing, across the life span.

The term heavy metal refers to any metallic chemical element that has a relatively high density (molecular weight) and is toxic or poisonous at low concentrations. Heavy metals are natural components of the Earth’s crust. They cannot be degraded or destroyed. These metals can enter our bodies via food, drinking water, and air. As trace elements, some heavy metals (e.g. copper, selenium, zinc) are essential to maintain crucial processes in our function and metabolism. However, at higher concentrations they can lead to toxicity.

Hope is Happening Booklet

Heavy metals include mercury (Hg), cadmium (Cd), arsenic (As), chromium (Cr), thallium (Tl), and lead (Pb). Heavy metals tend to bioaccumulate. This means that even small concentrations of the chemical in a person can have a deleterious impact over time. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted.

Studies show that heavy metals in the body may be implicated in everything fromAlzheimer’s and cognitive decline, behavioral problems, kidney dysfunction, Parkinson¹s, epilepsy, and cardiovascular disease. Exposures to heavy metals including mercury, lead, aluminum, and cadmium, have been found in the cord blood of babies whose mothers were smokers.

At Rezilir, testing for heavy metals and many other environmental toxins is part of our assessment along with genetic markers to understand one’s unique ability to detoxify and clear the body of these substances along with and to implement protocols to lessen one’s toxic burden.

Overview of Heavy Metals

heavy metal toxins


Lead exposure from the environment can occur through drinking water, food, air, soil, and from old paint dust and chips containing lead. Lead in paint was banned in 1978.

In 1986, lead piping was banned from use in new U.S. plumbing systems, but lead remains throughout much of the country’s drinking water infrastructure, which largely pre-dates the ban. Until 2014, plumbing fixtures with as much as 8% lead-by-weight could be legally labelled “lead free.”

The EPA estimates that 10 to 20 percent of human exposure to lead may come from lead in drinking water as demonstrated in water testing throughout the United States

Besides neurotoxic effects, lead can cause problems in the synthesis of hemoglobin, stress the kidneys, gastrointestinal tract, joints, reproductive system, and acute or chronic damage to the cardiovascular and nervous system. A 2018 study published in The Lancet Public Health suggests that of the 2.3 million deaths every year in the US, about 400,000 are attributable to lead exposure, of which 250,000 are from cardiovascular disease.

dr craig tanio of rezilir health in south florida

There is persuasive evidence that lead can have small, subtle, subclinical effects, particularly on neuropsychological developments in children. With the elimination of lead-based house paint, and the increased use of lead-free gasoline, lead poisoning is certainly less prevalent. However, low-level toxicity is still an issue.

The EPA warns that if lead is not detected early, children with high levels of lead in their bodies can suffer from damage to the brain and nervous system, behavior and learning problems (such as hyperactivity), slowed growth, headaches, and more. Adults can experience high blood pressure, muscle and joint pain, digestive problems, nerve disorders, and memory and concentration problems.

Lead is still used widely in the manufacturing, construction, and chemical industries. Coal burning power plants still spew lead into the atmosphere. The major industries where lead is still used includes: batteries, alloys, pigments and compounds, cable sheathing, and ammunition. Lead pipes used to supply water have largely been replaced but still exists in some places.

It is important to check your local municipal water supply and your home for old layers of lead paint in your interior and exterior walls.


It has been researched for decades that once aluminum enters the body, it bio accumulates in brain tissue and contributes to cognitive impairment and memory loss. Significant amounts of aluminum can be found in food emulsifiers, antiperspirant deodorants, hair sprays, baking powder, many types of toothpaste, in our drinking water, and in much of our cookware, exposing us to high amounts over the course of one’s lifetime.

There has been much speculation, therefore, that aluminum may be one of the prime factors contributing to the onset of Alzheimer’s disease.The connection between aluminum and Alzheimer’s disease became more evident, when in 1995, the Journal, Neurotoxicology(31 Dec 1994, 16(3):413-424), reported that the widespread use of aluminum salts to purify water could account for the large numbers of people suffering from Alzheimer’s.

Aspergilloma of the brain and close-up view of fungi

Recently, the final piece of the puzzle may have fallen into place: the connection between aluminum and fluoride. New research has revealed that fluoride in drinking water makes the aluminum that we ingest more bio-available. As was reported in Brain Research (Vol.7 84:98), the combination of aluminum and fluoride causes the same pathological changes in brain tissue found in Alzheimer’s patients.

Note:There is a significant difference between metallic aluminum and plant-derived aluminum, which is in the form of aluminum hydroxide. No studies have ever shown a connection between aluminum hydroxide and toxic levels of aluminum in the human body — which is a good thing, because there is a lot of it in our food supply.


Mercury is another heavy metal that has toxic effects and bioaccumulates. Mercury is naturally occurring and is found in soil, rocks, wood, and fuels like coal and oil. Simple soil erosion deposits mercury in rivers and lakes, but concentrations generally remain low, unless erosion reaches extraordinary levels.

Common exposures to Mecury include: eating fish or shellfish contaminated with methylmercury, breathing vapors in air from spills, incinerators and industries that burn mercury-containing fuels, release of mercury from dental work and medical treatments, breathing contaminated workplace air or skin contact during use in the workplace (dental, health services, chemical, and other industries that use mercury).

Human-generated sources such as coal plants emit approximately half of atmospheric mercury, with natural sources such as volcanoes responsible for the remainder. An estimated two-thirds of human-generated mercury comes from stationary combustion, mostly of coal.

lead poison

Other important sources include gold production, non-ferrous metal production, cement production, waste disposal, crematoria, caustic soda production, pig iron and steel production, mercury production (mostly for batteries), and biomass burning. Mercury and its compounds are commonly used in chemical laboratories, hospitals, dental clinics, and facilities involved in the production of items such as fluorescent light bulbs, batteries, and explosives.

But the major source of mercury is found in our food chain and is responsible for about 1/3 of the levels found in our bodies. Mercury that naturally occurs in coal production is released during burning and enters the air; it is then precipitated into the oceans, lakes, and rivers by rain.

According to the EPA, coal-fired power plants in the United States emit about 48 tons of mercury into the air every year — and more than half of this mercury falls within 5 miles of the plant itself. When it reaches the water, microorganisms consume it and convert it into a substance called methyl mercury. Methylmercury works its way up the food chain, reaching high concentrations among populations of some species.

Larger species of fish, such as tuna or swordfish, are usually of greater concern than smaller species. The U.S. Food and Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA) advise women of child-bearing age, nursing mothers, and young children to completely avoid swordfish, shark, king mackerel and tilefish (golden bass), to limit consumption of albacore (“white”) tuna to no more than 6 oz (170 g) per week, and of all other fish and shellfish to no more than 12 oz (340 g) per week.

A 2006 review of the risks and benefits of fish consumption found that for adults the benefits of one to two servings of fish per week outweigh the risks, even (except for a few fish species) for women of childbearing age, and that avoidance of fish consumption could result in significant excess coronary heart disease deaths and suboptimal neural development in children.

The consumption of fish is by far the most significant source of ingestion-related mercury exposure in humans, although plants and livestock also contain mercury due to bioaccumulation of mercury from soil, water and atmosphere.

The nervous system is very sensitive to all forms of mercury. Methyl mercury and metallic mercury vapors are more harmful than other forms, because more mercury in these forms reaches the brain. Exposure to high levels of metallic, inorganic, or organic mercury can damage the brain, kidneys, and developing fetus.

Effects on brain functioning may result in irritability, tremors, changes in vision or hearing, and memory problems. The term, “Mad Hatter,” refers to 19th Century workers who used mercury to make hats and went bald and suffered from severe muscular tremors, dementia, and fits of wild, uncontrollable laughter.

Short-term exposure to high levels of metallic mercury vapors may cause health problems including lung damage, nausea, vomiting, diarrhea, increases in blood pressure or heart rate, skin rashes, and eye irritation. Mercury toxicity has been associated with hypertension, decline in cognitive function and Alzheimer¹s Disease, coronary heart disease, heart attack, stroke, generalized atherosclerosis, and kidney disease.

Young children are more sensitive to mercury than adults. Mercury in the mother’s body passes to the fetus and may accumulate there. It can pass to a nursing infant through breast milk. Women are advised to avoid dental work prior to and during pregnancy and breast feeding.

Mercury’s harmful effects that may be passed from the mother to the fetus include brain damage, mental retardation, lack of coordination, blindness, seizures, and inability to speak. Children poisoned by mercury may develop problems of their nervous and digestive systems, and kidney damage. Mercury has an affinity for fetal tissue and accounts for it’s implication in birth defects. In 2002, the National Academy of Sciences found strong evidence for the toxicity of methyl mercury to children’s developing brains, even at low levels of exposure.

A recent study from the Centers for Disease Control found that as many as 637,233 American children are born each year with mercury levels of more than 5.8 micrograms per liter, the level associated with brain damage and loss of IQ


Cadmium derives its toxic effects from its chemical similarity to zinc, an essential micronutrient for plants, animals, and humans. Cadmium has become a more prevalent cause for concern in recent years.

Like lead, it is an underground mineral that did not enter our air, food, and water in significant amounts until it was mined as part of zinc deposits. Now there is widespread environmental contamination with cadmium. Cadmium may actually displace zinc in some of its important enzymatic and organ functions and can interfere with these functions.

The zinc-cadmium ratio is very important, as cadmium toxicity and storage are greatly increased with zinc deficiency, and good levels of zinc protect against tissue damage by cadmium. The refinement of grains reduces the zinc-cadmium ratio, so zinc deficiency and cadmium toxicity are more likely when the diet is high in refined grains and flours.

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Cadmium is bio-persistent. Once it is absorbed, it stays in the body for years (even decades), although it is eventually excreted. We get most of our exposure from our food via the soil it¹s grown in. Luckily, cadmium is not well absorbed by digestion.

Cigarette smoke plus industrial burning of metals puts some cadmium into the air. Cadmium levels in the atmosphere are much higher in industrial cities and it is more harmful when inhaled. Soil levels of cadmium are increased by cadmium in water, by sewage contamination, by cadmium in the air, and by high-phosphate fertilizers.

Coffee and tea may contain significant cadmium levels. Root vegetables such as potatoes may pick up more cadmium in the soil, and grains can concentrate cadmium. Seafood, particularly crustaceans, including crab and lobster, and mollusks, such as clams and oysters, have higher cadmium levels, although many are also higher in zinc, balancing the cadmium.

During the growth of grains such as wheat and rice, cadmium (from the soil) is concentrated in the core of the kernel, while zinc is found mostly in the germ and bran coverings. With refinement, zinc is lost, increasing the cadmium ratio. Refined flours, rice, and sugar all have relatively higher ratios of cadmium to zinc than do the whole foods.

One pack of cigarettes contains about 20 mcg. of cadmium, or about 1 mcg. per cigarette. About 30 percent of that goes into the lungs and is absorbed, and the remaining 70 percent goes into the atmosphere to be inhaled by others or to contaminate the environment. With long-term smoking, the risk of cadmium toxicity is increased. Though most of it is eliminated, a little bit is stored every day.

Marijuana may also concentrate cadmium, so regular smoking of cannabis may also be a risk factor for toxicity from this metal.

Metal workers, zinc miners, and anyone who works with zinc galvanization may accumulate more cadmium. Those who drink soft water; those who smoke or inhale second hand smoke, coffee and tea drinkers, and those who eat refined flours, sugars, and white rice are also likely to receive greater exposure to cadmium. Occupational exposure to cadmium has been implicated in a significant increase of lung and prostate cancer.

Cadmium toxicity has been implicated in generating prostate enlargement, possibly by interfering with zinc. Cadmium may also produce bone defects (osteomalacia, osteoporosis) in humans and animals. In addition, the metal can be linked to increased blood pressure and effects the myocardium in animals. Cadmium may also cause anemia, yellow teeth discoloration and loss of smell (anosmia).


heavy metal testing

At Rezilir, we work with specialty Labs to test for heavy metals as part of our comprehensive assessment, followed by an individualized treatment protocol.


Avoid exposures in the workplace, home, food chain

  • Say no to new amalgam fillings and, if possible, have a dentist who understands the process to replace your existing mercury fillings.
  • Avoid aluminum cookware and aluminum-based deodorants.
  • Limit eating high-mercury fish including swordfish, shark, orange roughy, and albacore tuna.
  • Test your water at its source entering your home for all heavy metals.
    Filter fluoride and lead out of your drinking water and avoid in toothpaste.
  • Evaluate products around the home for toxic metals (e.g., fertilizers, fungicides, insect or rodent poisons, lead-based paint, refinishing chemicals, household cleaning agents, hobby supplies, photographic chemicals, batteries, etc.) Keep these products in their original containers.
  • Read labels every time you buy a product and choose safer products when at all possible.
  • Keep all potentially toxic products well away from children.
  • Dispose of light bulbs, batteries, and other items safely.
  • Calculate your mercury intake here:

Schedule an Environmental Education and Coaching session with our Environmental Expert


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