Heavy metal contamination of foods has become an ever-increasing concern to environmental and health authorities for the past few decades.
It is clear that heavy metals can be toxic to living organisms beyond repair and that our environment is riddled with them. Many people look for the right way to detox heavy metals and avoid heavy metal poisoning. However, defining the fine line between safe and toxic has proven to be somewhat of an on-going challenge. The outcome depends largely on the dose, form and overall elimination ability of the organism.
When taking heavy metal regulation112 into your own hands, you may find our heavy metals calculator helpful in gaining insight as to how much heavy metals you truly consume on a daily basis.
If you know the average concentration in ppm of a heavy metal in a certain food, simply type it in below alongside the amount of the food you consume daily to keep track of your exposure.
What most people perceive to be a 'heavy metal' rather refers to a toxin; or more accurately, the point at which and the form in which any metal exceeds natural environmental levels or is presented in a toxic form and becomes damaging to a living organism. According to science, this view of heavy metals is not entirely accurate.
The truth is that the term 'heavy metal' has a unique meaning depending on who you're asking and in what context. A metal-worker may categorize a heavy metal according to weight, a physicist due to atomic number and a chemist due to the chemical behavior.
Scientifically, a heavy metal is defined by the following characteristics:
The periodic table of elements is generally divided up into heavy metals, light metals, metalloids and nonmetals, all of which display unique properties like the ones listed above.
The definition of 'heavy metals' often also encompasses heavy metalloids, which have a combination of both metal and nonmetal properties; further twisting the true meaning of the term.
While there is evidence that quite a few ancient civilizations knew about the potential dangers of arsenic, mercury and lead, the first scientific investigations regarding heavy metal toxicity only truly appeared in modern literature in the early 1800s. The Industrial Revolution had sparked an urgent need for research into metal toxicity, as people who lived or worked near factories were suddenly coming down with mysterious symptoms that often resulted in premature death if left untreated.
Unsplash / American Public Power Association
The term 'heavy metal' began to be popularized from this time as it was assumed that these elements are more toxic due to their heavier weight, larger particle size and tendency to accumulate in the tissues of living organisms.
Isorepublic / Konstantin Kolosov
However, heavy metals are not the only metals that are known to bioaccumulate or cause serious damage in the wrong form and concentration. Pretty soon the term was loosely applied by the general public to include any other deleterious metal toxins, like aluminum (a light metal) or arsenic (a heavy metalloid).
It took scientists roughly about a century to collect data on heavy metals and work out the forms, concentrations and conditions in which they are truly toxic. Safety regulations regarding metals began to appear from the 1950s onward, yet only really took off as being commonplace worldwide with the creation of the EPA in the 70s. Furthermore, global scientific understanding of heavy metal toxicity and safety is incomplete, with more research refining the regulations every few years.
In spite of all the hype, one cannot ignore that heavy metal contamination is not just a product of mankind.
Life on Earth has evolved to use metals in all chemical reactions – to a chemist, these reactions are what life boils down to being.
Metals are used in up to 50% of all the proteins our cells produce and 100% of all chemical reactions that take place in the body. Since heavy metals are a native to all life on Earth, living organisms developed systems in order to cope with exposure to elements that disagreed with their unique biochemistry.85
Learn how to help your body detox heavy metals.
The following information is by no means a substitute for professional heavy metal chelation therapy. Heavy metal detoxification may yield severe consequences if undertaken in the absence of a skilled professional who understands all parts of the elimination process and the complex chemistry of metals.
Unsplash / ThisisEngineering RAEng
In humans, all four of the sulfhydryl-reactive (-SH) metals: lead, arsenic, mercury, and cadmium, are metabolized in the liver where they are bound to sulfur-containing amino acids.86
Pixabay / LillyCantabile
Upon uptake into a cell, heavy metals are processed for elimination in several ways:
After being sufficiently processed in the liver, the –SH metals are generally moved back into the digestive tract via bile to be excreted later on (with the exception of arsenic which is only excreted via urine). Some portions make it into blood circulation and are excreted via urine and sweat.
In the liver, digestive tract and the entire alimentary canal, the microbes of our microbiome work tirelessly to convert inorganic heavy metals into organic forms so that they may be eliminated efficiently.88
The result leaves the gut vulnerable to a wide array of toxins including heavy metals, opportunistic pathogens and bacterial by-products, with an impeded ability to auto-regenerate.
Pixabay / mcmurryjulie
The average gut repairs itself within 3-5 days92, but only if fed a steady supply of nutrients that only a robust microbiome can deliver. Butyrate93,94 is a prime example and produced by both lactobacillus and Bifidobacterium strains.
Heavy metals that make it to the systemic blood supply are prone to bioaccumulating in tissues. Whether they get that far depends on the dose, form and state of the microbiome.
Unsplash / Robina Weermeijer
Heavy metals can enter blood circulation via:
Once in circulation, they can deposit in every organ and tissue, but tend to adopt a preference for fat molecules. The nervous system is largely composed of fatty tissue and is therefore a prime site of deposition for all four –SH metals.
When elimination gets kick-started, these metals are forced back into circulation from out of the tissues in which they were accumulating.
This allows for either complete clearance or redistribution into other tissues. The outcome depends on whether the body has enough resources to stabilize the metal – if not, the body dumps it in a new tissue for later processing.
Each of the metals has a unique profile in this regard. For example, arsenic elimination demands continuous transition of arsenic between a highly toxic (trivalent) form and relatively non-toxic (hexavalent) form until it exits the body.95 Other metals are metabolized into organic forms before being reduced into stable inorganic forms.96,97,98
It’s virtually impossible to pinpoint exactly where the body is during the constant process of heavy metal elimination. However, one can support it’s clearance mechanisms in their entirety through leading a healthy lifestyle and keeping the body well-nourished.
When the metal elimination systems of the body have been overburdened for an extended period of time, it can give rise to subclinical nutritional deficiencies and an increased rate of bio-accumulation of such metals.
For –SH metal elimination to function optimally, the body needs to have an adequate supply of sulfur containing compounds, particularly the amino acids methionine and cysteine. This ensures that these metals are bound, but the elimination of them depends further on the state of the kidneys and digestive tract.
Pexels / Anna Shvets
Other nutrients often lacking, yet vital for efficient heavy metal metabolism include:
Exercise is vital to jump start metal metabolism and just about every other kind of metabolism at the cellular level in the body. “Move it or lose it” is the common axiom prescribed in this context and it is 100% truthful for many areas of our health.
Breaking a sweat is required for heavy metal detox from the body and when one does so, blood moves better around the body, more energy is generated through cellular respiration, clutter is pushed out of cells and room is made for more elimination to be achieved. A sauna may aid in this regard, but the result is minimal and takes a lot longer to achieve.
Pexels / Samuel Silitonga
Heavy metal pollution has been consistently occurring on the planet for millions of years. It’s unavoidable given that all elements are found naturally in the Earth's crust, with a tendency to redistribute around the planet's ecosystem through the course of time.
Natural events (that have shaped Earth's ecosystems since life began) have been contaminating the environment with heavy metal pollution for much longer than humans have been on the planet. Examples of these natural events include:
Unsplash / USGS
There are records that suggest that volcanic activity on the planet is older than 2700 million years (as with the Blake River Megacaldera Complex in Canada1) and the oldest wildfire is believed to have begun approximately 420 million years ago. This makes our ±5-8million year evolution seem like a dismal speck of dust by comparison!
Life on Earth was derived from and made to tolerate the above described forms of metal contamination; or we would not be here today.
Just like inside the body of all living organisms, the trillions of microbes in the environment work hard to ameliorate the effects of the naturally occurring heavy metal toxicity that arises through all of the above events.
Organic substances produced by these bacteria, such as humic and fulvic acids, are capable of:
Furthermore, every time pollution is released into the environment, it either encounters or contains black carbon and other molecules that are known to bind to heavy metals and other pollutants.2
Seeing as life on Earth has evolved to handle natural forms of heavy metal pollution, it begs the question: has heavy metal pollution ever truly been a problem?
While humanity has made a significant contribution to metal pollution on the planet, it is debatable whether it could serve to topple the natural order of things when placed in a broader context. There is plenty of evidence to suggest that we have been adding to the natural heavy metal pollution on the planet for thousands of years without fault.
High levels of copper, zinc, mercury, lead and cadmium are often released into the environment as a result of smelting metal ores.3 Heavy metal pollution in quantities far exceeding modern safety limits has been documented from ancient caves that once served as smelting sites.4
Clemens Schmillen / Wikimedia Commons
Evidence of such heavy metal pollution dates as far back as 8000 BC5; however, it is still being debated when humans first truly discovered fire - the original source of manmade pollution. The oldest remnants of humans burning fuel stems back to about 1.5 million years ago6, suggesting that it's very likely that we have been living with our own heavy metal pollution for more than a millennium.
However, when studying human bones from different historical periods, scientists have noticed a clear trend for rising heavy metal contamination between the Neolithic era (±12000-4500 BC) and the Bronze, Roman and Byzantine periods (3000 BC - 1453 AD).7
In light of this, at what point should heavy metal pollution be considered a menace to human health?
According to the current evidence, humanity has been living with high levels of heavy metal pollution for a long time with little to suggest that it has been blatantly harmful to civilizations of the past.
A few interesting modern studies were published with respect to heavy metal levels detected in the fossilized bones of both fish and seals from the Stone Age (dated between 6300 BC and 3800 BC).
Unsplash / Clint Bustrillos
The scientists reported that the level of mercury found in the fish bones was 20 times greater than the maximum amount considered safe by the European Food Safety Authorities. The seal bones contained amounts up to 15 times greater! Both the fish and seal samples also contained at least 4 times as much cadmium than what is considered the safety limit by modern standards.8
Considering that these ancient remains were evidently butchered in large numbers and found upon historical refuse sites near village ruins; it brings a new depth to the common understanding of heavy metal pollution and the original Paleo Diet.
In today's world, the pollution is notably higher from decades of industrialization and yet just one look at the common trends between Blue Zones9 (where people commonly live to being over 100) will prove that the traditional diets and lifestyles our ancestors followed still promotes longevity and well-being, even under the current conditions we live in.
While this seems paradoxical, there are a few plausible explanations as to why this is the case.
Some researchers say that the large amounts of dietary antioxidants and nutrients that our ancestors consumed (such as trace minerals and essential vitamins), helped to maintain a good tolerance toward heavy metal toxicity. The common dietary trends of today are lacking in several essential nutrients that are vital for heavy metal elimination, which is why many people have turned to using trace mineral supplements, like Shilajit.
Technically, the safety of any metal depends entirely on situational factors which can potentiate or lessen the danger. The form the metal is in, the concentration, whether it can be utilized for biological processes, how it is ingested, the size of the particles, etc11 are all factors that would affect ultimately just how dangerous any given heavy metal is for the body.
To simplify matters, it may be easiest to think of heavy metals and their safety in terms of two main categories:
While all metals are technically inorganic, a distinction has been made in chemistry between organic and inorganic metals as a way to refer to whether they are bound to an organic substrate or not.
In nature, the majority of elements are only found in a bound form.
Organic metals are generally the by-product of bacterial processing, bound to carbon substrates that tend to make them less reactive and less toxic. Free metals tend to be highly reactive, with loose electrons on their surface that are known to damage other particles in the quest to complete the metal’s outer atomic shell.
Unsplash / USGS
The pitfall of organo-metals is that they can be more easily absorbed by cells with a higher bioavailability, which may produce a quicker reaction when initially exposed. Through the elimination process, organic metals can be changed into a variety of forms that may produce symptoms of toxicity before being stabilized and removed.
In spite of that, organic metals are quicker to pass out the system and usually easier for living organisms to tolerate with minimal damage.
Once again, this depends on the dose and the tolerance of the organism. A person’s tolerance to heavy metals is a reflection of their ability to metabolize and eliminate the toxin, which is linked with multiple factors such as overall toxin exposure, nutritional status, and age.
While heavy metals can be equally toxic in either form, life on Earth appears better equipped to tolerate metals in an organic form.
Some inorganic heavy metals are found in a neutral bound form in nature and are ingested by us every time we inhale dust particles in the air. These tend to pass through our systems unnoticed, as most particles are too large to be broken down efficiently and absorbed before being excreted.
Organic metals and inorganic metal salts from nature are present in a specific 3D orientation (chirality), whereas most synthetically produced metal salts are not. It is theorized that the natural chirality of organic molecules helped to shape the receptors on the surface of living cells to facilitate absorption. In this way, synthetic versions are simply not the right shape to fit the biochemical lock at the cellular level.
Unsplash / Kunj Parekh
Inorganic metals are typically metals that have been freed from their bonds through a chemical reaction.
The term can also apply to synthetically-produced metal salts and non-organically bound metals in nature.
Generally speaking, inorganic metals are far more toxic to organic life until they are bound safely and their charge is neutralized.
When consumed by an organism, inorganic and organic versions of the same metal are usually metabolized in almost the same way. Inorganic metals tend to undergo additional steps in order to be eliminated and are more likely to cause extra harm in the process.
Did You Know: Chemistry is a Journey Toward Stability
Any metal element that is not bound is ultimately unstable and capable of causing harm in any living system until stability has been achieved. The usual trend is for particles in nature to reach a balance and achieve stable neutrality, which generally requires for them to be bound in one form or another.
Heavy metals get released from their chemical bonds due to combustion or any other similar chemical reaction. Thus, industrial pollution, volcanic eruptions and raging wildfires are all sources of inorganic metal pollution that burden the environment.
Unsplash / Tobias Seidl
However, pollution in any form is nothing new to the trillions of microbes that inhabit the Earth’s surface. Thanks to their persistent survival efforts, the habitat is hospitable for all other organic life on the planet.
When combustion occurs, a variety of both inorganic and organic metal species are generated. The chemical instability creates much ionic turbulence, rapidly shifting the distribution of elements. Many of the organic species, while bound, are just as unstable as the inorganic varieties and are referred to as ‘Volatile Organic Compounds.’ These compounds tend to stabilize shortly after being exposed to air.
Both organic and inorganic metals can bio-accumulate in the tissues of plants, microbes and animals. Whether bioaccumulation occurs or not depends on the form and how well the elimination systems of the organism perform.
All metals are found in trace amounts in and on the Earth’s crust with varying degrees of rarity. Many heavy metals form an essential part of the food chain and are required for important biological reactions inside plant and animal cells alike.
Isorepublic / NordWood Themes
It is also observed that trace amounts of many non-essential heavy metals are found ubiquitously throughout living tissues. Several of them are capable of participating in chemical reactions by trading with similarly charged essential elements (such as rubidium and cesium).12
In some instances, a minor replacement of ions can prove beneficial for the organism. Yet if the host were to become overwhelmed with the non-essential metal, it may cause deprivation of the essential metal and that would lead to multiple health concerns.
Industrial operations increase pollution and concentrate heavy metals in the environment surrounding them. Many industries attempt to reduce their pollution output through profiteering from the process, selling back the metal portions for use in other industrial purposes and products.
Prime examples of where some of our collective heavy metal pollution goes include:
In the sense of heavy metal pollution, modern farming practices trade sustainability for maximum yields and product homogeneity. So it is hard to say what foods exactly are high in heavy metals.
Unsplash / Ibadah Mimpi
It’s not to say that there aren’t safety regulations that limit heavy metals in agricultural products that most farmers use. However, the metals are known to bio-accumulate in soil, water and living tissues, causing a shift in soil bacteria and fertility status. Farmers try to employ cost-effective strategies like crop rotation to help the soil recover. As a result, the food crops they grow tend to have accumulations of these metals in various quantities.
As you can imagine, this makes the pollution in fresh produce difficult to both assess and regulate. Most crops are not screened for the full spectrum of contaminants they may harbor.
Pexels / Magda Ehlers
This applies not only to food crops, but to other crops as well, such as cotton, which happens to be sprayed with one of the few approved commercial applications of mercury (as a fungicide).
Did You Know: Some Heavy Metals Are Actually Important for Health
It may surprise some people to know that many essential trace minerals are in fact heavy metals and can be toxic in large doses or if taken in the wrong form. This should come to no surprise as all elements form the basis of which life is built.
The list of metals essential to our health includes:
We would like to say that the best quality Shilajit is preserved at high altitudes on the slopes of isolated, wild mountain ranges and therefore is free from all pollution in its natural state. However, even samples collected from some of the most remote ecosystems in the world are now starting to show records of having trace amounts of pollution in them (such as seen in Antartica).13
We are not saying that all Shilajit is unpolluted however, merely that in its natural state at high altitudes it contains safe levels of heavy metals; many of which are in forms, concentrations and ratios that are either benign or fantastic for the health of living organisms.
Pollution appears to be unavoidable given the current practices of modern civilization.
In light of the fact that...
...we believe Shilajit is one of the best natural food supplements you can possibly find on the planet for dealing with pollution.
Pexels / eberhard grossgasteiger
Toxic heavy metal contamination in Shilajit is far more likely to be a side effect of low quality processing. When Shilajit is collected, it contains natural impurities (stones, lichen, etc) and therefore it is important to purify it.
Producers of a low quality product are prone to:
It's this deadly combination that makes low quality Shilajit potentially hazardous.
In the case of good quality Shilajit, there are little to no heavy metals found to enter the purification process and the active ingredients are fully preserved, making it highly beneficial for all living organisms. Freeze drying and other methods are available that do not raise the temperature of the Shilajit above 102°F (39°C), serving as a part of the golden standard for Shilajit processing to those in the know.
For more information on Shilajit purity, take a look at our guide on how to go about identifying good quality Shilajit.
There is no single golden standard that has been approved globally for safe levels of heavy metals and other pollutants found in food, supplements, other supplies or the environment.
Every country maintains its own set of safety standards that are generally founded on relevant bodies of scientific work that have been building over the last century.
In the United States, heavy metal safety is controlled and enforced by the FDA when it relates to a food or dietary supplement, like Shilajit. Other federal agencies that play a role in heavy metal safety regulation include the EPA (where environmental pollution is concerned) and the USDA (for animal products).
Additionally, state and local laws may enforce their own safety regulations, which impact businesses operating at a national or global level, such as is the case with California Proposition 65.
The Food and Drug Administration (FDA) forms a branch of the federal Department of Health and Human Services. It is responsible for instituting safety regulations pertaining to heavy metals and other contaminants found in foods, drugs, cosmetics and medical devices.14
Working together with the USDA and EPA, the FDA has created heavy metal safety standards that conform with national data.
Every year, multiple branches of each agency tests hundreds of products, environmental samples and average blood levels of pollutants across the population to keep track of heavy metal pollution throughout the US.
This data is then used to detect hazards and devise strategies to minimize pollution in the supply chain - where possible. Often exposures to heavy metals and pollutants are multifactorial with an overlap between the environment and food production.
A classic example would be the advances in culling lead pollution in the US.
Pexels / Polina Tankilevitch
Lead is well known for inducing neurotoxic and carcinogenic effects, being of particular concern to growing children, developing fetuses and pregnant women. Exposure has mostly crept in through the use of leaded fuel, which is absorbed by plants, consumed by livestock and concentrated in cities and abundant in industrial operations.
As soon as it was understood that blood levels of lead were causing toxic effects in the 60’s, permissible lead levels in fuel were set to lower every decade15 until eventually being “phased out” in 1996.
Currently, the permissible level is 0.05gram per gallon in unleaded fuels and 2grams in leaded aircraft fuels. This helped to lower lead levels in products across the spectrum, yet it is still permissible as a fuel additive in fuel for farming equipment, marine engines and racecars.16
In spite of major efforts to eradicate pollution, the reality is that until highly advanced sustainable technology is developed to facilitate pollution-free manufacturing, it will be impossible to eradicate man-made heavy metal pollution without moving away from industrialization entirely.
The FDA continues to survey lead levels in products, calculating whether the lead detected would be harmful if ingested.
According to their guidelines, the minimum blood level of lead that would cause harm to children is 3mcg/dL and 12.5mcg/dL in adults. These figures are intentionally set to be nearly 10 times lower than the actual levels required by the CDC’s safety standards. Referred to as Interim Reference Levels, they are updated to reflect current data when pertinent.18
In addition to the standards set by the FDA, the state of California has issued its own heavy metal safety regulation. While officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, it is generally known as California Proposition 65.
California Prop 65 demands that businesses inform citizens of California of any contaminants in their products that may cause cancer, birth defects or reproductive harm. This is typically achieved through a warning label on the product and is only a requirement in the state of California.19
Chemicals regulated by California Prop 65 can be viewed here .
California adopts much stricter heavy metal safety standards than the FDA. In many instances these standards are nearly impossible to attain given the environmental history and distribution of certain pollutants.
Originally this initiative was set in place to serve Californians and protect against groundwater contamination. Sadly the regulation’s expansion to other commodities has also served as a legal trap for small businesses who cannot afford the resulting legal fines.
Lead is a prime example, with the Californian standard being set at 0.5mcg, in spite of its high prevalence in the environment due to past fuel contamination. In this respect, even ordinary vegetables are likely to miss the mark
Pexels / Magda Ehlers
There are still large gaps in our collective understanding of heavy metal toxicity today and therefore the standards that govern heavy metal safety are also in their infancy.
What is deemed as safe or toxic is a reflection of the scientific understanding of heavy metal toxicity at the time that a consensus was reached in the form of a safety standard.
The science to back up the majority of safety standards that have been proposed for any potentially hazardous substances were extrapolated from the following:
Even though many are dying to know what is truly safe, it is far too unethical to get a direct answer by conducting toxicology trials on humans. Intelligent guesses on the actual safe levels were concluded from these types of trials and from that, a basic frame of reference for heavy metal safety was built.
It can be expected for safety regulations to change as we learn more about the complex interactions between heavy metals, living organisms and the environment.
Pexels / Andrea Piacquadio
Lead, mercury, arsenic and cadmium are deemed some of the worst pollutants worldwide and are under close surveillance in the US by the FDA and related bodies of authority.
The list of metals has a reputation for consistently heavy metal poisoning humankind throughout history. In spite of much investigation, scientists are still trying to pinpoint the exact forms and concentrations of each that gives rise to toxicity, potential benefit or a neutral effect.
With this in mind, let us consolidate the facts and take a look at what is known thus far about these 4 infamous heavy metals.
It’s not random that these four metals are often singled out in the quest to minimize global pollution.
Unsplash / Arthur Lambillotte
Lead, mercury, arsenic and cadmium all have an affinity for sulfur-containing molecules (such as amino acids and crucial DNA signaling molecules) and tend to disrupt hundreds of cellular processes as a result.20
In their respective toxic forms and concentrations, these four metals are known to be carcinogenic and neurotoxic. As all of them have the tendency to bioaccumulate in all other tissues, symptoms of toxicity can be generalized and non-specific for each type. However, each metal does seem to preferentially adopt differing deposition sites in the body (aside from the nerves), giving rise to a subset of unique symptoms for each that have characterized their individual toxicology profiles for centuries.
While they have minor differences in their modes of toxicity, the way the body metabolizes and eliminates these four metals is more or less the same. The profile of each metal is discussed in detail below.
Lead is a dull grey-colored metal that has had a long-standing relationship with humanity. Since the dawn of alchemy, lead has been associated with Saturn, the Father of Time.
The malleability of the metal, the way it could be manipulated to create pigments (namely white, red and blue), its corrosion-resistant properties and later on, its chemical prowess as a fuel additive all contributed to its early attractiveness as an industrial material.
Modern uses of lead still extend to:
Lead can still be found in fuel at low levels as well as in old pipes, pottery and paint.21
According to the WHO and many other credible organizations, there “is no safe level of lead exposure”.
That is to say, no safe level that has currently been found in the scientific literature to date. Lead appears to be toxic at all levels tested and in most forms, with primarily the in-organic forms being worse for us than their organic counterparts.
Toxic in-organic lead species can be generated via combustion, mining operations and other industrial activities.
It is interesting to note that organic lead has a far higher bioavailability than inorganic lead, which would increase its inherent toxicity. However, lead is typically ingested in an in-organic form before being converted to multiple toxic organic forms in the gut – the prime mechanism for how it becomes toxic in the first place. This is also a description of the beginning steps our body takes naturally to eliminate such toxins, allowing for them to be taken up, broken down and neutralized for smooth excretion. If the elimination systems of the body are not functioning properly, the toxicity of the compound is orders of magnitude worse.
In spite of the ban on leaded fuels, fuel combustion is still the leading form of lead exposure for most individuals today.
Pexels / Polina Tankilevitch
The majority of lead that deposits in the body rests in the bones, while small fractions reside in the blood, digestive organs, lungs, kidneys, heart and other soft tissues.24 In children, lead primarily acts as a neurotoxin.
An average individual stores approximately 120mg of lead in their bones. Lead stores are also known to mobilize out of the bone alongside calcium stores, which allows for it to re-enter circulation and re-distribute to other body compartments.
Carbon, silicon and germanium all fall into the same elemental group as lead and therefore lead toxicity may cause the stores of these elements to be displaced.
Lead poisoning can cause anemia, iron loss, impaired nutrient uptake, gut inflammation, DNA damage and may promote tumor growth.25 Further symptoms or conditions caused as a result of lead toxicity include:
It is interesting to note that lead toxicity appears to make people aggressive and hyperactive through the way it interacts with the hippocampus in the brain.26
Lead has been extensively studied in baby foods as children are deemed the most vulnerable to lead poisoning. The following types of baby foods contained high levels of lead on average27:
Lead is also found to contaminate all industrial plastic products alongside cadmium. PVC and other heavy duty plastics are likely to contain lead28, which extends to the majority of packaging for appliances and home goods such as stoves, fridges and mattresses.
Children are at risk of lead poisoning and SIDS (sudden infant death syndrome) from such products. As lead and cadmium have been detected in plastic soft toys, it is advisable to limit exposure of such toys to very young children.
In nature, it is more common to find lead in neutral Pb-Pb complexes or locked inside mineral ores than it is to find it organically bound to carbon or any other element. Lead can be found naturally in the Earth’s crust at 11 ppm.
Unsplash / Elena Mozhvilo
Lead bound in complexes is relatively non-absorbable and thus less toxic. Organic lead has a higher bioavailability, making it potentially more toxic initially, however it tends to have a faster clearance rate than inorganic lead. Inorganic lead is converted to organic lead compounds by the gut microbiome to facilitate swift removal or is taken up by cells and reduced into less toxic forms; adding to the length and severity of symptoms depending on the form and concentration.
Lead has no known internal benefits but has been used externally for approx. 2000 years in early medicine, especially in Roman practices. It has a poor absorption through skin and can be used in trace amounts to disinfect wounds and treat ulcers. Throughout the 1800s and even up until the 1950s in some countries, plasters prepared with a lead paste (diachylon plasters) were commonplace in homes for cuts, sores and ulcers.29
Lead has a higher abundance in the Earth’s crust than the other top heavy metals, sitting at 15 ppm.30
According to the WHO, there is no safe level of lead exposure. It is estimated that the daily intake of lead on average per person is about 0.1mg.
What foods are high in this heavy metal? Lead appears to have an affinity for accumulating in roots and root vegetables, such as sweet potatoes; however it can be found ubiquitously in very low amounts in all fruits and vegetables.
In spite of its toxic reputation, mankind seems to have been fascinated with mercury for thousands of years. Cinnabar, the natural mineral version of mercury, has been used as a red pigment by early humans since Paleolithic times (more than 30 000 years ago) to paint caves.35
Mercury was revered by alchemists as it was the only substance in which gold could dissolve and is still largely used in the extraction of gold ores today.
Tumblr / newlifeplease
Mercury is most toxic in its organic forms, with methylmercury in fish being of particular concern.
When inorganic mercury is released into the environment, aquatic microbes convert it into organic methylmercury. Thereafter it continues to accumulate in the marine food chain, with the largest deposits found in predatory and long-lived fish.
Elemental mercury is about 50 times less toxic, however is still known to induce the severe symptoms of mercury poisoning as it is bio-transformed into organic species the moment it enters the gut microbiome.
Research has shown that the methylmercury levels found in predatory fish rivals that of the organic mercury compounds that constantly form in the gut of those who have mercury-based dental fillings. Dental amalgams pose the additional problem of releasing mercury vapor into the mouth of the patient for swift uptake by the lungs and brain, making them potentially twice as problematic.
Dental amalgams, fish, industrial pollution, cotton clothing and female sanitary products are the main routes of exposure for the majority of people. Elemental mercury vaporizes at most room temperatures, contributing to atmospheric pollution when industrial waste is mismanaged.
Great efforts are being made to phase out many of the above applications of Mercury in the near future.
Mercury is perhaps the most well-known neuro-toxin, famous for inducing madness in those unfortunate enough to suffer an acute overdose, get the heavy metal poisoning, or long-term chronic exposure (the origin for the expression “mad as a hatter”). This is reflected in the way mercury primarily accumulates in the brain and nervous system, more so than any of the other three metals discussed.
The liver is another vulnerable site for mercury deposition and damage. In the case of ingesting less absorbable forms of mercury (such as salts), the kidneys and gut lining are the main sites of toxicity.
Mercury, like cadmium, falls into the same elemental grouping as zinc and is known to deplete zinc and selenium stores in the body.
Mercury poisoning is primarily contained to affecting the brain and central nervous system, but will also negatively impact the gut and kidneys. Generalized symptoms can include:
In those exposed to large doses, mercury may induce shyness, delirium, hallucinations and suicidal ideation.37 Impaired speech, vision, hearing and other vital functions may also occur in severe cases.38
Unsplash / Vino Li
Seafood is the main source of mercury contamination in our diet, with mass-produced cotton textiles and laundry detergents being common secondary exposure sources.39
Predatory fish at the top of the food chain tend to have larger stores of organic mercury in their tissues. Here is a list of fish and other seafood that contains the highest levels of mercury:
While not often thought of as the worst of the mercurial marine offenders, shrimp, prawns and other bottom-feeders are susceptible to harboring toxic amounts of elemental mercury. This is due to the way the heaviest particles of mercury tend to fall to the bottom of any water body in which they are suspended.
Mercury is found in trace amounts throughout the environment suspended in bodies of water, in the water vapor molecules of clouds and in certain rock minerals and salts.
As a miniscule part of the water cycle of the planet40, trace amounts of mercury are inherent in every cloud, rain drop and body of water. Science is still exploring how it’s possible that atmospheric mercury maintains its stability41, but it is suspected that the mercury ions are held tightly in place by bands of hydrogen and halogen ions (e.g. chlorine).42
Similarly, rock minerals and salts keep metallic mercury bound in an inert non-toxic form, provided they are not ingested in large quantities.43
Unfortunately, any free forms of mercury are outright toxic, including the organic forms and therefore the safest forms of mercury are those that were left as they were originally found in nature. Mercury has a high affinity for carbon (or you could say carbon has a high mercury sequestering ability) and is easily adsorbed in soils where it remains contained and neutralized after a short time.
The safest organic form of mercury would be ethylmercury, which is known to pass through our systems with a minimal transient toxic effect44 (depending on dosage) and no bioaccumulation, according to the WHO.45
Elemental mercury has been used internally as a diuretic and externally as an antiseptic and disinfecting agent in trace doses. Applied externally, elemental mercury does not easily penetrate into skin unless wounded.46
Nowadays mercury is not used in treatment of infections or during surgery but is still available in some over the counter antiseptics like mercurochrome.
Ironically, this madness-inducing metal was used successfully to fight fire with fire during a Medieval European outbreak of Syphilis (a madness-inducing disease).47
Mercury is present at approximately 0.5 ppm in the Earth’s crust.48 It is estimated that our daily intake of mercury is less than 0.01mg and that it is present in everything we consume in miniscule amounts.
Seafood and rice (especially farmed in Asia)51 are natural sources of mercury, as are any water heavy crops, as mercury forms a core part of the planet's water cycle.
While all fish contains mercury, it’s important to consume fish as part of an overall healthy diet. Many nutrients in fish help to facilitate mercury metabolism such as selenium and omega-3 fats. The FDA has some good guidelines as to what fish are safe to eat and how often.
Arsenic has always been known for being toxic to the height of fatality, having a long-standing history as a royal tool for assassination. In spite of its dark history, arsenic has also been used through time in medical and industrial applications. However its use in this regard has dropped dramatically since the mid 1900’s.
The word arsenic is thought to derive from the Persian word zarnikh, which later evolved to take a position in ancient Greek as arsenikon, meaning ‘potent’ or ‘masculine.’ 52
The most toxic forms of arsenic tend to be in-organic, yet as seen with the other metals, certain organic derivatives of inorganic arsenic can be equally toxic.
Trivalent methylated arsenic species are examples of hazardous organic arsenic compounds and are also a by-product of its stabilization by microbes53 - both in the environment and the gut of living organisms. Ultimately microbes and cells work to chemically reduce this form of arsenic to a non-toxic form that facilitates safe elimination, through reduction reactions involving the amino acid methionine.54
Arsenic is efficiently absorbed with 80-90% of ingested inorganic arsenic being taken up systemically via the gut. The dose and degree to which the body’s metal metabolism pathways are functioning will determine how safe or toxic arsenic is ultimately.
Unsplash / mrjn Photography
Water is the main route of dietary arsenic exposure, either directly through the drinking water supply (more common in developing countries) or through crops irrigated with contaminated ground water.
According to some sources, arsenic is the twelfth most abundant element in the human body.57
The bodily distribution of arsenic depends on the type, concentration and phase of elimination, as it has a tricky propensity to keep redistributing to different bodily tissues during the elimination process.
As a result, Arsenic distribution is widespread with a tendency to accumulate in the following tissues:
Like lead, arsenic can interfere with bone mineral status, potentially replacing phosphorus and promoting the release of calcium (and any accumulated lead) from bone tissue.
Elemental Distribution of Arsenic in the Periodic Table
Arsenic falls into the same elemental grouping as nitrogen and phosphorus on the periodic table and thus may interfere with the status and distribution of these elements in the body as well.
Unsplash / Nhia Moua
Arsenic toxicity inhibits more than 200 cellular enzymes and causes widespread damage in the body. It negatively affects the heart, kidneys, liver, pancreas, nervous system and skin. Not surprisingly, in-organic arsenic is a known carcinogen.58
Like the other metals, symptoms of overall arsenic poisoning may include:
Exposure to toxic organic forms of arsenic can contribute towards worsening cardiovascular diseases such as atherosclerosis, as well as cancers and skin problems.
Systemic arsenic could tamper with the DNA’s ability to regulate protein transcription. This may contribute to an increased susceptibility to viral infections that use the host’s DNA to replicate.
Arsenic is known to heavily contaminate most rice products, including rice milk, infant formula containing rice and rice cereals.59 Up to 90% of the arsenic discovered in polluted rice samples was found to be inorganic and therefore toxic the moment it makes contact with the gut microbiome.
Other water-heavy grains like wheat and corn typically accumulate inorganic arsenic as well, if grown in chemically contaminated media.
Rice is more As-resilient than other grains and tends to be the crop of choice for agricultural land that was subject to arsenic-laden pesticides before their use was banned.
Pexels / Pixabay
Arsenic is the twentieth most abundant element in the Earth’s crust and rests at number fourteen in the ocean.
Many forms of arsenic exist (organic forms and inert salts) that are non-toxic unless ingested in large amounts. We come into contact with these forms of arsenic all the time, in the dust we breathe and the food we eat.
The organic form of arsenic that is commonly achieved through bacterial biotransformation is the pentavalent state known as dimethylarsinic acid (DMA). Ingested DMA, while still known to be toxic, passes through our systems with relatively more ease than other forms of arsenic.
Like mercury and many other toxic heavy metals, arsenic has some potential as an antiseptic and has been used in times past to treat infectious diseases, tumors and ulcers.
Trace amounts of arsenic, as present in our environment, may enhance the resilience of the gut microbiome by promoting antibiotic resistant gene expression in our friendly gut bugs and upping the production of beneficial nutrients (as seen in mice studies).60
Safer forms of arsenic are being investigated currently by the FDA in order to treat a unique form of leukemia (Acute Promyelocytic Leukemia) as well as some types of tumors.61 Arsenic trioxide has already been approved for clinical use in treating APL.62
Arsenic can be found in the Earth’s crust at between 1.5 and 2 ppm.63 According to a survey, average daily arsenic intake across 19 European countries was between 0.13 and 0.56 mcg per kg body weight per person.64
Many marine organisms contain organic arsenic species in them that are virtually harmless to us when ingested.67 As these compounds mimic Trimethylamine N-Oxide (also found in abundance in all animal products), they should be consumed in moderation to avoid upsetting the gut micro-environment.68
Broiler chickens need arsenic as part of their diet69 and are thus a natural source of arsenic in the diets of those who consume chicken or eggs.
Unlike the other metals, cadmium maintains humble origins in our history as zinc’s sidekick since its discovery in 1817.70
Cd element has been used in minimal applications by man and was initially just an air-polluting by-product of zinc and lead smelting, coal combustion and welding. Modern uses for cadmium include metal plating and galvanizing, pigments, batteries, plastic stabilization and as a nuclear particle absorbent in nuclear power plants.
Generally speaking, all forms of cadmium are toxic. The only non-toxic forms are those that are neatly tucked away in the Earth’s crust, bound and stabilized by elemental zinc.
We absorb 10-50% of all the cadmium we ingest, with smokers being exposed to much higher levels of cadmium on average.71
We are mainly exposed to cd element through fresh produce, combustion, smoking of cigarettes and industrial operations (like coal power stations).
Pexels / Pixabay
Cadmium is used to stabilize industrial plastics73 such as PVC and impart color in some cases.74 As plastics are widespread throughout society, we are exposed to cadmium compounds all the time through making use of such products (e.g. packaging, vinyl, piping). Kids are particularly at risk.
Cadmium is well known for accumulating in the kidneys and causing kidney damage in children.75 The liver is another prime site for deposition of the element, with other soft tissues and the nervous system containing lower amounts.
The body tends to battle to eliminate cadmium once it has been stored, most likely due to the way it targets two main elimination organs.
Cadmium is found one below zinc in the same elemental group on the periodic table and has been seen to act in a similar fashion on an ionic level. As a result, cadmium poisoning has the potential to knock vital stores of zinc and interfere with a wide range of zinc-dependent chemical reactions inside a living cell. The same has been observed with regard to cadmium and magnesium stores in the body.76
Cadmium, like the other heavy metals, tends to cause acute neurological toxicity when exposure concentrations reach toxic levels or it has been allowed to accumulate in the body over a long time. Kidney, heart and gut damage are also common.
Other symptoms include:
Cadmium is also a known carcinogen and has been implicated in provoking lung, pancreatic, breast and prostate cancers.
Unsplash / Deryn Macey
More than 70% of our cadmium intake comes from plant-based sources. All vegetables are known to accumulate cadmium in high quantities due to its high bioavailability to plants and low adsorption in the soil. Cereals, pulses and legumes tend to have the highest concentrations.78
Clams, oysters, mussels and other edible mollusks tend to have high concentrations of cadmium in them, as do benthic fish, organ meats and in mushrooms (grown in contaminated media).
Potatoes and tobacco appear to have higher levels than other foods, suggesting that cadmium may have a preference for members of the “deadly” nightshade family.
Other research suggests that cadmium has a higher affinity for accumulating in acid-loving plants such as potatoes and tobacco, being less bioavailable in soils with a higher alkaline pH.79 The majority of plants like to grow in a mildly acidic medium.
Inorganic cadmium is relatively stable and is not yet known to undergo biotransformation into organic versions of the element. Instead cadmium has the tendency to bio-accumulate in bacteria that are resistant to its toxicity80 or it precipitates back into rock mineral lattices.
We ingest cadmium all the time when we breathe as it tends to be present in most dust samples. The safest forms of cadmium are those we cannot absorb properly, which tends to be the larger particles that we inhale. 10-50% of the cadmium we breathe in gets absorbed, depending on the particle size.
According to an entry in the British Pharmaceutical Codex dated back to 190781, cadmium iodide was used to treat “enlarged joints, scrofulous glands and chilblains”. However, there is no evidence to date to prove that it would be effective in this capacity.
Certain pathogens are sensitive to cadmium, such as the bacteria responsible for causing botulism in food. Thus the presence of cadmium may help minimize the risk of infectious food poisoning.
Cadmium exists in the Earth’s crust at roughly 0.1 ppm. It is estimated to be consumed on average at amounts of between 10 and 35 mcg per day, with smokers ingesting considerably higher amounts.82
Cadmium is found all over the Earth’s crust and due to its high uptake by plants, cadmium is found in all food in trace amounts.
Many of our customers are concerned that consuming shilajit on a frequent basis may be problematic in terms of heavy metal accumulation and toxicity in the body.
As it happens, the nutritional components of the substance itself are geared toward enhancing cellular metabolism and elimination – provided it is good quality.
Our shilajit is top quality with regard to heavy metal safety standards - but you needn’t take our word for it!
Check out our Certificate of Analysis .
To address some public confusion on the matter of heavy metal pollution, we have attempted to put together a fuller picture of this widespread global phenomenon in order to offer a realistic perspective. The history, distribution, toxicity, safety and natural elimination of the top four toxic heavy metals are discussed.
It’s exactly this wide variety, however, that makes quality shilajit safe!
Good quality shilajit (collected from pristine mountains at high altitudes) boasts an abundance of essential trace minerals and other nutrients that the body requires on a daily basis to function optimally. The wide variety of metals present in shilajit and their ratios make them ideal for supporting cellular health. This is due to how the metal receptors in our cells are selectively flooded with metals that have the highest affinity – these tend to be the ones our cells need in order to function, like zinc and magnesium.
When heavy metals flood the food supply chain at the crop soil level, plants battle to get in all the nutrients they need and therefore become nutritionally depleted106, no longer offering us a wide selection of minerals which would have kept the elemental ratio in order.
Shilajit, with its carbon-rich composition, chemically binds pollutants and keeps them contained within its organic structure (including all four of the above metals).107,108,109,110,111 Furthermore, shilajit contains a wealth of amino acids, including cysteine and methionine.
Imagine Doing a Selective Search for all the Heavy Metals in Your Food…
Firstly, this is a rather impossible task as most companies do not run selective heavy metal testing on their products and most individuals cannot afford to privately test their food. Even if one managed to get everything they ate tested by multiple laboratories and the concentrations of these contaminants confirmed, the end result of such a task would likely shock most people. The reality is that heavy metals are an intimate part of our lives and present in every breath we take, whether we know it or not.
Nevertheless, it is important to minimize the toxins we are exposed to on a daily basis, but it is equally important to maximize our health in order to enjoy the benefits of industrial technology. Many supplements and foods, such as shilajit and fish, have potent health boosting properties that one would be missing out on if heavy metal exposure was the only consideration to be made.
While nearly everything about good quality shilajit spells elemental balance and improved well-being, it is not exempt from basic laws of nature. Therefore, just like anything in life, it can become problematic under the right circumstances.
Even though our shilajit falls well within heavy metal safety standards, you may still want to take the following precautions to be super safe:
For more information on how to take shilajit and shilajit dosage, check here.
Before you begin to panic about the heavy metal pollution you are exposed to, take a moment to remember that all metals can be potentially toxic at concentrations and in forms that disagree with the basic chemistry of our biology.
Safety standards are based on the science and epidemiological data that is currently known, making them a constant work in progress; the reality of which often lags behind the science.
Toxic metals are prevalent throughout the Earth’s crust and biosphere, with all life on the planet having developed cellular mechanisms to cope with natural exposure. Many of the nutrients found in shilajit are required for metal elimination and are known to be depleted in living organisms that have been overburdened with toxic heavy metals.
Pollution is heightened by the activities of man and is virtually unavoidable given modern circumstances. By being informed, minimizing environmental exposures and maximizing bodily well-being through enhanced nutrition and exercise, everyone can achieve their own biological balance with respect to modernized living.
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