What is heavy metal poisoning – why does it happen?

What are heavy metals and what is heavy metal poisoning? Toxic heavy metals such as arsenic, lead, cadmium and mercury can enter the environment – that is, in the air around us – and, as a result, our bodies. The good news is that if you know the sources of the pollutants posing the biggest threats to your health, you can reduce your personal exposure to them.

What holds the world together at its core? Heavy metals! The earth’s core of iron and nickel makes up a third of the mass of the entire earth and thus plays a major role in ensuring that gravity keeps us on the ground. Aluminium and iron are absorbed from the earth’s crust into the soils and plants, and our Stone Age ancestors already ingested them through their food. Not only that – volcanic eruptions have always ejected mercury and arsenic from the depths of the earth into the atmosphere.

In the last 150 years, however, industry, mining, power plants and road traffic have raised the emission of heavy metals to a whole new level. This is a problem. Because the toxic metals can accumulate in our bodies, trigger heavy metal poisoning and various diseases.

Find out about how heavy metals get into the environment and the human body, about heavy metal poisoning symptoms and causes and how you can treat heavy metal poising – for example, through chelation therapy. Moreover, moving forward, you read up on how to reduce your exposure to heavy metals in your everyday life.

What are heavy metals?

In chemistry, heavy metals are usually considered metals with a density of five grammes per cubic centimetre or more. By heavy metals, however, we almost always mean metals that can be toxic to us humans.

Heavy metals include aluminium, arsenic, lead, cadmium, chromium, cobalt, copper, nickel, mercury and zinc. Aluminium and arsenic are slight exceptions, in that aluminium is a light metal and arsenic is a semi-metal. However, both share many properties with heavy metals and can lead to poisoning in similar ways.

List of heavy metals^[1–6]

How have heavy metals emissions changed?

Fortunately, the first successful measures to counteract heavy metal emissions have already been taken. Lead-free petrol and lead-free water pipes, stricter waste disposal regulations – these and other measures have led to a significant overall reduction in heavy metal pollution.

Road traffic is primarily to blame for zinc, selenium and copper emissions in our atmosphere. Brakes and tyres lose small heavy metal particles through friction and release them into the environment. They are thus responsible for most of our exposure to copper, zinc and lead today.^[7]

The World Health Organization (WHO) warns that lead is always unhealthy, no matter how little of it we consume. Many health experts and environmentalists also warn that exposure to heavy metals is still far too high today.^[8–10]

How does heavy metal poisoning occur?

Both acute and chronic heavy metal poisoning are rare nowadays.The air we breathe today contains fewer heavy metals than it did 20 years ago. The limits set by our government for arsenic, lead, cadmium and nickel emissions have hardly been exceeded in the air we breathe since 2007. If heavy metal values in the emissions have been too high, these cases were mostly reported near industrial sites.^[11]

A more worrying way that heavy metals enter our body is through the food that we eat. Heavy metals rise into the atmosphere from the chimneys of power plants, factories and waste incineration plants – and from road traffic. They then transfer from precipitation and dust particles into the soil, where they accumulate and enter the groundwater.

From there, they are absorbed by vegetables and grains, for example. Lead and cadmium, among other metals, can then enter into the livers of cattle and pigs when they feed. Wild mushrooms absorb a lot of mercury and cadmium from the soil. Fish and seafood also absorb mercury from the environmental cycle.^[11]

Here are some further examples of how heavy metal poisoning can occur nowadays:^{[3, 22, 24, 30]}

• Heavy metal poisoning is mostly the result of industrial accidents in the metal industry and mining.
• If old mercury-containing thermometers break, the mercury can evaporate and get into the lungs.
• Occasionally, people get poisoned because they store food for a long time in ceramic dishes with a colourful lead-containing glaze – such ceramics are usually souvenirs from abroad.
• In rare cases, water pipes made of lead are still installed in old buildings, causing chronic contamination via the drinking water – this is particularly problematic when preparing baby food.
• Some traditional medicines, especially old home remedy ointments and Ayurvedic medicines and food supplements from Asia, can contain large amounts of lead and mercury.

Heavy metal poisoning: is soy high in nickel?

Can you get heavy metal poisoning from vaccines?

Some people are concerned about the fact that mercury and aluminium in vaccines are said to possibly cause neurological damage and cause autism. What is it about the metals in vaccines?

Aluminium salts are added to vaccines against tetanus, whooping cough and diphtheria, as well as some flu vaccines, to increase their effectiveness. The amounts of the heavy metal are small and insignificant compared with our everyday aluminium exposure from food, deodorants and other sources. Critics claim that aluminium causes muscle inflammation, chronic fatigue, neurological disorders and autism – but there is no evidence for this.^[13-15]

Most recently, a meta-analysis from the United States published in 2015, which took into account data from 1.3 million people, came to the conclusion that autism occurs just as frequently in unvaccinated children as in vaccinated children.^[13]

A similar discussion also took place regarding the mercury-containing preservative thiomersal used in vaccines. In this case also, studies could not establish a connection with cases of autism or other neurological damage. Nevertheless, thiomersal is almost no longer used in the United Kingdom – for precautionary reasons and to reduce environmental pollution with mercury.^[16]

On the other hand, your children are in danger when unvaccinated against certain diseases. Due to declining vaccination rates against measles, for example, there have been repeated measles outbreaks and even deaths in recent years. If too few children are vaccinated, this also endangers people who cannot be vaccinated for health reasons or for whom vaccines do not work.^{[17, 18]}

What are the long-term effects of heavy metal poisoning?

Our bodies needs particular metals to function – for example, iron, zinc, selenium and copper. But too high a dose of these essential trace elements can also pose a threat to your health.

Did you know that when you smoke cigarettes, you pave the way for cancer-causing heavy metals in your system. Cigarette smoke contains cadmium, lead and arsenic, among others.^[20] 

What diseases can heavy metals cause?

Researchers suspect that long-term exposure to arsenic, lead, cadmium and mercury may increase the risk of anaemia and cancer as well as cardiovascular, lung and neurological diseases.

Scientists around the world are currently researching links, especially between heavy metal exposure and cancer – arsenic, for example, is considered a carcinogen.^[25-29] Lead and mercury are particularly dangerous for children, as these heavy metals can affect the nervous system and impair brain development.^[10]

What are common heavy metal poisoning symptoms?

Heavy metal poisoning symptoms can be vary from person to person. It also depends on which heavy metal your body has absorbed, how, in what quantities and over what period of time.

Heavy metal poisoning symptoms: what are they?

Acute heavy metal poisoning is often very severe and can lead to kidney and liver failure, circulatory shock and damage to the central nervous system. Typical heavy metal poisoning symptoms – and a case for the doctor – include:

• severe abdominal and limb pain
• fatigue, nausea and vomiting
• irritated respiratory tract

Take acute cadmium poisoning, for example. If you inhale a critical amount of cadmium, this triggers coughing, headaches, fever and confusion. Over the course of a few hours or days, in severe cases, a life-threatening pulmonary oedema (an accumulation of fluid in the lungs) can develop. If you get cadmium salts in your digestive system, symptoms include abdominal pain, nausea, vomiting and diarrhoea.^[31]

What are typical chronic heavy metal poisoning symptoms?

Signs of chronic heavy metal poisoning often include:

• abdominal pain, headache and aching limbs
• diarrhoea, vomiting and nausea
• tiredness, sleeping problems and feelings of weakness
• skin changes (eczema)
• symptoms of paralysis

Sometimes, people might rush from doctor to doctor and not be able to get a diagnosis of heavy metal poisoning. In one case in the United States, after numerous inconclusive tests, the doctors came to the conclusion that their patient’s favourite coffee spoon was partly made of lead and had gradually led to lead poisoning.^[32]

How does our body get rid of heavy metals?

Our body can usually cope with small amounts of potentially toxic substances. The liver and kidneys, in particular, ensure that heavy metals are gradually excreted from the body through our urine and stool, but also through sweat, for example.

However, sometimes, heavy metals accumulate in our bones and organs for years. We therefore absorb them faster than we can excrete them, so that over time there is a build-up. This means they can then damage cells and block enzymes – this is how lead, for example, damages our nervous system and blood formation.^[21]

What foods help remove heavy metals from the body?

If you want to help your body absorb as few heavy metals as possible from food and air and eliminate them effectively, make sure you do not develop a nutrient deficiency! For example, studies show that the body absorbs more lead from food when it is deficient in zinc, calcium and iron. The mineral selenium is also involved in eliminating heavy metals.^[21-24]

How can I test myself for heavy metals?

A heavy metal test can detect traces of heavy metals in your urine and give you an initial indication of whether a particular heavy metal is present in your body in excessive amounts – and thus whether there are hidden sources of pollutants in your environment.

If a test reveals that you have significantly high levels of one or more heavy metals, seek medical advice. Doctors can advise you, carry out further tests – for example, blood tests – and, if necessary, refer you to therapy.

Is heavy metal poisoning reversible?

In the case of heavy metal poisoning, doctors mainly treat the sometimes life-threatening symptoms such as kidney, liver and nerve damage and anaemia. Affected people must also eliminate the cause of the poisoning – for example, dispose of the lead coffee spoon that has poisoned them for years. In the case of less severe heavy metal poisoning, our body is usually able to eliminate the harmful substances on its own.

To prevent our bodies from passing further heavy metals from our digestive tract or blood into our organs, gastric lavage or haemodialysis (blood washing) are forms of treatment that are considered in very severe cases.^[22]

What is chelation therapy?

If there are large amounts of a toxic heavy metal in the body, chelation therapy is the treatment option of choice. Those affected take chelate complexes, which bind heavy metals to themselves, so that the body can eliminate them much faster.^[33]

However, these chelate complexes do not distinguish between good and bad metals. Trace elements such as copper, selenium and zinc are also excreted from the body, which can lead to mineral deficiency symptoms. Doctors therefore usually administer additional mineral supplements with magnesium, selenium and copper, among others. Medical guidelines recommend chelation therapy only in cases of severe poisoning with heavy metals.^{[22, 31]}

In alternative medicine, chelation therapy is supposed to detoxify the body from heavy metals and help against circulatory disorders and arteriosclerosis. According to scientific experts, however, chelation therapy is not an effective form of treatment for these health conditions – and may even have dangerous side effects.^[34–40]

How can I avoid heavy metal poisoning?

Heavy metals are part of our planet; they are in the air we breathe, in the soil and especially in the food we eat. So you won’t be able to avoid them completely. But there are a few tricks you can live by to reduce your intake of heavy metals in everyday life.^{[2, 4, 41, 42]}

Six tips for less heavy metal exposure in everyday life

1. Wash fruit and vegetables carefully. By doing so, you can often significantly reduce heavy metal content on the food. Be especially careful with vegetables that are more heavily contaminated – especially, herbs and leafy vegetables such as spinach and lettuce.
2. Do not eat too many wild mushrooms. Experts recommend eating no more than 250 grammes of wild mushrooms such as chanterelles and porcini per week. Mushrooms are usually cultivated and contain virtually no heavy metals.
3. Watch out for flaxseed. If you eat flaxseed regularly, it is better to buy finely broken rather than crushed flaxseed – crushing makes it easier for the body to absorb the cadmium it often contains.
4. Rice often contains relatively high levels of arsenic. As a parent, you should give your children rice products such as rice porridge, rice milk and rice cakes only in moderation and wash rice before cooking.
5. Lead in game. If game is shot with lead-containing ammunition, an increased amount of lead is found in the meat. If you come from a hunter’s household and consume a lot of game, you should check your lead levels.
6. Pregnant women, breastfeeding mothers and small children should reduce their consumption of foods with elevated heavy metal levels – particularly,  mercury-containing saltwater fish (such as tuna, halibut, eel). Children are still particularly sensitive to heavy metals such as lead and mercury. You can find out more about the ideal diet during pregnancy and breastfeeding in our Health Portal.

What is heavy metal poisoning – at a glance

What are heavy metals?

The heavy metals lead, cadmium, chromium, cobalt, copper, nickel, mercury and zinc pose a threat to our health to different extents. Arsenic, a semi-metal, and aluminium, a light metal, are similar.

How do people come into contact with heavy metals?

Toxic heavy metals are produced, for example, by emissions from coal-fired power plants and by the abrasion of brakes and tyres in road traffic. They enter the atmosphere and are deposited in water, soil and plants. Lead, mercury, cadmium and arsenic, among others, find their way into our food, especially in leafy vegetables, rice, wild mushrooms and fish.

Why are heavy metals problematic?

Heavy metals can lead to acute and chronic heavy metal poisoning – although this is rare nowadays. However, a heavy metal can also accumulate in the body over a long period of time, thus promoting cardiovascular diseases and cancer, among other things.

How can heavy metal poisoning occur?

Today, acute heavy metal poisoning still occurs occasionally in industrial accidents – especially, when metal dust or similar substances are handled.

In everyday life, there are rare individual cases of heavy metal poisoning – cases involve, for example, lead-containing ceramic glazes and broken old mercury thermometers or with Asian Ayurvedic medicines that contain large amounts of lead and mercury.

How is heavy metal poisoning treated?

In cases of heavy metal poisoning, doctors treat heavy metal poisoning symptoms such as pain, paralysis and organ damage, among others. In cases of severe poisoning, heavy metals are eliminated through chelation therapy.

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