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Health Concerns About Nickel

Orthodontic braces

About nickel

Nickel is a very hard metal that is quite reactive but rapidly forms a protective oxide surface which means that it is considered corrosion-resistant. It can also exist as a number of different compounds such as nickel oxide, nickel sulphate and nickel carbonyl which have different oxidation states (from 0 to +4) and as a variety of isotopes.

Nickel in the environment comes from volcanic dust and soil, the industrial processing of nickel and production of stainless steel and also from the combustion of fuel oil and municipal incineration.   

Nickel is used in many industrial and consumer products including:

  • Stainless steel which contains approximately 60% nickel
  • Nickel copper alloys often used in coins such as the  US five-cent coin and the 1 and 2 Euro coins
  • Rechargeable batteries
  • Magnets, electric guitar strings, microphone capsules and other electronic devices
  • Taps/faucets and valves used for domestic plumbing and in tea and coffee machines can contaminate the supply
  • The manufacture of peanut butter, hydrogenated vegetable oils and vegetable shortening
  • Jewellery
  • Prosthetics and dental applications (see below)
  • Cigarette smoke and
  • Is also naturally high in chocolate, soy products, nuts, oats, peas, beans and lentils.



Nickel: Carcinogen

The US Department of Health and Human Services, the International Agency for Research on Cancer (IARC) and the US Environmental Protection Agency (EPA) have all classified metallic nickel as a probable carcinogen and nickel compounds and nickel dust as being known carcinogens.

Nickel is routinely used to induce cancer in laboratory animals and and it is known to suppress natural killer (NK) cells which combat cancerous cells and viruses and also to lower T4 and T8 lymphocyte counts. This may also lead, according to Dr David Eggleston D.D.S., to the development of infectious and autoimmune diseases (J. Prosthetic Dent, 1984, 51; 5)

Nickel refinery workers have a significantly increased risk of mortality from respiratory cancers such as laryngeal, lung or nasal cancer. However, occupational exposure to nickel sulphate and nickel carbonyl have been shown to be the most toxic forms with nickel carbonyl combining emitting highly toxic carbon monoxide gas in addition to nickel.


Contact dermatitis and nickel

Voted 'Allergen of the Year' by the American Contact Dermatitis Society in 2008 at least one in every ten women is sensitised to nickel and some estimates claim as many as one in five.

Nickel sensitisation is more common in women than men probably because of higher rates of ear and body piercing rather than any gender difference in susceptibility to sensitisation. There is some evidence of an increased genetic susceptibility to nickel sensitisation in families with a history of atopy (asthma, eczema, etc) or contact dermatitis. 

Sensitisation typically involves initial prolonged contact with a nickel alloy such as earrings or prosthesis and the reaction tends to be local although with repeated exposure, it can spread to other locations, particularly the hands and feet causing blistering and itching. In one study, over 10% of Korean dental technicians had become sensitised to many of the metals they handled on a daily basis - including nickel. Contact reactions to nickel can also cause irritation of the eyes.

Inherited deficiencies in some liver detoxification enzymes may predispose to susceptibility to developing sensitivities to metals and other chemicals. Once an individual has become sensitised to nickel, much lower concentrations are needed to elicit a response and among sensitised individuals a direct relationship between nickel exposure level and the severity of the dermatitis has been found.  

In recognition of this fact, many earrings are now made using nickel-free alloys and the European Union has regulated the amount of nickel which is allowed in products which come into contact with human skin although the 1 and 2 Euro coins can exceed this amount.


Respiratory effects of nickel

A variety of cancerous and noncancerous respiratory problems such as chronic bronchitis and emphysema have been associated with those exposed to airborne nickel compounds such as welders and foundry workers. However, exposure to a variety of other toxic metals such as uranium, iron, lead, and chromium often makes it difficult to separate out the health effects of nickel.  

About a third of the nickel retained in the lungs is absorbed into the blood and the toxicity of nickel in the respiratory tract appears to be related to the solubility of the nickel compounds involved and to the exposure concentration.   


Nickel and reproduction

Studies in mice and humans have shown adverse structural changes in the testes, increases in sperm abnormalities and a decrease in sperm motility, sperm count and fertility with exposure to nickel and nickel compounds. 

Animal studies also show prenatal exposure to nickel results in less live births, reduced body and organ weight and increased neonatal mortality. This has led to concerns that the developing organism may be particularly sensitive to nickel toxicity during gestation and lactation.


Other health problems and nickel

Whilst the primary target of nickel toxicity appears to be the respiratory tract following inhalation exposure, the immune system is affected by inhalation, oral or dermal exposure, and the reproductive system and development by oral exposure. 

Most absorbed nickel is thought to be excreted in the urine and not to bioaccumulate to any great extent in animals. However, a National Health and Nutritional Examination Survey of hair found mean nickel levels of 0.39 ppm, with 10% of the population having levels four times the mean either due to excessive exposure or an inability to excrete nickel.

Other health problems associated with nickel toxicity are: 

  • Low blood pressure
  • Gastrointestinal upset including nausea, vomiting, cramps and diarrhoea
  • Neurological symptoms such as giddiness, headache and weariness
  • Haemorrhage (spontaneous bruising) and oedema
  • Cardiovascular problems and 
  • Fibromyalgia and backache.


Dental uses of nickel

Dental uses of nickel based alloys include the stainless steel wires used in orthodontic braces, the stainless steel crowns used to restore severely decayed baby teeth, cobalt chrome removable partial dentures, some of the the alloys used to make porcelain-fused-to-metal bridges and crowns and titanium alloys used in implants.

Nickel based alloys are cheaper than those containing a high percentage of precious metals and Dr Hal Huggins DDS MS estimates that half of US dentists insert nickel-based crowns and bridges but charge the patient for, and make an insurance claim for, precious metal alloy. Occasionally too the dentist may be unaware and the laboratories involved may be passing off nickel alloys as high precious metal. In total, Dr Huggins estimates that more than 75% of the crowns placed today contain nickel. In particular, a lot of crowns placed in the mid 1980s tended to be high nickel content because the cost of precious metal alloys had become prohibitive. 

Whilst nickel is toxic in and of itself it also produces a battery effect especially when placed in a mouth alongside dental amalgam fillings and gold restorations. After all, nickel is used in batteries for its ability to produce electric currents in combination with other metals! Nickel in the mouth can produce high negative or positive currents and can also enhance the release of mercury vapour from dental amalgam fillings. The production of currents just centimetres from the brain and controlling endocrine glands may have profound health implications. 

There also appears to be cross-reactivity with those that have been sensitised to mercury becoming reactive to gold and for those that are either gold or mercury sensitive, a high percentage will also react to nickel.

However, once dental amalgam fillings are removed, reactivity to gold and mercury declines significantly and three-quarters of subjects report significant long-term health improvements after 2 years, however reactivity to nickel remains (Dr Hal Huggins, It's All In Your Head).

There is also plenty of anecdotal evidence of recovery from a variety of illnesses after removal of nickel containing dental work. In particular, there appears to be a relationship between nickel crowns and breast cancer in women. And a high percentage of multiple sclerosis (MS) and lupus (SLE) sufferers test positive to nickel and/or inorganic mercury using the MELISA allergy test.


"Nickel is rapidly gaining a reputation for its toxicity, too. Most partial dentures are made of nickel. Approximately 80% of crowns use nickel, even "porcelain" crowns. Braces usually are nickel. Stainless steel is usually nickel alloy. Nickel compounds have been unequivocally implicated as human respiratory carcinogens in epidemiological studies of nickel refinery workers, and there appears a relationship between nickel crowns and breast cancer in women."

Dr Thomas Levy, M.D. 


When eczema sufferers were tested (using an antigen specific LST-test) 87% showed positive reactions to mercury and to nickel, whilst 38% and 40% respectively tested positive to gold and palladium. After removal of the LST positive dental metals from the mouth, 82% obtained relief of symptoms within 10 months.

The amount of nickel released from nickel-chromium dental alloys is strongly influenced by the content of chromium and beryllium in the alloy. If the alloy contains less than 15% chrome the surface of the metal is not rendered passive and the addition of even small amounts of beryllium in the alloy also promotes increased nickel ion release. 


Final thoughts on nickel

Some biological dentists think that there is no place for the use of metals in restoring the mouth and when it comes to single tooth restorations, ceramic and plastic alternatives are available. However that does just leave the option of plastic dentures to replace missing teeth and they definitely have their limitations too.

If you are suffering from some sort of chronic health condition, it is worth considering the possibility that the metals used in your mouth may be a significant contributory factor. For more information please refer to Chronic Fatigue, ME and Fibromyalgia: The Natural Recovery Plan book, the article and associated videos Muscle Testing Dental Restorations or watch Muscle Testing Dental Amalgam Restorations.


Further resources

You might also be interested in the following: 

Read button

About Fatigue Syndromes

Chromium: The Good and The Ugly

Cobalt Toxicity

Biological Dentistry

Research: Mercury, Toxic Metals and Cancer

The Role of Toxic Metals in Fatigue Syndromes

An Open Letter Explaining Fatigue Syndromes

The Causes of Cancer

What Causes Gum Disease?

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Lead: The Silent Killer


Or for all media use the Search facility at the top of the page


Health concerns about nickel: Article summary

This article looks at the adverse health effects of nickel including contact dermatitis, cancer, respiratory illness and the effects on male fertility and foetal and early life development. The dental uses of nickel-containing alloys and the possible health effects are examined.


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The Natural Recovery Plan Newsletter May 2011 Issue 17. Copyright Alison Adams 2011. All rights reserved
Dr Alison Adams Dentist, Naturopath, Author and Online Health Coach

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