London Clinic of Nutrition
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Heavy Metals

Heavy metals are toxins that we come into contact with on a daily basis due to the increasing contamination of our food and water supply, and the air we breathe.



Exposure to heavy metals has been linked to many chronic health conditions including autoimmunity, ME, cancer, neurological diseases and developmental problems in children.

What are heavy metals?

Heavy metals are, by definition, metals of high relative density or atomic weight. Some heavy metals are seen to be beneficial or harmless in appropriate doses, such as zinc, cobalt and iron, whereas others are highly toxic. These include mercury, lead, chromium (in its hexavalent form), cadmium and arsenic. Aluminium is often grouped into this category, where as it is in fact a light metal, although still toxic and capable of causing harm to health.

All of these heavy metals appear to have a strong affinity for sulphur and bind, via thiol groups, to create sulphur-metal bonds. These bonds can then inhibit the enzymes that control metabolic reactions, causing DNA damage and deterioration in human health with wide ranging symptoms and consequences throughout the body including the respiratory, digestion, immune and central nervous systems. Heavy metals are also found in the placenta during pregnancy, and in the mother’s breast milk, impacting the health of the baby during pregnancy and beyond.

How are we exposed to heavy metals?

• Lead – found in many places including exhaust fumes and paints (thankfully now banned), industrial waste, batteries and water supply from lead pipes. Exposure mainly occurs through inhalation of lead-contaminated dust particles, in crystal and ceramic containers, cosmetics – namely lipsticks, and ingesting lead-contaminated food and water.

• Mercury – mercury that has been released into the air from factories, as well from pesticides, has permeated our soils and waterways. Many fish are contaminated with mercury, with larger fish further up the food chain, such as tuna and swordfish, more saturated than smaller fish, such as sardines and anchovies. Many of us are also exposed to elemental mercury from amalgam fillings in our teeth. The vapour given off by the elemental mercury is highly lipophilic and absorbed through the lungs as well as tissues lining the mouth. Other sources include cosmetics and vaccines. It is essential that all people with amalgam filling have these out at some point soon in their life as Mercury is considered either the first or second most toxic element in existence and finds its way into the tissues.

• Cadmium – used in alloys, pigments and batteries, plus it has been found in toy jewellery. Exposure tends to come predominantly from cigarette smoke and through food such as vegetables, organ meats and shellfish, plus through emissions from contaminated industries such as mining and smelting. It is very difficult to remove from the body because it has a long half-life of 10-20 years.

• Arsenic – several arsenic-containing compounds have been used to manufacture pesticides and wood preservatives. Arsenic-based drugs are used to treat certain tropical diseases and in veterinary medicine to treat parasites. Recently, arsenic trioxide has been approved for use in the treatment of leukemia. Several million people are chronically exposed to arsenic in countries like Bangladesh, India, China, Mexico, and Taiwan, where the ground water is highly contaminated. Arsenic also finds its way into our diets through the intake of rice, and children under five are not recommended to consume rice milk for this reason.

• Chromium – hexavalent chromium is a toxic industrial pollutant that enters the air, water and soil from industries such as metal processing, chromate production and stainless steel welding.

Symptoms of heavy metal toxicity

Symptoms are varied and dependent on the level and duration of exposure, including…

  • Headaches
  • Memory loss
  • Poor attention span
  • Diminished intelligence
  • Fatigue
  • Ataxia
  • Numbness and tingling
  • Muscle weakness
  • Tremor
  • Loss of peripheral vision
  • Hearing loss
  • Encephalopathy
  • Lung inflammation
  • Skin rashes and dermatitis
  • Nausea, vomiting and diarrhoea
  • Gum and mouth inflammation
  • Kidney disorder
  • Gastrointestinal bleeding
  • Anaemia
  • Cancer
  • Diabetes
  • Autoimmune disease

Detoxification of heavy metals from the body

When considering heavy metal detoxification, it is first important to mention glutathione, because it plays a crucial part in the body’s ability to detoxify harmful substances. Glutathione is an intra-mitochondrial antioxidant found inside every cell and in highest concentrations in the liver. Glutathione is used extensively in the body, mopping up free radicals and binding with toxins, such as heavy metals, for excretion via the liver and in urine. It can easily become depleted if demand exceeds supply, and if there is insufficient glutathione then the body will be less able to deal with heavy metal exposure, and harmful levels will accumulate. Depletion of glutathione is linked to neurodegenerative, immune, cardiovascular and liver disease, plus cystic fibrosis and accelerated ageing – all are indicative of glutathione depletion and suggest the need to increase levels.

So how do we get more glutathione? Or more importantly, how do we get more reduced glutathione, which is the form we need for cell protection? Reduced glutathione is made available to the body in 3 ways…

1. De novo glutathione synthesis – a process that converts the amino acid cysteine into glutathione. Availability of cysteine is therefore crucial.
2. Regeneration of oxidised (damaged) to reduced glutathione – oxidised glutathione naturally pairs with available glutathione in the cell, returning the oxidised glutathione back to reduced glutathione.
3. Recycling of cysteine from conjugated glutathione, ready for further glutathione synthesis.

Our approach

Using the functional medicine framework allows us to improve the body’s ability to adapt to a toxic world, through a broad system-wide approach. We combine industry-leading nutrition and functional medicine expertise, alongside the latest testing, so we can attend to all your health needs. Only your practitioner will be able to determine the most suitable test for you following an initial consultation.

Get in touch

Speak to a member of our enquiry team who can assist in matching you with the most suitable practitioner for your needs. The quickest and easiest way to speak with us is to call on 020 3666 2618.

Written by Emma Rushe and Oliver Barnett

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