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© Endeavour College of Natural Health endeavour.edu.au 1
NMDF121
Session 23
Toxic Metals
Naturopathic Medicine Department
© Endeavour College of Natural Health endeavour.edu.au 2
Topic Summary
• Toxic Metals
– Qualities and categories
• Arsenic
• Cadmium
• Mercury
• Nickel
• Aluminium
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Toxic Metals
• Not usually consumed by or found in humans
• Difficult to excrete from the system
• Interfere with body function
• Categories:
• Sources of contamination
• Methods of toxicity
• Symptoms of toxicity
• High risk populations
• Treatment of toxicity
• Prevention
© Endeavour College of Natural Health endeavour.edu.au 4
Arsenic
http://commons.wikimedia.org/w/index.php?title=Special%3ASear
ch&redirs=0&search=arsenic&fulltext=Search&ns0=1&ns6=1&ns1
2=1&ns14=1
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Arsenic
• Aside from conjuring images of toxicity, evidence is accumulating that arsenic is an essential element
• Appears to facilitate use of methyl groups such as SAMe
• Regulates cellular signal transduction pathways including insulin
• Through activation of the G-protein-coupled receptor S1P1, influences cell proliferation and differentiation
(Gropper and Smith 2013)
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Sources
• Content depends on soil & pollution
• Weed killers
• Environmental toxin from burning fuel oils and coals
• Small amounts in food such as meats, grains and dairy
• Higher in filtering mollusks, fish and Hijiki seaweed
• Most toxic: inorganic arsenite, trivalent organoarsenicals.
• Less toxic: organic forms, pentavalent, methylated arsenic
compounds
(Agency for Toxic Substances and Disease Registry 2007)
(Food Standards Australia, 2013)
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Arsenic
• Metabolism:
• Organic - little or none in liver
• Inorganic - reduced, methylated or both in liver
• Concentrates in skin, hair, nails
• Excreted mostly via kidneys in urine
• Derivative arsenic trioxide approved treatment of acute promyelocytic leukemia• Exhibits potent antitumor activity
• Promoted complete remission in over 50% of patients
• Has side effects on heart and blood cells(Nicolis 2009)
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Deficiency
• Recommended intake
• Suggested: 12-25 µg
• No tolerable upper limit established(Gropper et al, 2009)
• Deficiency in animals –
– Impairs methionine metabolism
– Decreased SAMe decarboxylase activity
– Decreased taurine production(Uthus 1993)
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Toxicity
• Methods of toxicity:
• May displace phosphorous and phosphates in some
reactions in the body
• Antagonises selenium and iodine (Gropper 2013)
• Symptoms of toxicity:
• Possibly – hair loss, dermatitis, diarrhoea, fatigue,
headaches, confusion, muscle pains, red and white
blood cell problems, neurologic symptoms, and liver
and kidney damage.(Agency for Toxic Substances and Disease Registry 2007)
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Arsenic
• Amounts:
• 7-10ppm in hair analysis
• High risk population:
• Miners, smelters and vineyard workers
• Treatment:
• Dimercaprol (given 24 hours after exposure)
• Can be supported with Vitamin C
• Prevention:
• Avoid sources
© Endeavour College of Natural Health endeavour.edu.au 11
Cadmium
http://commons.wikimedia.org/wiki/
File:Cadmium_nitrate.png
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Sources
• Cigarette smoke – 1 mcg/cigarette, 70% exhaled
• Refined foods and root vegetables
• Water pipes - galvanised
• Coal burning
• Shellfish, sea weeds
• Ceramics, dental materials, storage batteries
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Methods of Toxicity
• Competes with zinc for binding sites disrupting normal function
• May catalyse oxidation reactions
• Symptoms:• Kidney damage
• Cardiac hypertrophy
• Progressive atherosclerosis
• Depressed immunity
• Prostate enlargement
• Bone deformities
• Emphysema
• Anaemia
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Cadmium
• Amounts leading to toxicity:
• Increased absorption with zinc, iron, or calcium
deficiency
• 2ppm in hair analysis
(Bernhoft 2013)
• High risk population:
• Industrial and metal workers, zinc miners, smokers
and passive smokers, diets with refined flours and
sugars (white rice)
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Cadmium
• Treatment:
• EDTA chelation
• High intake of zinc and selenium will prevent further
absorption
• Iron, copper, selenium and Vitamin C will help
elimination
• Prevention
• Minimise exposure
• Ensure adequate zinc levels (15-30mg/day)
• Strengthen kidney function
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Review Questions
1. List common sources of arsenic and cadmium.
2. What are the main functions thought to be
associated with arsenic?
3. Which mineral does cadmium mimic on enzyme
binding sites? Why is this an issue?
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Lead
http://commons.wikimedia.org/wiki/File:Lead.jpg
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Sources
• Batteries
• Solder
• Pottery
• Pigments - cosmetics
• Gasoline
• Paint
• Food – grown near industrial areas
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Methods and Symptoms of Toxicity
• Interferes with calcium, iron, copper, and zinc
• Inactivates metalloenzymes in brain chemistry
• Can react with cell membranes
• Immunosuppressant
• May have some affect on gastrointestinal function
• Symptoms of toxicity:
• Acute – headache, fatigue, muscle pains, anorexia, constipation,
vomiting, pallor, anaemia.
• Low level – affects intelligence, attention span, language and
memory. Insomnia and nightmares, hyperactivity and retardation,
and senility
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Lead
• Amounts:
• 0-30ppm may be normal.
• High risk population:
• Anyone working directly with lead or those working in zinc or
vanadium mining.
• Children and pregnant women.
• Treatment:
• EDTA
• Calcium and vitamin D and C supplementation
• Cysteine and methionine – 250mg twice daily
© Endeavour College of Natural Health endeavour.edu.au 23
Lead
• Prevention:
• Renovation of old houses with lead-based paint
• Do not store food in pottery
• Avoid soldered cans
• Evaluate for lead levels any questionable substances (i.e.
water)
• High amounts of lead has been linked to decreases in
cognitive performance.
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Mercury
http://commons.wikimedia.org/wiki/File:Bille-Hg.jpg
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Sources
• Fungicides and pesticides
• Cosmetics – antibacterial additive
• Dental fillings
• Medicines
• Coal burning
• Fish
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Methods and Symptoms of Toxicity
• Affects the inherent protein structure via damage to cell membranes and inactivation of enzymes
• Immunodepressant
• May interfere with selenium
• Symptoms of toxicity:
• Inhalation – Fever, chills, coughing, and chest pain
• Ingestion – fatigue, insomnia, irritability, anorexia, loss of
sex drive, headache, forgetfulness or poor memory.
Dizziness, tremors, uncoordination, and depression.
• Possible relationship with multiple sclerosis (small trial).
(Attar 2012)
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Mercury
• Amounts leading to toxicity:
• >5ppm hair levels
• High risk population:
• Farmers and those with amalgam fillings
• Treatment:
• Drinking milk – mercury acts on protein in milk
• Vitamin C, selenium, pectin and alginates
• Prevention:
• High fibre diet
• Selenium 100-200mcg
© Endeavour College of Natural Health endeavour.edu.au 28
Mercury• FSANZ advice regarding Mercury:Pregnant women and women
planning pregnancy
1 serve equals 150 grams#
Children (up to 6 years)
1 serve equals 75 grams #
Rest of the population
1 serve equals 150 grams #
2 – 3 serves per week of any fish and seafood not listed below 2 – 3 serves per week of any fish and seafood
not listed in the column below
OR
1 serve per week of Orange Roughy (Sea Perch) or Catfish and no other
fish that week
1 serve per week of Shark (Flake) or Billfish
(Swordfish / Broadbill and Marlin) and no other
fish that week
OR
1 serve per fortnight of Shark (Flake) or Billfish (Swordfish / Broadbill and
Marlin) and no other fish that fortnight
# A 150 gram serve for adults and older children is equivalent to approximately two frozen crumbed fish portions.
A 75 gram serve for children is approximately three fish fingers (Hake or Hoki is used in fish fingers).
Canned fish is sold in various sizes; for example, the snack- size cans of tuna are approximately 95 grams.
If you are in doubt about the type of fish or boneless fish fillets you are buying, ask the retailer and confirm the name of the
fish being supplied. This also applies when eating out.
http://www.foodstandards.gov.au/consumer/chemicals/mercur
y/Pages/default.aspx
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Review Questions
1. List the main sources of mercury and lead.
2. What are the main minerals thought to be affected
by lead? Which system has this been noted to
mostly affect?
3. What is the main mineral known to be affected by
mercury? Which endogenously produced
antioxidant compound is dependent on this
mineral?
© Endeavour College of Natural Health endeavour.edu.au 30
Activity
o Read the following journal article:
Wright, R. O., & Baccarelli, A. (2007). Metals and neurotoxicology. The
Journal Of Nutrition, 137(12), 2809-2813.
https://login.ezproxy.endeavour.edu.au:2443/login?url=http://search.ebscohost
.com/login.aspx?direct=true&db=mdc&AN=18029504&site=eds-
live&scope=site
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Activity (continued)
o Make a dot point summary of the most important factors
under each of the following headings –
• Neurotoxicity of iron and manganese
• Neurotoxicity of arsenic and cadmium
• Neurotoxicity of zinc and copper
• Metal mixtures and neurodevelopment
o Discuss these points in small groups then present a
summary from your group to the class
o Online students discuss in the online forums
© Endeavour College of Natural Health endeavour.edu.au 32
Nickel
http://commons.wikimedia.org/wiki/File:Nick
el.jpg
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Sources
• Plant sources contain higher levels than animal
foods
• Nuts, legumes, grains and chocolate higher levels
• Fruits and vegetables intermediate content
• Fish, milk, eggs lower content
• Used in industry for stainless steel and nickel-
cadmium batteries
• Released into environment when burned(Gropper 2013)
© Endeavour College of Natural Health endeavour.edu.au 34
Function
o The specific function of nickel in humans in not known.
o Some functions that require more research are:
• May be involved with folate and B12 in the metabolism of methionine
• This mineral is also a co-factor of various enzymes and may substitute other minerals such as Cu, Zn and Fe, typically negatively impacting enzyme function
• Enhances activity and stability in the complement system when replacing Mg in the formation of C3 convertase enzyme
(Gropper, 2013)
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Toxicity
• Intense pulmonary and gastrointestinal toxicity.
• Diffuse interstitial pneumonitis.
• Cerebral oedema.
• Antagonises Fe absorption
(Kohlmeier, 2003; Oseicki, 2002)
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Deficiency
• In animals –
• Decreased reproduction
• Depressed growth
• Altered Fe, lipid and CHO metabolism
• Impaired haematopoiesis, probably due to altered iron
metabolism
• Effects on bone and thyroid hormone metabolism
• Daily dosage – 100-260mcg
• Toxic dose - >60mg per day(Kohlmeier, 2003; Gropper 2013)
© Endeavour College of Natural Health endeavour.edu.au 37
Aluminium
http://commons.wikimedia.org/wiki/Fi
le:Aluminium_hydroxide.svg
© Endeavour College of Natural Health endeavour.edu.au 38
Sources• Foods
• Food additives – AlPO4 in processed cheese, Potassium
Alum to whiten flour, Sodium silicoaluminate for free-
flowing salt
• Medicines
• Antacids – Aluminum hydroxide
• Cosmetics
• Cookware – leaching from pots, pans and foil
• Especially with acid foods (tomatoes, rhubarb)
• Increased if cooking with fluoridated water
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Methods of Toxicity
• May interfere with some magnesium functions
• May reduce vitamin levels or bind to DNA
• Associated with weakened gastrointestinal tissue
• Bind pepsin
• Astringent
• May block underarm lymphatics
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Toxicity
• Symptoms:
• Acute – constipation, nausea, anorexia, colic, gastrointestinal irritation, skin problems
• Chronic – muscle twitching, numbness, paralysis, fatty degeneration of kidney and liver
• Hypothesised link to Alzheimer’s and Parkinson’s disease
• Hyperactivity and learning disorders in children
• Amounts:
• Best measured by hair analysis
© Endeavour College of Natural Health endeavour.edu.au 41
Aluminum
• High Risk Population:
• Diets high in refined foods, flours, baked goods, processed cheeses and common table salt
• Those using antacids, antiperspirants or cook with aluminum foil or kitchenware
• Treatment:
• Use chelation therapy (EDTA, desferrioxamine)
• Support with Calcium, Magnesium and zinc
© Endeavour College of Natural Health endeavour.edu.au 42
Aluminum - Research
Aluminium in Over-the-Counter Drugs Risks Outweigh
Benefits?
Over-the-counter antacids are the most important source for human
aluminium exposure from a quantitative point of view. However,
aluminium can act as a powerful neurological toxicant and provoke
embryonic and foetal toxic effects in animals and humans after
gestational exposure. Despite these facts, the patient information
leaflets from antacids that are available OTC show substantial
differences regarding warnings. It seems advisable that all patients
should receive the same information on aluminium toxicity from patient
information leaflets, in particular with regard to the increased
absorption through concomitant administration with citrate-containing
beverages and the use of such antacids during pregnancy.
(Reinke 2003)
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Review Questions
1. List common sources of nickel and aluminium.
2. What are the main functions thought to be
associated with nickel?
3. Which mineral is aluminium thought to interfere
with?
© Endeavour College of Natural Health endeavour.edu.au 44
References
• Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for
Arsenic (Update). U.S. Public Health Service, U.S. Department of Health and Human
Services, Atlanta, GA. 2007.
• Gropper and Smith 2013. Advanced Nutrition and Human Metabolism 6th Ed.
Wadsworth Cengage Learning, USA.
• Kakela, R., Kakela, A. and Hyvarinen, H. (1999) Effects of nickel chloride on
reproduction of the rat and possible antagonistic role of selenium, Comparative
Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology,
123, 27-37.
• Lowe, J. F. and Frazee, L. A. (2006) Update on Prostate Cancer Chemoprevention,
Pharmacotherapy, 26, 353-359.
• Nicolis et al 2009. Arsenite medicinal use, metabolism, pharmacokinetics and
monitoring in human hair. Biochemie.91: 1260-67
• Reinke et al. 2003. Aluminium in over-the-counter drugs: risks outweigh benefits?
Drug Saf. 26: 14; 1011-25
• Uthus and Nielsen 1993. Determination of the possible reuqirements and reference
dose level for arsenic in humans. Scand J Work Environ Health 19 (suppl 1) 137-38
© Endeavour College of Natural Health endeavour.edu.au 45
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