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Heavy Metal Toxicity

January 25, 2012 Written by JP    [Font too small?]

Heavy metal exposure has become an increasingly relevant topic in the modern age. The air we breathe, the food we eat and even the homes we live in are potential contributors to unsafe levels of toxic minerals including cadmium, lead and mercury. Although this is undeniably true, there’s no sense worrying ourselves sick about it. A far more constructive approach is to look for ways to minimize heavy metal exposure, such as the use of air purifiers, safer building materials and water filtration. And, while we’re at it, perhaps we should add a little more garlic to our diets for good measure.

A fascinating new study was published in the December 2011 issue of the journal Basic & Clinical Pharmacology & Toxicology. In it, a group of workers from the car battery industry were treated with either garlic or d-penicillamine – a pharmaceutical chelating agent. All of the study volunteers were characterized as having “chronic lead poisoning”. The primary goal of the research was to compare the ability of the two substances to lower blood lead concentrations or BLCs in the workers’ blood. The garlic supplement used in the 4 week study contained 1,200 mcg of allicin per tablet and was given thrice-daily. Both treatments were found to significantly reduce BLCs. However, the workers treated with garlic also demonstrated various symptomatic improvements including fewer headaches, lower systolic blood pressure and a reduction in irritability. Also of note, the group treated with d-penicillamine reported a higher incidence of side effects. Based on these findings, the authors of the trial concluded that, “garlic seems safer clinically and as effective as d-penicillamine. Therefore, garlic can be recommended for the treatment of mild-to-moderate lead poisoning”.

In addition to the previously mentioned paper, numerous animal studies have also placed a positive light on garlic as a dietary protectant against heavy metal toxicity. Several trials indicate that garlic limits the assimilation and uptake of harmful trace minerals in rats. As importantly, garlic has been shown to hasten the elimination of toxic metals, while simultaneously protecting the kidneys and liver from oxidative damage caused by cadmium, mercury and nickel. This partially explains why the use of garlic in test animals prevents unwelcome changes in blood sugar and lipid levels which can contribute to cardiovascular disease and diabetes.

Paradoxically, one of the most amazing things about garlic is that it may actually assist the body in absorbing more of the minerals that are essential to well being. Two recent experiments inform that eating garlic alongside foods rich in iron and zinc increases the bioavailability of the minerals. I even came across one study which found that consuming garlic together with iron supplements prevents iron-induced oxidative stress. In real world terms, this may allow iron users to derive the maximum benefits of the mineral without the possible downside of increased oxidation.

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

To learn more about the studies referenced in today’s column, please click on the following links:

Study 1 – Comparison of Therapeutic Effects of Garlic and d-Penicillamine (link)

Study 2 – Comparative Study on the Efficacy of Allium Sativum (Garlic) (link)

Study 3 – Protective Effect of Aqueous Garlic Extract Against Lead(link)

Study 4 – Effect of Garlic (Allium Sativum) on Nickel II or Chromium VI (link)

Study 5 – Hepatoprotective Potentials of Onion and Garlic Extracts on (link)

Study 6 – Garlic (Allium Sativum L.) as a Potential Antidote for Cadmium (link)

Study 7 – Effect of Garlic (Allium Sativum) on Heavy Metal (Nickel II and (link)

Study 8 – Promoting Influence of Combinations of Amchur, β-Carotene (link)

Study 9 – Higher Bioaccessibility of Iron and Zinc from Food Grains (link)

Study 10 – Protective Effects of Crude Garlic by Reducing Iron-Mediated (link)

Garlic (AGE) Suppresses LDL Cholesterol Oxidation

Source: J Nutr. 2006 Mar;136(3 Suppl):765S-768S. (link)

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Posted in Alternative Therapies, Diabetes, Heart Health

14 Comments & Updates to “Heavy Metal Toxicity”

  1. Paul F. Says:

    Hi JP,

    Fascinating collection of wonders about garlic!

    The Lord must have been Italian!

    Great job!


  2. JP Says:

    Thank you, Paul! 🙂

    Be well!


  3. JP Says:

    Updated 07/29/15:


    Nutrients. 2015 Jan 14;7(1):552-71.

    Dietary strategies for the treatment of cadmium and lead toxicity.

    Cadmium (Cd) and lead (Pb) are toxic heavy metals that cause adverse health effects in humans and animals. Chelation therapy, the conventional treatment for heavy metal toxicity, is reported to have a number of safety and efficacy issues. Recent studies have shown that dietary supplements play important roles in protecting against Cd and Pb toxicity. This paper reviews the evidence for protective effects of essential metals, vitamins, edible plants, phytochemicals, probiotics and other dietary supplements against Cd and Pb toxicity and describes the proposed possible mechanisms. Based on these findings, dietary strategies are recommended for people at risk of Cd and Pb exposure. The application of these strategies is advantageous for both the prevention and alleviation of Cd and Pb toxicity, as such supplements can be added easily and affordably to the daily diet and are expected to have very few side effects compared to the chelation therapy.

    Be well!


  4. JP Says:

    Updated 07/29/15:


    JPEN J Parenter Enteral Nutr. 2014 Feb;38(2):179-85.

    Beneficial effect of sesame oil on heavy metal toxicity.

    Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissue. Chelation therapy is mainly for the management of heavy metal-induced toxicity; however, it usually causes adverse effects or completely blocks the vital function of the particular metal chelated. Much attention has been paid to the development of chelating agents from natural sources to counteract lead- and iron-induced hepatic and renal damage. Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of proinflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels. Because metal chelating therapy is associated with adverse effects, treating heavy metal toxicity in addition with sesame oil and sesamol may be better alternatives. This review deals with the possible use and beneficial effects of sesame oil and sesamol during heavy metal toxicity treatment.

    Be well!


  5. JP Says:

    Updated 07/29/15:


    Biol Trace Elem Res. 2012 Dec;150(1-3):264-71.

    Lactobacillus plantarum CCFM8661 alleviates lead toxicity in mice.

    Tian F1, Zhai Q, Zhao J, Liu X, Wang G, Zhang H, Zhang H, Chen W.

    Lead causes a broad range of adverse effects in humans and animals. The objective was to evaluate the potency of lactobacilli to bind lead in vitro and the protective effects of a selected Lactobacillus plantarum CCFM8661 against lead-induced toxicity in mice. Nine strains of bacteria were used to investigate their binding abilities of lead in vitro, and L. plantarum CCFM8661 was selected for animal experiments because of its excellent lead binding capacity. Both living and dead L. plantarum CCFM8661 were used to treat 90 male Kunming mice during or after the exposure to 1 g/L lead acetate in drinking water. The results showed oral administration of both living and dead L. plantarum CCFM8661 offered a significant protective effect against lead toxicity by recovering blood δ-aminolevulinic acid dehydratase activity, decreasing the lead levels in blood and tissues, and preventing alterations in the levels of glutathione, glutathione peroxidase, malondialdehyde, superoxide dismutase, and reactive oxygen species caused by lead exposure. Moreover, L. plantarum CCFM8661 was more effective when administered consistently during the entire lead exposure, not after the exposure. Our results suggest that L. plantarum CCFM8661 has the potency to provide a dietary strategy against lead toxicity.

    Be well!


  6. JP Says:

    Updated 09/14/15:


    Curr Cardiol Rep. 2015 Nov;17(11):96.

    EDTA Chelation Therapy to Reduce Cardiovascular Events in Persons with Diabetes.

    The Trial to Assess Chelation Therapy (TACT) was a randomized double-blind placebo-controlled trial enrolling patients age ≥50 years with prior myocardial infarction. TACT used a 2 × 2 factorial design to study ethylene diamine tetraacetic acid (EDTA) chelation and high-dose vitamin supplementation. Chelation provided a modest but significant reduction in cardiovascular endpoints. The benefit was stronger and significant among participants with diabetes but absent in those without diabetes. Mechanisms by which chelation might reduce cardiovascular risk in persons with diabetes include the effects of EDTA chelation on transition and toxic metals. Transition metals, particularly copper and iron, play important roles in oxidative stress pathways. Toxic metals, in particular cadmium and lead, are toxic for the cardiovascular system. This review discusses the epidemiologic evidence and animal and human studies supporting the role of these metals in the development of diabetes and ischemic heart disease and potential ways by which EDTA chelation could confer cardiovascular benefit.

    Be well!


  7. JP Says:

    Updated 1/26/16:


    Environ Monit Assess. 2016 Feb;188(2):86.

    Heavy metal content in various types of candies and their daily dietary intake by children.

    Children are vulnerable to heavy metal contamination through consumption of candies and chocolates. Considering this representative samples (69) of candies and chocolates based on cocoa, milk and sugar were analyzed for selected heavy metals by means of flame atomic absorption spectrometry. The average concentration of Zn, Pb, Ni, and Cd was found to be 2.52 ± 2.49, 2.0 ± 1.20, 0.84 ± 1.35, and 0.17 ± 0.22 μg/g respectively. Results indicate that cocoa-based candies have higher metal content than milk- or sugar-based candies. The daily dietary intake of metals for children eating candies and chocolates was also calculated, and results indicated highest intake of Pb and Zn followed by Ni, Cd, and Cu. Comparison of the current study results with other studies around the globe shows that the heavy metal content in candies and chocolates is lower in India than reported elsewhere. However, to reduce the further dietary exposure of heavy metals through candies and chocolates, their content should be monitored regularly and particularly for Pb as children are highly susceptible to its toxicity.

    Be well!


  8. JP Says:

    Updated 08/13/16:


    Appl Environ Microbiol. 2016 Jun 30;82(14):4429-40.

    Oral Administration of Probiotics Inhibits Absorption of the Heavy Metal Cadmium by Protecting the Intestinal Barrier.

    The heavy metal cadmium (Cd) is an environmental pollutant that causes adverse health effects in humans and animals. Our previous work demonstrated that oral administration of probiotics can significantly inhibit Cd absorption in the intestines of mice, but further evidence is needed to gain insights into the related protection mode. The goal of this study was to evaluate whether probiotics can inhibit Cd absorption through routes other than the Cd binding, with a focus on gut barrier protection. In the in vitro assay, both the intervention and therapy treatments of Lactobacillus plantarum CCFM8610 alleviated Cd-induced cytotoxicity in the human intestinal cell line HT-29 and protected the disruption of tight junctions in the cell monolayers. In a mouse model, probiotics with either good Cd-binding or antioxidative ability increased fecal Cd levels and decreased Cd accumulation in the tissue of Cd-exposed mice. Compared with the Cd-only group, cotreatment with probiotics also reversed the disruption of tight junctions, alleviated inflammation, and decreased the intestinal permeability of mice. L. plantarum CCFM8610, a strain with both good Cd binding and antioxidative abilities, exhibited significantly better protection than the other two strains. These results suggest that along with initial intestinal Cd sequestration, probiotics can inhibit Cd absorption by protecting the intestinal barrier, and the protection is related to the alleviation of Cd-induced oxidative stress. A probiotic with both good Cd-binding and antioxidative capacities can be used as a daily supplement for the prevention of oral Cd exposure.

    IMPORTANCE: The heavy metal cadmium (Cd) is an environmental pollutant that causes adverse health effects in humans and animals. For the general population, food and drinking water are the main sources of Cd exposure due to the biomagnification of Cd within the food chain; therefore, the intestinal tract is the first organ that is susceptible to Cd contamination. Moreover, Cd exposure causes the disruption of the intestinal barrier and further induces the amplification of Cd absorption. The present study confirms that, along with initial intestinal Cd sequestration, oral administration of probiotics can inhibit Cd absorption by protecting the intestinal barrier. A probiotic with both good Cd-binding and antioxidative capacities can be used as a daily supplement for the prevention of oral Cd exposure.

    Be well!


  9. JP Says:

    Updated 09/08/16:


    J Am Coll Cardiol. 2016 May 24;67(20):2411-8.

    Heavy Metals, Cardiovascular Disease, and the Unexpected Benefits of Chelation Therapy.

    This review summarizes evidence from 2 lines of research previously thought to be unrelated: the unexpectedly positive results of TACT (Trial to Assess Chelation Therapy), and a body of epidemiological data showing that accumulation of biologically active metals, such as lead and cadmium, is an important risk factor for cardiovascular disease. Considering these 2 areas of work together may lead to the identification of new, modifiable risk factors for atherosclerotic cardiovascular disease. We examine the history of chelation up through the report of TACT. We then describe work connecting higher metal levels in the body with the future risk of cardiovascular disease. We conclude by presenting a brief overview of a newly planned National Institutes of Health trial, TACT2, in which we will attempt to replicate the findings of TACT and to establish that removal of toxic metal stores from the body is a plausible mechanistic explanation for the benefits of edetate disodium treatment.

    Be well!


  10. JP Says:

    Updated 01/08/17:


    J Neurogastroenterol Motil. 2017 Jan 30;23(1):101-108.

    Irritable Bowel Syndrome and Nickel Allergy: What Is the Role of the Low Nickel Diet?

    Background/Aims: Irritable bowel syndrome (IBS) is characterized by chronic abdominal pain or discomfort accompanied by abnormal bowel movements. In sensitized subjects, ingested nickel (Ni) may induce gastrointestinal symptoms similar to IBS, in addition to typical systemic cutaneous lesions (systemic nickel allergy syndrome [SNAS]). A low nickel diet could improve the systemic manifestations. We evaluated prevalence of nickel allergy in IBS and effects of low Ni diet on (1) gastrointestinal symptoms control, (2) intestinal barrier function, (3) quality of life, and (4) psychological status of patients with IBS and Ni-sensitized patients.

    Methods: Twenty consecutive patients affected by IBS and suspected SNAS underwent intestinal permeability tests. Gastrointestinal symptoms were evaluated using the visual analogue scale before and after 3 months low Ni diet. Subjects with increased intestinal permeability at baseline repeated nuclear examination after the diet.

    Results: The most frequent profile was diarrhea-predominant IBS (8/20). The low Ni diet induced a significant and constant improvement of gastrointestinal symptoms and an equally significant improvement of visual analogue scale. Mean urinary output of ⁵¹Chromium ethylene-diamine-tetra-acetate (⁵¹Cr-EDTA) was 5.91%/24 hr (± 2.08), significantly different from the control group (2.20%/24 hr ± 0.60, P < 0.0001). Conclusion: This pilot study shows that low Ni diet improves gastrointestinal symptoms in patients with IBS and SNAS. Be well! JP

  11. JP Says:

    Updated 03/03/17:


    J Res Med Sci. 2016 Nov 7;21:108.

    A randomized controlled trial on the effects of jujube fruit on the concentrations of some toxic trace elements in human milk.

    BACKGROUND: This study aims to investigate the concentrations of lead, cadmium, and arsenic in the human milk, and to assess the effect of jujube fruit consumption by lactating mothers in reducing the concentration of these heavy metals in their milk.

    MATERIALS AND METHODS: This randomized controlled trial was conducted in 2014 among forty postpartum mothers in Isfahan, the second largest and polluted city in Iran. Mothers were randomized into two groups; the intervention group received 15 g/day of fresh jujube fruit, and the controls received routine care for 8 weeks.

    RESULTS: In the beginning, the concentrations of lead, cadmium, and arsenic were high, without significant difference between groups. The mean (standard deviation) concentrations of lead, cadmium, and arsenic were 29.49 (16.6), 4.65 (3.51), and 1.23 (0.63) μg/L, respectively. The smoothed empirical distribution of environmental pollutants showed that in both groups the mean values and variance of toxic metals decreased after 8 weeks, with a sharper decline in the intervention group. Quantile regression analysis showed that in the intervention group, lead concentration decreased by 2.54 μg/L at the 90th quintile, and cadmium decreased by 0.19 μg/Lat 75th quintile; without significant change in arsenic level. The corresponding figures were not significant in the control group.

    CONCLUSION: The concentrations of heavy metals were high in human milk, and the consumption of jujube fruit had some beneficial effects in reducing these harmful elements. Pregnant and lactating mothers should be advised to reduce their exposure to environmental pollutants, and consumption of some natural medicinal foods can be useful in reducing the concentration of pollutants in human milk. Because of numerous benefits of breast milk, in spite of the existence of some toxic trace elements, breastfeeding must be encouraged because such contaminants are also found in water and formula. The impact of the current findings on the primary prevention of chronic disease should be determined in future longitudinal studies.

    Be well!


  12. JP Says:

    Updated 03/07/17:


    J Chin Med Assoc. 2017 Mar 2.

    Influence of seafood and vitamin supplementation on maternal and umbilical cord blood mercury concentration.

    BACKGROUND: The purpose of this study was to examine the influence of maternal seafood consumption and vitamin supplementation during pregnancy on maternal and umbilical cord blood mercury (Hg) concentration.

    METHODS: In this study of 145 healthy pregnant women (mean age 28.1±5.2 years), we administered questionnaires, collected paired maternal/umbilical cord blood samples, and measured the anthropometrics of newborns. Blood Hg concentration was assayed by inductively coupled plasma-mass spectrometry.

    RESULTS: Sixty-one of these women (42.1%) used vitamins >3 times/wk prenatally. Seventy-eight of our study participants (61.9%) reported eating higher amounts of seafood during pregnancy. We found a strong correlation (r=0.76, p<0.001) between Hg levels in the paired maternal/umbilical cord blood samples. Mothers with high seafood consumption had a 2.91-fold greater risk (adjusted odds ratio 2.91, 95% confidence interval: 1.04-8.15, p=0.042) of high Hg levels (>5.8 μg/L). However, mothers whose prenatal vitamin intake was >3 times/wk were found to have low Hg levels (≤5.8 μg/L) (adjusted odds ratio 0.06, 95% confidence interval: 0.01-049, p=0.008).

    CONCLUSION: High seafood consumption was an independent risk factor for high maternal Hg level, while vitamin supplementation was a protective factor. Further study is needed to investigate the specific effect of vitamins on Hg level.

    Be well!


  13. JP Says:

    Updated 05/09/17:


    Environ Int. 2017 May;102:200-206.

    High selenium exposure lowers the odds ratios for hypertension, stroke, and myocardial infarction associated with mercury exposure among Inuit in Canada.

    BACKGROUND: Selenium (Se) has been reported to protect against the neurotoxicity of mercury (Hg). However, the effect of Se against Hg on cardiovascular diseases remains unclear. Inuit living in the Arctic have high exposure to both Se and Hg through their marine mammal and fish rich traditional diet.

    OBJECTIVE: To characterize the co-exposure of Hg and Se among Inuit in Canada and to assess the associations between Hg, Se and cardiovascular health outcomes, including stroke, hypertension, and myocardial infarction (MI).

    METHODS: Data was collected from the International Polar Year Inuit Health Survey (IHS) conducted in 2007 and 2008. Blood Se and Hg were measured, and self-report cardiovascular health outcomes were collected through a questionnaire interview from 2169 adults aged 18 and above.

    RESULTS: The mean age was 42.4years, and 38.7% of the participants were male. The geometric means (GM) of blood Se and total Hg were 319.5μg/L and 7.0μg/L, respectively. The crude prevalence of heart attack, stroke and hypertension were 3.55%, 2.36%, and 24.47% respectively. Participants were categorized into 4 exposure groups according to blood Hg (high: ≥7.8μg/L; low: <7.8μg/L), and Se (high: ≥280μg/L; low: <280μg/L). The odds ratio (OR) of cardiovascular outcomes were estimated using general linearized models. Results showed the low Se and high Hg group had a higher prevalence of cardiovascular disease (OR=1.76 for hypertension, 1.57 for stroke, and 1.26 for MI. However, the prevalence was decreased in both the high Se and low Hg group (OR=0.57 for hypertension, 0.44 for stroke, and 0.27 for MI) and the high Se and high Hg group (OR=1.14 for hypertension, 0.31 for stroke, and 0.80 for MI).

    CONCLUSIONS: The high Se and low Hg group had the lowest prevalence of cardiovascular outcomes, except for stroke. These results provide evidence that Se may exhibit a protective effect against Hg on cardiovascular disease.

    Be well!


  14. JP Says:

    Updated 04/15/18:


    BMJ Open. 2018 Apr 12;8(4):e020533.

    Associations between blood cadmium levels and cognitive function in a cross-sectional study of US adults aged 60 years or older.

    OBJECTIVES: The relationship between cadmium exposure and cognition has been well studied in children. However, the association between environmental cadmium exposure and cognitive function has not been researched extensively in older adults. Our goal was to evaluate the association between cognitive function and blood cadmium levels in US adults aged 60 years or older.

    DESIGN: A cross-sectional study.

    SETTING: The US National Health and Nutrition Examination Survey (NHANES).

    PARTICIPANTS: A total of 2068 adults aged 60 years or older who completed four cognitive assessment tests and blood cadmium detection in two waves of NHANES (2011-2014).

    MAIN OUTCOME MEASURES: Cognitive assessment was conducted by household interview or at a Mobile Examination Center (MEC) using the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) Word List Learning Test, the CERAD Word List Recall Test, the Animal Fluency Test and the Digit Symbol Substitution Test (DSST). We created a composite cognitive z-score to represent global cognitive function.

    RESULTS: The median blood cadmium concentration in the study participants was 0.35 µg/L, and the IQR was 0.24-0.56 µg/L. In linear regression analyses, adjusting for demographics, behaviour and medical history, blood cadmium as a continuous variable was inversely associated with the composite z-score (μg/L, β=-0.11, 95% CI -0.20 to -0.03). Similarly, there was a significant association between quartiles of blood cadmium and composite z-score, with somewhat lower scores in the upper quartile of exposure (blood cadmium ≥0.63 µg/L) compared with those in the lower quartile of exposure (blood cadmium <0.25 µg/L) (μg/L, β=-0.14, 95% CI -0.25 to -0.03), and there was a trend by quartiles of blood cadmium (P<0.0001).

    CONCLUSIONS: Our findings suggest that increased blood cadmium is associated with worse cognitive function in adults aged 60 years or older in the USA.

    Be well!


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