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mccoy

Heavy metals in foods

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This issue has already been discussed in relation to single contaminats, but now I'd like to open a thread where a complete summary of the state of the art is at our convenient disposal.

I'm going to start with the EFSA threshold values, any other references are welcome. It may take some time but at the end I'd like a concise table or spread sheet which we can use as a practical decisional reference, complete with foods high in the contaminants and so on. And hopefully complete with references on lab tests.

Below is the very start of this collection, kg obviously refers to kg of bodyweight. mg is micrograms and ug is micrograms =0.001 milligrams = 1*10-6 grams (one millionth of a gram).

 

image.png.99afe5cb9e87c3fbc1c64d4bf9ab9a45.png

Edited by mccoy

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This is a useful reference for inorganic arsenic (iAs),  but it is just a regulatory content in the food itself, not a dietary UTL

Sci Total Environ. Author manuscript; available in PMC 2017 Mar 1.
 
Published in final edited form as:
PMCID: PMC5303536
NIHMSID: NIHMS845305
PMID: 28065543

Mitigating dietary arsenic exposure: Current status in the United States and recommendations for an improved path forward

 

image.png.93759d6a86eda23c4202dd1bfc970f3e.png

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There seems to be no accepted threshold for iAs. It maybe be inferred from some dose-response estimates, based upon iAs in drinking water

Quote

Arsenic in Bangladesh has attracted much attention since recognition in the 1990s of its wide occurrence in well-water in that country. Since this time, significant progress has since been made and the number of people exposed to arsenic exceeding the Bangladesh drinking-water quality standard has decreased by approximately 40%. Despite these efforts, it was estimated that in 2012 about 19 million and 39 million people in Bangladesh were still exposed to arsenic concentrations above the national standard of 50 μg/L and the WHO provisional guideline value of 10 μg/L respectively (5). In a highly affected area of Bangladesh, 21.4% of all deaths in the area were attributed to arsenic levels above 10 μg/L in drinking-water (6). A similar dose-response function has been found in other parts of Bangladesh, and these these results have been combined with national survey data to estimate an annual death toll of nearly 43 000 (7). The US National Research Council has noted that as many as 1 in 100 additional cancer deaths could be expected from a lifetime exposure to drinking-water containing 50 μg/L (8).

The symptoms and signs caused by long-term elevated exposure to inorganic arsenic differ between individuals, population groups and geographical areas. Thus, there is no universal definition of the disease caused by arsenic. This complicates the assessment of the burden on health of arsenic.

 

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Hi Mccoy!

My bloodwork on heavy metals always shows zero in every category but one:  Arsenic.  My nephrologist looked into it:  inorganic As is toxic; apparently not so for organic As.  My nephrologist did more tests on my serum As:  The As is organic.

I don't know which vegetable is the source of it -- but I'm not worried.

  🙂

    --  Saul

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Mccoy,  apart from your high cocoa powder intake,  are there any foods you are particularly worried about in terms of heavy metals?

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Hi Sibiriak!

Another factor to take into account regarding heavy metal absorption from food, is that older adults are supposed to be less efficient in absorbing heavy metals from foods.  This suggests that the problem is at its maximum in children.

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14 hours ago, Sibiriak said:

Mccoy,  apart from your high cocoa powder intake,  are there any foods you are particularly worried about in terms of heavy metals?

Sibiriak, not specifically, but there may be some concealed sources of contaminants, even from tap water or mineral water. Since the damage from heavy metals toxicity may by far exceed the damage of a slightly inappropriate food regimen, then it makes sense to be a little concerned.

My next line of action will be analyses of urinary heavy metals or heavy metals metabolites. They are all available at the local lab and, although not really cheap, the price, about US$ 27 per metal, except Mercury which costs US$ 33, it may be worth to rule out a chronic state of contamination. Collecting a urine sample is very easy and delivering it to the lab on our way to work in the morning is almost effortless.

One doubt of mine is the metabolization of such metals, the ideal would be to have a marker of long term exposure like it happens in urinary Cadmium, but that needs to be investigated for every single metal.

Maybe this article was already posted in another thread.

 

Quote

 

Is Urinary Cadmium a Biomarker of Long-term Exposure in Humans? A Review

The publisher's final edited version of this article is available at Curr Environ Health Rep
This article has been corrected. See Curr Environ Health Rep. 2016 October 26; : .
 
See other articles in PMC that cite the published article.
 

Abstract

Cadmium is a naturally-occurring element, and humans are exposed from cigarettes, food, and industrial sources. Following exposure, cadmium accumulates in the kidney and is slowly released into the urine, usually proportionally to the levels found in the kidneys. Cadmium levels in a single spot urine sample have been considered indicative of long-term exposure to cadmium; however, such a potentially exceptional biomarker requires careful scrutiny. In this review, we report good to excellent temporal stability of urinary cadmium (intraclass correlation coefficient 0.66–0.81) regardless of spot urine or first morning void sampling. Factors such as changes in smoking habits and diseases characterized by increased excretion of proteins may produce short-term changes in urinary cadmium levels. We recommend that epidemiologists use this powerful biomarker in prospective studies stratified by smoking status, along with thoughtful consideration of additional factors that can influence renal physiology and cadmium excretion.

 

 

Edited by mccoy

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20 hours ago, Saul said:

Hi Mccoy!

My bloodwork on heavy metals always shows zero in every category but one:  Arsenic.  My nephrologist looked into it:  inorganic As is toxic; apparently not so for organic As.  My nephrologist did more tests on my serum As:  The As is organic.

I don't know which vegetable is the source of it -- but I'm not worried.

  🙂

    --  Saul

Saul, I'm going to have my urine analyzed, probably the tests will detect only inorganic metals.

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Urinary Arsenic also seems to be an indicator of long-term exposure to such a metal. The excerpts below, from the mayo clinic site, also would explain the relatively high As amounts in Saul's blood: it's probably due to his regular consumption of fish.

Also, urinary As, not serum As seems to be a better indicator of exposure:

Quote

 

Because arsenic is excreted predominantly by glomerular filtration, analysis for arsenic in urine is the best screening test to detect arsenic exposure.


 

 
 
 
 
Quote

Interpretation new-info-icon.png

Normally, humans consume 5 to 25 mcg of arsenic each day as part of their normal diet; therefore, normal urine arsenic output is less than 35 mcg arsenic per gram creatinine (<35 mcg/g). When exposed to inorganic arsenic, the urine output may be above 1,000 mcg/g and remain elevated for weeks. After a seafood meal (seafood contains a nontoxic, organic form of arsenic), on the other hand, the urine output of arsenic may be above 200 mcg/g, after which it will decline to under 35 mcg/g over a period of 1 to 2 days.

Exposure to inorganic arsenic, the toxic form of arsenic, causes prolonged excretion of arsenic in the urine for many days.

 

Urine excretion rates above 1,000 mcg/g indicates significant exposure. The highest value observed at Mayo Clinic was 450,000 mcg/L in a patient with severe symptoms of gastrointestinal distress, shallow breathing with classic "garlic breath," intermittent seizure activity, cardiac arrhythmias, and later onset of peripheral neuropathy.

Cautions new-info-icon.png

Consumption of seafood before collection of a urine specimen for arsenic testing is likely to result in a report of an elevated concentration of arsenic found in the urine, which can be clinically misleading.

 

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Another complicacy of urinary metal analyses is that sometimes they are normalized by g/cr or grams of creatinine, that is, urine dilution/concentration.

My hypothesis though is that this unit might not be appropriate in vegetarians or vegans who consume no creatine at all and surely not in athletes who take creatine supplements.

 

Edited by mccoy

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Hi McCoy!

I forgot to mention:  When my bloodwork is checked for heavy metals, my nephrologist also has them checked a urine sample for heavy metals.

Happily, my medical insurance pays for it --it's part of my semi-annual blood/urine sampling.

  --  Saul

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Lucky you, Saul, even if I decided to upgrade my insurance, it would only pay for the most trivial blood or urine parameters.

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I asked the lab for details, they said that the results of urinary heavy metals tests are in micrograms/g creatinine, that means that I'll have to wait for a while before testing myself since I've been taking creatine until about 20 days ago. Vegetarians and bodybuilders who take creatine have an abnormally elevated urinary creatinine concentration, so the results would under evaluate the real urinary concentration of heavy metals. Also, I'll have to update the table of thresholds to these more commonly used metrics.

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I just updated the table with some data from the ACGIH 2014 booklet (they are strictly used for workers). Some metals like lead are usually measured in blood, some like As are measured without any creatinine normalization, whereas others like Cd are normalized. some are not cited at all.

image.png.5cabb7b219e84611855235655c4edc02.png

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Any suggestions regarding what to do when one finds they have a high level of lead in the blood?

Two months ago I began having unusual swings in blood pressure, blood sugar, body temp, etc. followed by acute problems with constipation, peripheral neuropathy, night sweats,  poor sleep, fatigue, very poor balance, altered taste and hearing loss.  Some of which was due to an ear infection which cleared up with antibiotics.  But after much searching for the lingering problems I think I have the answer, a blood lead level of 45 mcg/dL.  I had the blood test repeated a second time with the phlebotomy and testing done by different places and got similar results.  I'm looking for a physician experienced in treating lead poisoning and leaning towards requesting the prescription drug chemet which is an oral DMSA chelation therapy.  Having a genetic neuromuscular disease with significant overlap of symptoms with lead poisoning complicates things somewhat and makes me think aggressive treatment is prudent.  For the moment I've suspended consumption of things somewhat notorious for lead contamination such as tea, cacao, spices and most supplements along with activities such as welding, machining and electronics each of which might be a source of exposure.  I'm hoping to borrow or buy equipment so I can scan most everything I consume and interact with to learn the nature of my current exposures but don't know much about this yet.

Edited by Todd Allen

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Sorry to hear this, Todd. I wonder how you got this concentration? Old water pipes? Environment? Soldering? 

I can't imagine it's all from  food source, but it's still good that you are eliminating the potential culprits.

I know nothing about lead poisoning, but according to this, increase your garlic and cilantro consumption:

https://www.theepochtimes.com/the-two-best-herbs-for-lead-poisoning_1957074.html

And definitely see a knowledgeable professional.

Edited by Ron Put

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1 hour ago, Ron Put said:

Sorry to hear this, Todd. I wonder how you got this concentration? Old water pipes? Environment? Soldering?

We put in a 5 stage reverse osmosis water filter which claimed high efficiency of lead removal several years ago which has been the source of most of my water for drinking and cooking ever since.  I'm looking for ways to try and identify current exposures and if there are tests that can show how much of the exposure is recent.

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21 hours ago, Todd Allen said:

We put in a 5 stage reverse osmosis water filter which claimed high efficiency of lead removal 

Maybe that's the source of the lead?  Perhaps the filter is polluted?

Sorry to hear about your problem.

  --  Saul

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26 minutes ago, Saul said:

Maybe that's the source of the lead?  Perhaps the filter is polluted?

We monitor the performance of the filter with a TDS/EC meter.  This doesn't tell us what's in the water but we can see the dramatic drop compared to unfiltered water and see it creeping up and know it is time to install fresh cartridges.  I'd like to test the filtered water for lead along with everything else I ingest but I'd be surprised if it is a significant source of lead.

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21 hours ago, drewab said:

There may be something said for sweating out lead via sauna use.

I don't have a sauna but have for nearly 3 years been taking a nightly extremely hot bath and typically drop 4 to 6 lbs which I expect is on par with the amount people typically sweat out in a sauna session.  I had some urine and blood tests for several common toxins, most were negligible such as arsenic, mercury and cadmium.  Tin was above average but not in the toxic range.  My baths are in unfiltered water and while one isn't supposed to be able to absorb lead through the skin I wonder if it would rise up in the steam and be absorbed through the lungs? 

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