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Relationship of Intake of Plant and Animal Protein, and Longevity

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On 8/24/2019 at 1:47 AM, mccoy said:

Ron, I'm going to ask the lab guys here about the SOP for Cadmium, it is not a routine analysis in my place. Whatever the reports, I think I should go on with that. I eat amounts of cacao powder comparable to those of the Kuna Indians.

I saw that the Mayo Clinic does a blood test for chronic exposure:



It's not routine, but I've tested myself twice in the last couple of years (also for lead and mercury) and the results are as good as they can be. Since I've been eating copious amounts of cacao powder and cacao nibs for close to a decade, I'd say that the danger may be a bit overblown.

I've switched to cacao nibs, since they contain a bit less cadmium, according to consumerlab, plus they are less processed (retain more fat). I like their crunchiness with a banana and a walnut or two in the morning 🙂

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Elements Testing – Why Sample Type Matters!



Cadmium Urinary cadmium is the best indicator of long term exposure to this toxic element.  Cadmium is concentrated in the kidneys and urinary levels represent cumulative cadmium exposure over the long term (it has a 30 year half-life).[10] Whole blood cadmium levels reflect recent exposure within the last 50 days.[11] [12] Only about 0.01-0.02% of the total body cadmium burden is excreted every day because it accumulates primarily in the kidneys.[13] Serum is a poor indicator of exposure because cadmium in the bloodstream binds to red blood cells, with erythrocyte concentrations 20 times higher than serum.[14]

* * * * *


A patient ceased smoking cigarettes (high source of cadmium) 6 months ago, but was a habitual smoker for 20 years. Whole blood and serum would potentially show low cadmium levels while urine tests high for cadmium. This is because whole blood represents recent cadmium intake and serum is a poor indicator of cadmium burden, while urine indicates long term cadmium exposure.

* * * * *

[10] Nordberg GF, Jin T, Kong Q, et al. Biological monitoring of cadmium exposure and renal effects in a population group residing in a polluted area in China. Sci Total Environ. 1997;199:111-4.

[11] Lauwerys R, Roels H, Regniers M, et al. Significance of cadmium concentration in blood and in urine in workers exposed to cadmium. Environ Res. 1979;20:375-91.

[12] Järup L, Rogenfelt A, Elinder CG, et al. Biological half-time of cadmium in the blood of workers after cessation of exposure. Scand J Work Environ Health. 1983;9:327-31.

[13] ATSDR (2008) Toxicological profile for cadmium. Agency for Toxic Substances and Disease Registry, Atlanta, GA

[14] Friberg L, Piscator M, Nordberg GF, Kjellstrom T. Cadmium in the Environment. 2nd ed. Cleveland, OH: CRC Press; 1974.



Testing for Toxic Elements: A Focus on Arsenic, Cadmium, Lead, and Mercury (2011)




Background and Potential Sources of Exposure

Cadmium is often found near sites of metal mining and refining, production and application of phosphate fertilizers, waste incineration, and disposal.33 Occupational exposure to cadmium is a serious consideration in the battery, smelting, and electroplating industries. Soluble forms are transported easily by water and accumulate in aquatic organisms. Cadmium may also be transported as a particle or vapor for long distances in the atmosphere, depositing on soil and water surfaces. Cadmium binds strongly to organic matter where it is immobilized in soil and taken up by plant life and agricultural crops.

Since tobacco leaves accumulate cadmium from the soil, regular use of tobacco-containing products is a common route of human cadmium exposure. The U.S. national geometric mean blood cadmium levels for non-smoking adults is 0.47 μg/L, whereas the mean in smokers is approximately twice as high, at 1.58 μg/L.34 Smoking is estimated to at least double the lifetime body burden of cadmium exposure. For non-smokers, human exposure to cadmium is largely through the consumption of shellfish, organ meats, lettuce, spinach, potatoes, grains, peanuts, soybeans, and sunflower seeds.35

Toxicity and Toxicokinetics

In the workplace, inhalation is the primary route of exposure where 5%–35% of inhaled cadmium is absorbed into the blood depending on its form, site of deposition, and particle size. If the cadmium penetrates to the alveoli, it is estimated that there is 100% absorption into the blood.36 Approximately 1–3 μg cadmium is absorbed per pack of cigarettes. Following ingestion, it is estimated that 5%–10% of cadmium is absorbed.1 In diets with low iron, calcium, or protein, it is possible that more cadmium is absorbed. Dermal exposure is not a typical human health concern as cadmium does not penetrate the skin barrier.

Upon absorption in the blood, cadmium binds to albumin and is transported to the liver. Cadmium-induced liver damage increases hepatic enzymes.33 Metallothionein (MT), a low molecular weight metal-binding protein, binds cadmium where it is either stored in this conjugated form in the liver or transported to the kidney. Once filtered through the renal glomerulus, the cadmium-MT complex is reabsorbed in the proximal tubules and degraded to release free cadmium. It is this reactive cadmium ion that contributes to renal tubular toxicity while accumulating in the cortex of the kidney.37 Renal tubule damage is a hallmark of cadmium toxicity and is reflected in increased concentrations of biomarkers such as β2-microglobulin. Glomerular damage may follow with corresponding increased levels of albumin and transferrin.38

The concentration of cadmium in the kidney is reflected in urinary levels. As such, urine testing can be used as a marker of long-term cadmium exposure. Elimination of cadmium is very slow, as the elimination half-life of cadmium is up to 20 years.

Urinary cadmium concentration of less than 2.5 μg/g creatinine has been considered to represent safe exposures.39 However, recent studies have identified increased risk to cancer and mortality following chronic, low-level cadmium exposure.40 Cancers primarily of the lung, but also prostate, kidney, and pancreas have been documented. A disease unique to cadmium exposure, Ouch Ouch disease, is characterized with severe osteomalacia and osteoporosis from the long-term consumption of cadmium-contaminated rice but has implications for aging patients in general who are diagnosed with osteoporosis.37,41


24 hour urinary samples are used in many population studies,  for example:

Environmental exposure to cadmium and risk of cancer: a prospective population-based study. (2006)





Cadmium is a ubiquitous environmental pollutant, which accumulates in the human body such that 24-h urinary excretion is a biomarker of lifetime exposure. We aimed to assess the association between environmental exposure to cadmium and cancer.


We recruited a random population sample (n=994) from an area close to three zinc smelters and a reference population from an area with low exposure to cadmium. At baseline (1985-89), we measured cadmium in urine samples obtained over 24 h and in the soil of participants' gardens, and followed the incidence of cancer until June 30, 2004. We used Cox regression to calculate hazard ratios for cancer in relation to internal (ie, urinary) and external (ie, soil) exposure to cadmium, while adjusting for covariables.


Cadmium concentration in soil ranged from 0.8 mg/kg to 17.0 mg/kg. At baseline, geometric mean urinary cadmium excretion was 12.3 nmol/day for people in the high-exposure area, compared with 7.7 nmol/day for those in the reference (ie, low-exposure) area (p<0.0001). During follow-up (median 17.2 years [range 0.6-18.8]), 50 fatal cancers and 20 non-fatal cancers occurred, of which 18 and one, respectively, were lung cancers. Overall cancer risk was significantly associated with a doubling of 24-h cadmium excretion (hazard ratio 1.31 [95% CI 1.03-1.65], p=0.026. Population-attributable risk of lung cancer was 67% (95% CI 33-101) in the high-exposure area, compared with that of 73% (38-108) for smoking. For lung cancer, adjusted hazard ratio was 1.70 (1.13-2.57, p=0.011) for a doubling of 24-h urinary cadmium excretion, 4.17 (1.21-14.4, p=0.024) for residence in the high-exposure area versus the low-exposure area, and 1.57 (1.11-2.24, p=0.012) for a doubling of cadmium concentration in soil.


Historical pollution from non-ferrous smelters continues to present a serious health hazard, necessitating targeted preventive measures


Mayo Clinic Laboratories   Cadmium, 24 Hour, Urine



There has been a lot of discussion about cadmium in previous threads.   Dean Pomerleau has commented on the  interaction of various  minerals in terms of absorption etc.

See also:

Zinc and Multi-Mineral Supplementation Should Mitigate the Pathogenic Impact of Cadmium Exposure



Zinc Intake Is Associated with Lower Cadmium Burden in US Adults




Dietary antioxidant and anti-inflammatory intake modifies the effect of cadmium exposure on markers of systemic inflammation and oxidative stress (2014)



Toxicity of cadmium and its health risks from leafy vegetable consumption (2017)



Dietary Cadmium Intake and Sources in the US (019)




Edited by Sibiriak
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Thanks Sibiriak - excellent post & references.

So we know that cacao nibs have less cadmium than powder (but amounts vary by brand/source) and that adequate calcium, iron, zinc & magnesium intake also helps to mitigate cadmium risk.

I was able to find some information online regarding cadmium in some popular brands but not of one I was interested in on Amazon (Sevenhills Wholefoods, organic, raw); I am not a member of ConsumerLabs.  Essential Living Foods Cacao nibs which have been tested and reported 'low' (according to quick searching) in cadmium are approx 4x the price of the Sevenhills brand.

Having said that, assuming your calcium/iron/zinc/magnesium intake is adequate, I wonder if the benefits for cacao nib consumption outweighs the risk; especially if you are not willing to have (urine) testing for cadmium done?  (just curious of opinions on this)


Edited by Clinton
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One countermeasure we've been discussing is supplementing zinc, which competes with Cd to be  bound. I'm not sure about cacao nibs, except individual preferences. The cost in terms of epicatechin content is higher than in unprocessed cacao powders, nibs can also be higher in fats. 

Urinary analyses are much easier than analyzing blood samples.

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My guess, based on what I have read, such as the Mayo Clinic link above discussing blood concentration values, is that both a blood test and a urine analysis would show increased cadmium levels if there were any. Blood test are the only way to evaluate for acute exposure (urine test doesn't appear to be useful for that) while urine test appears to be better detecting exposure in the more distant past, in cases where no exposure has occurred recently, which is not my case.

Sibiriak's post above also appears to support blood tests to determine long term cadmium exposure:

3 hours ago, Sibiriak said:

Since tobacco leaves accumulate cadmium from the soil, regular use of tobacco-containing products is a common route of human cadmium exposure. The U.S. national geometric mean blood cadmium levels for non-smoking adults is 0.47 μg/L, whereas the mean in smokers is approximately twice as high, at 1.58 μg/L.34 Smoking is estimated to at least double the lifetime body burden of cadmium exposure. For non-smokers, human exposure to cadmium is largely through the consumption of shellfish, organ meats, lettuce, spinach, potatoes, grains, peanuts, soybeans, and sunflower seeds.

At this point, I am comfortable eating my cacao nibs, since despite long-term ingestion, my cadmium blood levels are below measurable (LabCorp). At my next annual physical, I'll do a urine test for cadmium, too.

Edited by Ron Put
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Thanks Ron,

If/when you get a urine test results for cadmium I’d be interested to know your results.

I’m thinking that going with raw organic nibs and more than adequate minerals discussed above that 1-2 TBSP per day is likely safe and beneficial - that’s the amount I’m planning to add to my smoothie(s)


Edited by Clinton
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It sounds wise.

I am not due for a physical until next year, but based on my blood results, I am not really concerned (I first tested myself for cadmium a couple of years ago). In fact, I probably often ate a bit more than 40g of cacao nibs back then, since in the last few months I have been trying to reign in my protein intake, which is kind of high -- all plant based, but still.... Cacao nibs add a lot of my fat and protein calories.

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  • 2 weeks later...

Some  excellent  previous threads dealing with cacao etc.  that are  well worth reviewing:

Cadmium contamination in cacao products    By BrianMDelaney, May 19, 2014

Composition and Health Implications of Various Chocolate Products  By Dean Pomerleau, November 9, 2015

So Why Don't We Brew Our Chocolate? By Dean Pomerleau, November 10, 2015

Kuna Indians and the cacao heaven  By mccoy, March 16, 2017


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