Chlorella detoxification/chelationChelation of simultaneously-administered lead in mice. Very promising from a preventative standpoint:
Int Immunopharmacol. 2003 Jun;3(6):889-900.
Protective effects of Chlorella vulgaris in lead-exposed mice infected with Listeria monocytogenes.
Chlorella vulgaris extract (CVE) was examined for its chelating effects on the myelosuppression induced by lead in Listeria monocytogenes-infected mice...
Treatment with CVE, given simultaneously or following lead exposure, restored to control values the myelosuppression observed in infected/lead-exposed mice and produced a significant increase in serum colony-stimulating activity...
Evidence that these protective effects of CVE are partly due to its chelating effect was given by the changes observed in blood lead levels. We have observed in the group receiving the CVE/lead simultaneous exposure a dramatic reduction of 66.03% in blood lead levels, when compared to lead-exposed nontreated control. On the other hand, CVE treatment following lead exposure produced a much less effective chelating effect. CVE treatments for 3 or 10 days, starting 24 h following lead exposure, produced a reduction in blood lead levels of 13.5% and 17%, respectively, compared to lead-exposed nontreated controls. The significantly better response observed with the simultaneous CVE/lead administration indicates that the immunomodulation effect of CVE plays an important role in the ability of this algae to reduce blood lead levels. In this regard, additional experiments with gene knockout C57BL/6 mice lacking a functional IFN-gamma gene demonstrated that this cytokine is of paramount importance in the protection afforded by CVE. The antibacterial evaluation measured by the rate of survival demonstrated that, in face of a 100% survival in the control group composed of normal C57BL/6 mice, which are resistant to L. monocytogenes, we observed no protection whatsoever in the IFN-gamma knockout C57BL/6 mice treated with CVE and inoculated with L. monocytogenes.
Ability to reduce blood and tissue levels of lead in mice:
Food Chem Toxicol. 2008 Sep;46(9):3147-54. Epub 2008 Jul 19.
Chlorella vulgaris up-modulation of myelossupression induced by lead: the role of stromal cells.
In this study, Chlorella vulgaris (CV) was examined for its chelating effects on the ability of bone marrow stromal cell layer to display myeloid progenitor cells in vitro in lead-exposed mice, using the long-term bone marrow culture (LTBMC)...
Mice were gavage treated daily with a single 50mg/kg dose of CV for 10 days, concomitant to continuous offering of 1300ppm lead acetate in drinking water...
Monitoring of lead poisoning demonstrated that CV treatment significantly reduced lead levels in blood and tissues, completely restored the normal hepatic ALA levels, decreased the abnormally high plasma ALA and partly recovered the liver capacity to produce porphyrins. These findings provide evidence for a beneficial use of CV for combination or alternative chelating therapy to protect the host from the damage induced by lead poisoning.
Chlorella encourages fecal excretion of lead in mice:
Note: This study used
Parachlorella beyerinckii, an algae in the same order as Chlorella vulgaris. This plant was re-identified based on new genetic information and a paper from 2004; it is unclear if other studies and supplements before and since have made this distinction, or if the actions would be different to any degree.
Toxicol Ind Health. 2009 Sep;25(8):551-6.
Parachlorella beyerinckii accelerates lead excretion in mice.
The effect of Parachlorella beyerinckii CK-5, previously identified as Chlorella vulgaris, on gastrointestinal absorption of lead was investigated in mice. Female ICR mice aged 7 weeks were orally administered lead acetate solution at doses of 20 mg and 40 mg of lead per mouse, with or without 100 mg of P. beyerinckii powder (BP). The mice were bred for 24 hours. The amount of lead excreted in feces within 24 hours, and the lead levels of the blood, liver and kidney were analyzed by atomic absorption spectrometry. The percentage of total fecal excretion in mice administered BP increased by 27.7% in 20 mg lead administered mice and 17.2% in 40 mg lead administered mice in comparison to control mice, respectively. On the other hand, the lead levels of the blood, liver and kidney of BP-administered mice at 24 hours after lead administration were 48-63% lower as compared with those of control mice. The lead adsorption ability of BP and the pepsin non-digestive residue of BP (dBP) were investigated in vitro. One hundred mg of BP and dBP could adsorb 10.6 mg and 6.0 mg of lead in a 20 mg per 10 mL of lead solution, respectively. The lead absorption abilities of BP and dBP were considered to contribute to the prevention of gastrointestinal absorption of lead and the promotion of the excretion of lead. These results suggested that BP treatment might be useful in animals and humans exposed to lead.
Chlorella reduced cadmium accumulation in the liver:
J Med Food. 2008 Sep;11(3):479-85.
Protective effects of Chlorella vulgaris on liver toxicity in cadmium-administered rats.
Forty rats were randomly divided into one control and three groups treated with 10 ppm Cd...
Therefore, this study suggests that C. vulgaris has a protective effect against Cd-induced liver damage by reducing Cd accumulation and stimulating the expression of MT II in liver. However, the details of the mechanism of C. vulgaris on liver toxicity remains to be clarified by further studies.
Chlorella accelerates excretion of cadmium only through inhibition of absorption; it must be co-administered with the Cd to have a significant effect:
Nutr Res Pract. 2009 Summer;3(2):89-94. Epub 2009 Jun 30. (full text PDF)
Effect of Chlorella vulgaris intake on cadmium detoxification in rats fed cadmium.
Absorbed Cd is eliminated through MT [metallothonein] from the organism mainly via urine. The amount of Cd excreted daily in urine is, however, very small: It represents only about 0.005-0.01% of the total body burden which corresponds to a biological half-life for Cd of about 20-40 years. MT has attracted attention as a protein possibly related to metabolism and detoxification of heavy metals because it has lower affinity to the essential metal zinc but high affinity to toxic heavy metals such as Cd and Hg...This showed that chlorella intake have the possibility for enhancing synthesis of metal binding MT-like proteins by capturing absorbed heavy metals in the body. Accordingly, if chlorella intake facilitates urinary Cd excretion by the above mentioned mechanism, it would be helpful in the detoxification of Cd.
...
Urinary cadmium concentration was not affected by dietary chlorella intake. Several studies presented that simultaneous intake of Cd and chlorella facilitated urinary Cd excretion and this finding resulted from inhibition of absorption but not from facilitation of excretion. And a few studies presented that, when renal Cd-MT form was increased, urinary Cd excretion was facilitated. Because MT concentration in kidney was somewhat increased by chlorella intake, but not observably (Table 7), its concentration did not lead to increase urinary Cd excretion. Based on above explanation, if simultaneous intake of chlorella and Cd did not happen, Cd was already accumulated in the body and chlorella supplementation could not promote Cd excretion via urine.
Much has been made of this study because the chlorella approximately doubled the amount of Hg excreted in urine and feces. However, there was no appreciable decrease in the amount absorbed into body tissue, because the excreted Hg was still only 4.2% of the injected dose. In the in vitro study, only 6.6% of the MeHg was absorbed by dBP (type found in the intestine) over 16h, meaning that chlorella has almost no ability to prevent GI absorption. The authors propose the possibility that long-term use might have a more significant effect than the 24 hour single-dose study, but it's clear that chlorella isn't as effective at excreting mercury as cadmium and lead.
J Toxicol Sci. 2010;35(1):101-5. (full text PDF)
The influence of Parachlorella beyerinckii CK-5 on the absorption and excretion of methylmercury (MeHg) in mice.
Chlorella (Parachlorella beyerinckii CK-5), previously identified as Chlorella vulgaris CK-5, is a unicellular green algae that has for many years been used as a nutritional supplement. In order to investigate the effects of methylmercury (MeHg) detoxification by Chlorella, we examined the absorption and excretion of MeHg in mice. Female C57BL/6N mice were randomly divided into three groups of five, and were housed in metabolism cages. Mice were orally administered MeHg chloride at doses of 5 mg (4 mg Hg)/kg body weight with or without 100 mg/mouse of P. beyerinckii powder (BP), and were assigned to either a MeHg group or MeHg + BP group, accordingly. Twenty-four hr after oral administration, feces and urine were collected, and blood, liver, and kidney samples were obtained. Total mercury contents in the samples obtained were determined using an atomic absorption method. The amounts of Hg excreted in feces and urine of the MeHg + BP group were increased nearly 1.9 and 2.2-fold compared with those of the MeHg group. On the other hand, blood and organ Hg levels were not significantly different between two groups. These results suggest that the intake of BP may induce the excretion of Hg both in feces and urine, although it does not affect MeHg absorption from the gastrointestinal tract. The effect of BP on the tissue mercury accumulation may become evident in a long-term experiment.
This abstract was truncated, but it indicates that mice were able to effectively absorb dietary iron when fed varying doses of chlorella, suggesting that it does not chelate this metal. Indeed, references in the few free full-text articles mentioned only Cd, Zn, Cu, Pb, and Hg:
Kitasato Arch Exp Med. 1991 Dec;64(4):193-204.
Effect of chlorella on rats with iron deficient anemia.
In order to determine effects of iron deficiency on the living body, rats were given the iron deficient diet (Group 1, iron content, 0.32mg/100g), the complete diet added with iron (Group 5, iron content, 32.5mg/100g), the diet added with 1% chlorella (Group 2, iron content, 2.2mg/100g), the diet added with 5% chlorella (Group 3, iron content, 7.4mg/100g), or the diet added with 10% chlorella (Group 4, iron content, 13.9mg/100g). For the first 30 days, rats of all groups were given the iron deficiency diet to make them iron deficient, and were subsequently given the respective diet during the next 30 days to observe various changes in the conditions of rats...
Rats of Groups 3, 4 and 5 fed with the diets containing certain amounts of iron rapidly recovered, while the recovery of those of Group 2 fed with less iron content diet was delayed.
Finally, LEF's
heavy metal toxicity page lists two references for human studies of heavy metal excretion:
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In a report to the General Meeting of the Pharmaceutical Society of Japan on an early study in animals, Ichimura (1973) reported that chlorella (8 grams daily) increased elimination of cadmium: threefold in feces and sevenfold in urine. Other researchers from Japan showed that chlorella helped detoxify uranium and lead (Horikoshi et al. 1979).
Ichimura, S. Report. General meeting of the Pharmaceutical Society of Japan, Hokuriku Branch, Toyoma City, Japan, October 27, 1973.
Horikoshi, T., Nakajima, A., and Sakaguchi, T. Uptake of uranium by various cell fractions of Chlorella regularis. Radioisotopes 1979 Aug; 28(8): 485-8.There are a couple referenced studies left to get that aren't indexed by pubmed, but I believe they present only similar findings.
It seems that chlorella is effective at chelating lead and cadmium when co-administered. The lack of iron chelation is disappointing, as it might compensate for chlorella's high iron content. Also disappointing is the dearth of current human data, but I'll hazard the effects should be largely applicable to humans; the chelation is an action of metallothionein (MT)-like proteins in the algae cell which are active even in water.