|Image 1: You better pick the right source of calcium: healthy milk / dairy vs. lead poisoned pills from your local pharmacy or supermarket - you still have the choice.|
What? "Pb" is not the symbol for Calcium in the Periodic Table?
Lead, that stuff nuclear physicists value, because it effectively absorbs radioactive radiation, is one of the most toxic "heavy metals" we are exposed to. And this is by no way a recent discovery. Even in ancient times, people knew about the toxic effect vessels made of this metal had on the water they contained. Back in 1990 E.K. Silberberg summarized the contemporary knowledge about the dangers of environmental lead exposure in a paper for the Environmental Defense Fund as follows (Silberberg. 1990):
[...] epidemiological studies have suggested that central nervous system (CNS) effects in children are observed at the lowest increments of lead exposure [...] Similarly, clinical studies indicate that early exposure to lead produces functionally irreversible damage to the CNS; experimental research demonstrates that this irreversibility may involve failure to remove lead from brain, permanent effects on synaptogenesis; and chelant-induced redistribution of lead from the periphery to the CNS. [...] New data on release of bone stores of lead during physiological conditions of demineralization indicate that mobilization of bone lead adds to in utero exposure of the fetus. Furthermore, postmenopausal demineralization of bone can increase blood lead levels in women by 25%; this raises concern about the potential effects of lead in an aging population and the difficulties in comprehensive exposure assessment.As you may have guessed, time has not affected the dangers or the irreversibility of lead toxicity, so that you would assume that the results of an investigation into the lead content of 27 "commonly used" commercially available calcium supplements should be alarming enough to receive at least some public recognition. After all, it would suffice to read the abstract to be alarmed by the fact that of the calcium supplements Sohaila Rehman and her colleagues from the Pakistan Institute of Nuclear Science Technology analyzed only one out of ten "met the criteria of acceptable Pb levels (1.5µg/daily dose) in supplements / consumer products set by the United States" (Rehman. 2011).
|Figure 1: Lead levels in µg in daily dose of respective calcium supplement; solid red line = acceptable Pb level for calcium supplements, dashed red line = tolerable total daily Pb intake for children <7y, dotted red line = tolerable daily Pb intake for women in childbearing age (data adapted from Rehman. 2011).|
|Figure 2: Lead levels in µg in daily dose of respective calcium supplement; solid red line = acceptable Pb level for calcium supplements, dashed red line = tolerable total daily Pb intake for children <7y (data adapted from Rehman. 2011).|
Note: The results of the study at hand may well explain a) the different outcomes of (controlled) trials and epidemiological studies on the effects of calcium supplements on cardiovascular health and b) the beneficial effects of milk and dairy intake on heart health (Soedamah-Mutuh. 2011). After all, a very recent study that was published in the Journal of Neurotoxicology and Teratology in October 2011, shows that there is a "potential for autonomic dysregulation" that manifests in "significantly greater vascular resistance and reduced stroke volume and cardiac output" in 9-11 year old children even "at levels of Pb typical for many US children" (the exact levels were 1.01µg/dL, cf. Gump. 2011).And as if all that was not enough, the US Food and Drug Administration (FDA) and the glorious Center for Disease Control and Prevention (CDC) would have been aware of the potential of serious chronic lead intoxication from calcium supplements, if they spent more time reading scientific journals than counting the cashflow from the BigPharma companies that finance their bureaucracy. After all, Bourgoin et al. conducted a very similar study back in the 1990s, the results of which the scientists summarize in their abstract as follows (Bourgoin. 1993):
Daily lead ingestion rates revealed that about 25% of the products exceeded the US Food and Drug Administration's "provisional" total tolerable daily intake of lead for children aged 6 years and under.In the Rehmann study it were 16 out of 27 tested calcium supplements (59%) which exceeded this limit. So maybe the "feds" just did not act, because 1 out of 4 is not bad enough? Well, if you look at the individual results in figure 3 (usually I redo graphs, but in this case the original looks just too damn impressive), it is immediately obvious that the averages the scientist report in their abstract, do not reflect the actual potential of lead toxicity from the 70 supplemental sources Bourgoin et al. tested.
|Figure 3: Results of a 1993 large-scale analysis of the lead content of 70! commercially available calcium supplements and milk (my emphasis), the safe exception (from Bourgoin. 1993)|
"Pah, lead!? What doesn't kill you just makes you stronger"
|Image 2: So, calcium supplement with lead are a safe source of dietary calcium, but raw milk is not? (img CounterThink)|
And while the CDC and the FDA could incidentally have missed those papers. They should actually be aware of Proposition 65, which is the common name for California's Safe Drinking Water and Toxic Enforcement Act of 1986 (Dietary Supplement Standard 173, Metal Contaminant Acceptance Levels. NSF International. August 19, 2003). In this paper, of which W.W. Kilgore writes in retrospective that (Kilgore. 1990)
[i]t creates a list of chemicals (including a number of agricultural chemicals) known to cause cancer or reproductive toxicity; [i]t limits discharges of listed chemicals to drinking water sources; [i]t requires prior warning before exposure to listed chemicals by anyone in the course of doing business; [i]t creates a list of chemicals requiring testing for carcinogenicity or reproductive toxicity; and [i]t requires the Governor to consult with qualified experts (a 12-member "Scientific Advisory Panel" was appointed) as necessary to carry out his duties.the proposed Acceptable Intake Level (AIL) for inorganic lead (as extrapolated from animal studies) is 0.5µg/day and thusly 1/3 of the current Californian standards and 1/50 of the FDA allowance of 25µg/day! But hey, who cares? As long as the American citizens are protected from the dangers of raw milk, everything is all right, isn't it?