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BLOG: November 2008
FDA "dosing" melamine for infants and adults
How much of melamine can you take and keep on whistling? In the May last year, the FDA said 0.63mg per kg of body weight, per day. This so called tolerable daily intake (TDI) was determined as 1/100 of the lowest dose causing adverse health effects in a 13-week long rat study. It simply appeared to the FDA that as much lower a dose should be safe.
This month, the FDA informs that it has come to its attention that toxicity of melamine - an organic base with extensive industrial use, found in some fertilizers, and also of limited use in food industry - grows exponentially when combined with its analogues, ammeline, ammelide or cyanuric acid. The main target of their toxicity are the kidneys, which can be damaged by insoluble crystals formed from these compounds.
Consequently, the TDI for the combined intake is reduced tenfold, to 0.063mg/kg/day.
The FDA got less confident with its "it's so low, it must be safe" approach when it came to those most vulnerable: the infants. On October 3rd it stated that it is "currently unable to establish any level of melamine and melamine-related compounds in infant formulas that does not raise public health concerns." In fact, it is still part of their safety and risk assessment dated Nov. 28. 2008.
The reasons are that infant formula is likely to be the main food source for babies; that their kidneys are still underdeveloped, and that contamination with melamine+analogues cannot be excluded.
Nevertheless, just a few days ago, the FDA has issued public statement establishing the official tolerable concentration of melamine alone in infant formulas: 1 part per million (1mg per liter). Of course, there is still no guarantee that melamine analogous won't find their way into babies' bodies, either with the formula, or from some other source.
Cyanuric acid, for instance, is routinely used in bleaches, disinfectants and herbicides; FDA also allows its use in animal foods (as a part of non-protein nitrogen additives) and drinking water.
If, for any reason, one of the analogues find its way into baby's body, the tolerable 1mg/L of melamine transforms into a larger dose of combined toxin. Assuming that baby consumes 1L of formula a day, it may be exposed to concentrations as high as 0.5mg/kg/day of the combined substance, or
several times the official tolerable intake for adults.
Why this escaped FDA's attention is not quite clear. It is possible that it simply decided to set the limit comfortably above the levels of melamine and cyanuric acid (separately) - nearly 0.2 parts per million - that it has just recently detected in infant formulas of two major U.S. manufacturers (Nestle and Mead Johnson).
Not likely? The FDA already showed the utmost care not to disturb the industry, by failing to publicize these findings until after Associated Press did it a few days ago. Also, detected levels are about
ten times higher
than what the FDA estimates can result from contamination during production process; the agency doesn't show as if it cares to find out how the actual levels of melamine in baby foods got to be so much higher.
The third major infant formula producer, Abott Laboratories, acknowledged that its in-house test also detected melamine in their products.
And the melamine story is just a drop in the sea of chemical contamination of our food supply and the environment. If the Chinese haven't magnified melamine's toxic effect by grossly overusing it in food production (primarily milk and dairy products),
we'd still be completely unaware of it.
Exponentially greater magnitude of the combined toxic effect of melamine and its analogues is rather typical for chemical contaminants and toxins. Now, couple that up with hundreds to thousands of them we are exposed to daily, and you'll begin to grasp the seriousness of the problem. Neither the FDA, nor anyone else, has bothered to even approximate possible consequences for the health of general populations. We're on our own, and we need to watch out.
More so considering that current official "safe" intake levels for toxic chemicals are far from reliable, even for individual toxins. Most of them, just like the one for melamine, are based on indirect determination or, rather, guess of what the safe level "should be".
Remember that recent HealthKnot article about bisphenol A toxicity? In determining the "safe" level of intake there, the FDA used 1/1000 of the lowest concentration causing adverse effects in studies on rodents from early 1980's as the official limit for humans (needless to say, those studies were using outdated, insensitive methods by current standards). Recent studies indicate that bisphenol A causes abnormal cell growth at concentrations
20,000 times lower than this FDA's "safe" level.
So, if you want to keep whistling, forget about FDA's "tolerable intakes"; stay away from toxic chemicals as much as you possibly can...