| Note: cross-posted from unbossed
Introduction
The researchers, from Peking University's School of Public Health, and the Beijing Center for Disease Prevention and Control, say their study "demonstrates...that even a low melamine intake <0.2 mg/kg of body weight per day increases the risk for the development of nephrolithiasis." Nephrolithiasis, also known as urinary tract stone disease, strikes 10 percent of Americans over their lifetimes. It is considerably more common in adults than children, but the number of cases in children has been rising. Exposure to melamine is one of several possible causes.
Melamine is a cheap industrial chemical compound used in the manufacture of plastics, adhesives and other products. In order to maximize profits, unscrupulous Chinese firms mixed melamine, which tests can mistake for protein, with wheat and rice glutens and milk used in manufacture of baby formula, pet food and numerous other products for human and animal consumption. Authorities have linked melamine to the deaths of thousands of American pets in 2007, and to half a dozen deaths of Chinese infants in 2008.
How we got here
After melamine was discovered in the human food chain, through melamine contaminated glutens in animal feed, officials from the FDA, USDA, Centers for Disease Control, Environmental Protection Agency and Department of Homeland Security established regulatory limits for the chemical in human food, announced in an October 3, 2008 news release. But, for infant formula, the regulators said they could not identify "any level...that would not raise public health concerns."
Many interpreted this as "zero tolerance" for melamine in baby formula. They were wrong.
An FDA official would later reveal that the agency had, in fact, been allowing up to 250 parts per billion of melamine in formula (NYTimes). But, consumers were unaware that melamine had been found in domestic formula until November 25, 2008. That's when the Associated Press reported that it had obtained test results from the FDA under the Freedom of Information Act. According to that and later articles by AP, the tests showed that FDA had been sitting on data showing that some samples of formula had trace amounts of melamine or related chemicals called analogues. All of the positive samples, a small percentage of the total, were below 1 ppm. But, the subterfuge created a public relations firestorm. FDA further fanned the flames of consumer outrage by trying to withhold the identities of producers of contaminated samples.
Where we are now
On November 28, the FDA issued revised regulations setting a new limit of 1 ppm melamine in formula - a level conveniently higher than the levels found in samples. That number, FDA said, was derived from an assumption that 100% of the diet were contaminated at a level of 1.26 ppm of melamine," which the FDA equated to a daily intake of 0.063 mg/kg bw/d. FDA rounded 1.26 to 1.00 to "provide an additional margin of safety."
The amounts of melamine allowed by the FDA and other food safety authorities are extremely small compared to the levels that sent thousands of Chinese infants to the hospital in 2008. But, the latest research indicates that even those extremely small amounts of melamine can have adverse consequences for infants who derive all or most of their nutrition from formula. The NOAEL must therefore be even smaller.
Keep in mind that the researchers found that the risk of nephrolithiasis increased with duration of exposure. This implies that health risks are cumulative, perhaps over a lifetime, likely rising as an infant progresses to solid foods that are subject to the higher melamine limit (2.5 ppm) that applies to foods other than infant formula. If that is the case, breast-feeding would provide only temporary protection for children, albeit during the most sensitive period of life.
It's illegal to intentionally add any amount of melamine to food for human or animal consumption. Therefore, some consumers wonder why any amount of melamine is permitted in food. In January 2009, the FDA released a new set of test results revealing that more U.S. formula had tested positive for melamine or one of its analogues, but none exceeded the limit of 1 ppm. FDA attributed these trace amounts to "contact with the chemical during processing and packaging." (News Inferno/Wall Street Journal). Thus, 'unintentional' contamination with melamine is permitted, within established limits; although, one could argue that manufacturers intentionally are using packaging and processes that include melamine.
Where next?
Melamine is used in the manufacture of many products used in homes as well as factories: containers, glazed paper products, utensils, countertops and dishes - including cereal sets designed specifically for children. But, the U.S. government has not moved to restrict the use of melamine products in food handling or to educate the public about the nature of the threat.
Rep. Rosa DeLaura called on FDA to ban any amount of melamine detectable in formula and urged FDA to eliminate melamine from processing and packaging operations. I would add a recommendation that government agencies investigate the environmental impacts of melamine and its analogues, from residual pesticides in soil to home uses of melamine dinnerware.
In the absence of voluntary action by authorities to fully address the melamine threat, it is up to consumers to pressure their representatives in Congress to require appropriate action through legislation and appropriations, to protest to food and formula manufacturers, and to complain directly to regulatory agencies. Early indications from the Obama administration suggest that public health authorities may be more responsive than in past years.
References
The citation, abstract and paper are available at SpringerLink
CITATION
The risk of melamine-induced nephrolithiasis in young children starts at a lower intake level than recommended by the WHO
Gang Li & Shufang Jiao & Xiangjun Yin & Ying Deng & Xinghuo Pang & Yan Wang
Pediatr Nephrol. 2009 Sep 1.
ABSTRACT
Thursday, 08 October 2009
School of Public Health, Peking University, Beijing, 100191, People's Republic of China.
We investigated 683 children with nephrolithiasis and 6,498 children without nephrolithiasis aged < 3 years. Nephrolithiasis was diagnosed by renal ultrasonography in hospitals in Beijing in September/October 2008. In addition, data was collected on current and past formula feeding and on other possible risk factors for nephrolithiasis. Daily intake of melamine per kilogram of body weight was calculated for each individual. In general, the adjusted odds ratios between melamine dose and nephrolithiasis increased with an increasing daily level of melamine intake per kilogram of body weight. The risk of nephrolithiasis also increased with the increasing duration of exposure. Preterm infants, urinary malformation, and parents with a history of urinary stones were independent risk factors. In children exposed to melamine levels < 0.2 mg/kg per day, the adjusted odds ratio expressing the risk for nephrolithiasis was still 1.7 times higher than in those without melamine exposure. These findings suggest that the risk of melamine-induced nephrolithiasis in young children starts at a lower intake level than the levels recommended by the World Health Organization.
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