A CHEMICAL that sickened and killed babies in China when it tainted baby formula can also leach off tableware and into food, say Chinese scientists.
However, researchers say that does not prove the compound, called melamine, is harmful to children and adults in the amounts detected when study participants ate hot soup from melamine bowls.
Large doses of melamine — which is used in some types of fertiliser and in resin used to make tableware — killed six babies in China and sent thousands more to the hospital with kidney damage in 2008.
In high enough quantities, melamine can cause kidney stones and other kidney problems in adults as well.
In the new, small study, healthy young adults who ate hot noodle soup from bowls made with melamine resin had higher levels of the chemical in their urine for the next 12 hours.
The study "raises interesting questions about environmental agents that can affect the kidney long term", says Dr Craig Langman, who studies kidney diseases at Northwestern University’s Feinberg School of Medicine in Chicago.
"It does raise some concerns, but it hardly proves anything," says Dr Langman, who was not involved in the new research. "To date, I have great scepticism about the link."
Researchers led by Dr Chia-Fang Wu from Kaohsiung Medical University in Taiwan had six people in their 20s eat hot soup for breakfast out of melamine bowls and another six eat soup from ceramic bowls. Then the researchers monitored participants’ urine for the next 12 hours. Three weeks later, the two groups were reversed.
For the rest of the day, the total melamine excreted in study volunteers’ urine was 8.35 micrograms following a melamine-bowl breakfast, compared with 1.31 micrograms after breakfast from a melamine-free bowl.
The researchers did not measure any health effects possibly related to melamine — and it’s not clear if those urine levels would lead to any long-term medical problems or if participants’ bodies were storing any of the chemical.
Still, Dr Wu and colleagues write in the Journal of the American Medical Association Internal Medicine: "Although the clinical significance of ... levels of urinary melamine concentration has not yet been established, the consequences of long-term melamine exposure should still be of concern."
Dr Langman says research into the chemical’s long-term biological effects should continue.
"The babies who were poisoned because of their being young had very low kidney function to begin with," he says. Their kidneys were therefore particularly vulnerable to the chemical.
What’s more, "clearly, poisoning acutely with this massive overload is different than long-term exposure", he says.
According to the US Food and Drug Administration, melamine is approved in the US for use in the manufacturing of some cooking utensils, tableware, plastics and industrial coatings, among other things. The chemical is likely to be more common in other countries, including China.
"American exposure from tableware must be astonishingly small, or not at all. (However), because of the Chinese poisoning epidemic, we have to be entirely vigilant all the time about our food supply," Dr Langman says.
Anyone who has a choice might as well avoid buying tableware made with melamine, because it does interact with some acidic foods and in the microwave.
"If you can avoid it, why use it?" he says.