Melamine, a chemical that sickened and killed babies in China when it tainted baby formula, can also leach off tableware and into food, according to a Taiwan study.
But researchers, whose results appeared in JAMA Internal Medicine, warned that their findings don't prove that melamine is harmful to people 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.
"Melamine tableware may release large amounts of melamine when used to serve high-temperature foods," wrote lead researcher Chia-Fang Wu from Kaohsiung Medical University in Taiwan.
How the study was done
For the study, six people in their 20s ate hot soup for breakfast out of melamine bowls, while another six ate soup from ceramic bowls. Then, the researchers monitored participants' urine for the next twelve 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 to 1.31 micrograms after breakfast from a ceramic bowl.
The study didn't 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.
Craig Langman, who studies kidney diseases at Northwestern University's Feinberg School of Medicine in Chicago, said that while the study raises interesting questions and concerns, it didn't prove anything.
But he also said that 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 said. "Clearly, poisoning acutely with this massive overload is different than long-term exposure.
'If you can avoid it, why use it?'
Melamine is approved in the United States for use in the manufacturing of some cooking utensils, tableware, plastics and industrial coatings, among other things. It is likely more common in other countries, including China.
"American exposure from tableware must be astonishingly small, or not at all," Langman added. "(But) because of the Chinese poisoning epidemic, we have to entirely vigilant all the time about our food supply."
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 said.
(Reuters Health, January 2013)