Sunday, June 29, 2008

Another reason to avoid eating grasshoppers: lead poisoning

Photo of grasshopper from suneko's flickr collection
If there weren't already enough reasons to avoid eating grasshoppers and other insects, a story on the San Francisco Chronicle presents another: lead poisoning. California residents from the Mexican state of Oaxaca have been found to have high levels of lead in their blood, and one of the likely exposure pathways is consumption of grasshoppers (known as chapulines in Mexico) from the Zimatlan area of Oaxaca. Lead is a potent neurotoxin, especially for the young. Exposure during youth may affect a person's adulthood -- recent research from the University of Cinicinnati shows a possible connection between lead exposure and the tendency to commit violent crimes (more from Living on Earth).

Here's part of the of the story from the Chronicle (my emphasis):

But health investigators on both sides of the border have concerns about traditional foods sent from Oaxaca's Zimatlan area after finding a possible link to high blood lead levels found in Oaxacans living in the scenic town of Seaside overlooking Monterey Bay.

"We are seeing an alarming rate of acute exposure," said Eric Sanford, a community health clinic doctor at the Seaside Family Health Center.

Sanford says many of his patients are U.S.-born children of Oaxacan parents from the Zimatlan area, who have higher blood lead levels than any other group in Monterey County with some reaching 20 micrograms per deciliter.

"I fear that other Oaxacans from the same villages living elsewhere in the U.S. may be experiencing the same problem," said Margaret Handley, an epidemiologist at UC San Francisco.

Researchers first linked the high lead levels to deep-fried grasshoppers, known as chapulines. Further tests showed similar results in pumpkin seeds, dried herbs, hot sauce and mole sent from Zimatlan. Handley's research showed that one grasshopper exceeded the Food and Drug Administration recommended daily limit of 6 micrograms of lead for a child by 60 times.

In Oaxaca, grasshoppers are fried and seasoned with garlic, salt, chili powder and lime juice in lead-glazed pots. Chemical reactions allow the bugs to absorb lead during cooking and storage, according to Mario Villalobos, a chemist at the National Autonomous University of Mexico, who works with Handley.

But Villalobos has no answer when asked why U.S. residents from Zimatlan have higher lead blood levels than immigrants from other parts of Oaxaca, who eat the same foods.

"We have yet to pinpoint why this problem is so localized," said Villalobos. "It'll take more extensive research and more tests to solve this mystery."



More articles about eating insects: my post about why some humans are queasy about bug eating (including me), the new wave of entomophagy (eating insects) in the New York Times Magazine (including a restaurant in Santa Monica, California) and "Eating bugs — tasty and good for the environment?" from Earth News.



Random link from the archive: Indian Dal Export Ban

Technorati tags: Mexico : Food

4 comments:

Anonymous said...

The first thing that comes to mind is the lead in their pottery. I vaguely recall hearing warnings about certain Mexican pottery and its lead content. If anything is stored there for any period of time, it's probably going to transfer its lead the food within.

Anonymous said...

This isn't a reason to not eat grasshoppers. It's a reason to not use Mexican cooking utensils.

Jason said...

Did you even read the entire article?

Marc said...

Admittedly, the headline is a little imprecise -- perhaps it should have also referred to the region in Mexico and perhaps the type of cooking vessel being used -- and my summary was a little bit incomplete, but it's a fact that a key part of the article was that grasshoppers were a vector for lead exposure. Recall that the article says "Handley's research showed that one grasshopper exceeded the Food and Drug Administration recommended daily limit of 6 micrograms of lead for a child by 60 times" -- so someone eating grasshoppers cooked in that region might ingest a serious dose of lead.

The article also implies that grasshoppers are more likely than other foods to pick up lead: "Chemical reactions allow the bugs to absorb lead during cooking and storage." And note that even though the article says that high lead concentrations were found in other foods, state officials issued notices warning against eating grasshoppers, not notices telling people not to use lead glazed pots or not to eat other foods that had been found to absorb lead. So there seems to be something special about grasshoppers -- perhaps they are a lead hazard even in pots which have relatively low levels of the heavy metal in the glaze.

The end of the article makes it clear that the situation appears to be too complex to pin on either grasshoppers or cookware -- "[Mexican chemist] Villalobos has no answer when asked why U.S. residents from Zimatlan have higher lead blood levels than immigrants from other parts of Oaxaca, who eat the same foods." -- which is why one of the lead authors finds that says "It'll take more extensive research and more tests to solve this mystery."