The Doctor Weighs In

Poor Mattel; three huge recalls of lead-tainted toys, despite conscientious testing efforts. Those babe-in-the-woods quality control experts were no match to the wily new capitalists from China, determined to maximize profit. Isn’t that the name of the game?

What’s next? A toxic Barbie? That may actually be a blessing in disguise.

But, it’s not only toys. Here is an item from today’s San Jose Mercury:

SACRAMENTO - "The state's public health department asked parents Thursday to toss certain Chinese-made lunchboxes potentially containing dangerous levels of lead - the same ones it distributed in a campaign to promote healthy eating.                                                                                 

The department distributed more than 350,000 of the canvas lunchboxes, only to find out that at least three that were tested in a batch of 56,000 contained "significant" levels of lead."

The toxic legacy of lead

Lead was mined in Asia Minor as early as 8000 years ago. Because of its easy malleability it was used in making ornaments, like the 7^th millennium BC old necklace found in Anatolia. Even today, Richard Serra, one of our foremost sculptors, used lead in his early work, before switching to the less malleable, but also much less toxic iron. Lead as a poison was recognized in 250 BC by a Greek physician and poet (Nicander of Colophon) living in Anatolia. To the history buffs among you, here is a fascinating story. Wealthy Romans suffered more than their fair share from gout. Their riches enabled them to drink their wine, an expensive luxury in those days, from ceramic amphoras (wine vessels) and cups. To avoid leaching of the lead, the ceramic material needs to be fired at high temperatures. Alas, they did not possess the technology for that. To add insult to injury, the rich preferred decorated vessels over the plebeian looking plain vessels. But those decorations contained lead paint, and the glazing process to lock in the paint was done with inadequately hot fire. But wait, wait, there is more. The Romans imported their Port wine from Oporto, Portugal, and they liked it sweet. So those wily early Portuguese farmer capitalists added a sweet additive to the wine: lead acetate. Now we know where the belief that red wine can cause gout came from.

What makes it toxic?

Lead causes its harm by mimicking iron, calcium and zinc, biologically important metals. It interferes with the synthesis of hemoglobin, hence the anemia that it causes looks just like iron deficiency anemia. It also wreaks havoc with the GI system, causing nausea, vomiting, diarrhea, constipation.

But the most insidious action of this metal is in the nervous system. The symptoms range from irritability, lethargy and loss of appetite to cognitive abilities like loss of memory, irrational behavior, and in children-deficient development of the nervous system.

The reason for the devastating effect on nervous system is that interferes with the neurotransmitter glutamate (an amino acid). In fact, more than half the neurons in the brain are glutaminergic. One of the receptors for glutamate is called N-methyl-D-aspartate or NMDA, and lead binds avidly to this receptor, inhibiting its action. What do neurons with this receptor do? You guessed it: they are important in brain development of children, and they are crucial to the acquisition of knowledge and memory. Most of the neurons in the hippocampus, a sea horse-like structure in the brain, contain NMDA receptors; the hippocampus also happens to be the site of long term memory formation.

And the implication of lead exposure?

The obvious ones are its GI, hematological and neurological toxicities. But did anybody look at the role of lead exposure in the huge rise in ADHD diagnoses? Hyperactivity, short attention span, learning disorders are all consequences of lead toxicity. A study measuring blood lead levels in these kids is sorely needed.

And for you history buffs. Is it possible that one of the many reasons leading to the decline and fall of the Roman Empire was chronic lead exposure? Consider this: A few skeletons of Roman nobles were tested for lead content; it was extremely high, in the toxic range.

Is the American Empire next?

Dov Michaeli MD, Ph.D is in the biotech industry and was probably exposed to lead in his childhood.