There are more than 1,000 chemicals known to be toxic to the brains of animals in lab experiments. Yet we only know of 214 for humans, and just 12 for developing fetuses and infants, a recent study revealed.
Why are these numbers so far apart? Is it because lab animals’ brains are more feeble and susceptible to chemicals than ours?
No. It’s because we can conduct experiments by feeding mercury, lead, and arsenic to rats to find out what happens to their brains. It’s unethical to do so in humans.
Unfortunately, that’s exactly what we’re doing – just not in a lab.
Without the capability to conduct a lab experiment on humans, we’ve got a few ways to find out exactly which chemicals are bad for our brains.
Typically, most of us are exposed to low levels of a wide variety of the chemicals in our lives – from paint, carpet, food, food containers, air, water, and more. If, after 60 years, you get sick, it’s hard to say what caused it.
Sometimes the harm can be much more subtle, like the loss of a few IQ points in a child who was exposed to a chemical before birth.
The exception is usually when a group of people is exposed day after day to high doses of a chemical on the job. When they all become acutely ill, it’s obvious there’s a problem. The cause is fairly easy to track down.
This method works for adults – resulting in the discovery of 214 neurotoxicants in humans – but not in developing fetuses and infants.
To find the dozen chemicals that harm the youngest brains, scientists compare exposure levels among a group of babies while still in the womb and then track their growth in their early years. Only by comparing them to one another, scientists can detect which chemicals cause problems.