Lead is toxic mainly because it preferentially replaces other metals (zinc, calcium, and iron) in biochemical reactions. it actually interferes with the proteins in human bodies that "cause certain genes to turn on and off by displacing other metals in the molecules. This essentially changes the shape of the molecule so that it can't perform its function. Scientists are doing research to learn which molecules bind with lead but some of the proteins known to be affected by lead regulate blood pressure, heme production (which can lead to anemia), and sperm production. "Lead displaces calcium in the reactions that transmit electrical impulses in the brain, which is another way of saying it diminishes your ability to think or recall information."
As early as the 1600's, a self-proclaimed alchemist named Paracelsus pioneered the use of minerals in medical practices. He believed that all things have both good as well as poisonous facets. He believed that lead, in small doses, had curative effects.
As you know, many substances are non-toxic or even essential in small or trace amounts. Yet in larger doses, these same substances can be poisonous. A prime example is iron. It is needed transport oxygen in your red blood cells, yet too much oxygen can kill humans. Even oxygen which is necessary for life can be lethal if you get too much. But one substance that is never safe is lead. Sorry Paracelsus. There isn't safe minimum exposure because lead accumulates in the body. In the US and other places, I am certain, the government has regulations regarding acceptable limits for products and pollution because lead is useful and necessary, but the reality is, any amount lead is too much.
So now you know why lead is poisonous. The best way to keep your exposure to lead at a minimum is by reading product labels. Many companies no longer use lead but there are still products out there that contain lead.
Dharma Frog, my wise teacher, and friend will be here tomorrow for another insightful life lesson. I hope you'll plan on joining me then. Until we meet again, I wish you all a good day and