Get the lead in. ancient Egyptians added lead salts to their black eyeliner to prevent bacterial infections.
D. Vigears / C2RMF
Obviously, the ancient Egyptians did not get the memo about lead poisoning. Their eye makeup was full of the stuff. Although we now know that lead can cause brain damage and miscarriages, the Egyptians believed that cosmetics containing lead protected against eye diseases. Now new research suggests that they were on to something.
Previous work indicates that the Egyptians added lead to their cosmetics on purpose. When analytical chemist Philippe Walter and colleagues at the CNRS and the Louvre Museum in Paris analyzed the composition of several samples of the famous bold, black eyeliner Egyptians in the Louvre collection, they identified two types of lead salt not found in nature. This means that the ancient Egyptians had their synthesis. But making lead salt is a tricky process that requires delicate trend for weeks - and unlike other common makeup components, the salts are not glossy. So why do they bother?
The ancient manuscripts have given scientists a clue. It turns out that in the days, people did lead salts and used them as treatments for eye ailments, scars and discolorations. When Walter said chemist Christian Amatore of the Ecole Normale Supérieure in Paris on the findings, Amatore says he was intrigued because lead is now known to have many toxic effects.
To see if the initiative could confer health benefits, Amatore, Walter, and colleagues added lead salts to human skin cells called keratinocytes, which were grown in the laboratory. The researchers hypothesized that the driver stresses the cells and cause them to produce hydrogen peroxide, nitric oxide, and other compounds involved in the body's immune response. And indeed, cells treated with lead began the more nitric oxide pumping than control cells, reports the online team Analytical Chemistry .
Amatore says that nitric oxide triggers a series of biochemical processes in the body that ultimately sends immune cells called macrophages to the site of infection, where they engulf the invading organisms. That's probably not what is happening in keratinocytes, says immunologist Martin Olivier of McGill University in Montreal, Canada, who was not involved in the study. It is unlikely that macrophages and other immune cells would leave the body and burst through the skin to fight against infectious agents to the surface, he said. Instead, nitric oxide released by keratinocytes could directly kill eye-disease causing bacteria on the skin or near the eye by breaking the structure or DNA of a bacterium. Another plausible scenario, says Olivier, is that lead itself could stimulate immune cells already directly present in the eyelid.
This potential benefit of lead is contrary to everything we know about the substance, but could adapt the hormesis model, says epidemiologist Jennifer Weuve of Rush University Medical Center in Chicago, Illinois. "The premise behind hormesis is that, for some exhibitions, there might be a window where exposure is harmful, but also where it is useful," she says.
Yet Weuve sets cautions against adding lead to the eyeliner in your makeup bag modern people are living much longer than the ancient Egyptians. - many of whom died in their 30s - and the dangers of prolonged exposure to the lead outweigh any antimicrobial benefit, she said. in fact, the strategy of eyeliner Egyptians have turned against them if they had lived long enough, she notes, that long-term exposure to lead can increase the risk of developing cataracts.
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