Lead poisoning vanquished fearsome Samurais

Consequently, they were unable to cope with political crises, which led to their eventual downfall, said Tamiji Nakashima of the University of Occupational and Environmental Health, who analysed the bones of Samurai children and adults to discover their cause of death.

Based on chemical and X-ray analysis, the bones of the children contained levels of lead dozens of times higher than both the male and female adults, the German magazine Der Spiegel reported.

"The median value for the children three years of age and under was over 50 times higher than that of their mothers," the study said, according to the Daily Mail.

Lead, which is particularly harmful to children damages the nervous and reproductive systems, causes high blood pressure and anaemia, and accumulates in the bones.

White facial powder used by the women was the cause.

"The white face powders used in those days were made from mercury chloride and white lead. Lead levels in the bones of adult women were roughly double those of men in the study. And their breast milk was likely highly-contaminated, leading to the very severe lead levels in the youngest children," the study report said.

"The high lead concentrations in the Samurai children of the Edo period may have left them intellectually incapable of dealing with the final political crisis between 1853-1867, resulting in the downfall of the Shogunate," said Nakashima.

"A ruling class afflicted with brain damage isn't a recipe for success. As Samurai were the ruling class, severe political insecurity could develop when highly lead-contaminated samurai children grew up," added Nakashima.