Medieval Europeans with more money suffered from more metal
In Medieval Europe, there was a price to be paid for beautiful furnishings that went beyond the price of the products themselves. Materials that made certain items more precious could also make them more dangerous, such as lead used in glazes on food containers. In small, gradual doses, the toxic effects of these ingredients were slow to be felt, making diagnosing the resulting health effects nearly impossible to doctors and alchemists at the time. Modern testing of remains from around Europe have found plenty of evidence that the owners of the finer things in live were also victims of them.
A survey of bodies from six different cemeteries in Northern Europe found lead in much higher concentrations in wealthy families. Day to day life in a nicely furnished household would have included contact with lead from coins, rainwater collected off of leaded roof tiles, and the glazed crockery these families ate off of. Plates and vessels were often glazed with lead oxide, which added an attractive luster to plates while making them easier to clean. The catch, of course, was that food stored in these containers, especially hot or acidic foods, would cause the glaze to break down, letting the lead leach into the food. Measurable build-up was found at much higher rates in urban cemeteries than poorer, rural locations, pointing to these key elements of upper-class lifestyles being to blame.
Metal poisoning wasn’t a complete mystery, although it wasn’t very well understood. Lead was known to cause mental illness and death since ancient Rome, but that was usually associated with miners or people who ingested acute doses of the metal, such as with deliberate poisonings. Owners of fine crockery probably didn’t understand how these products could pose a risk over longer lengths of time, which isn’t surprising considering the crude state of medicine and chemistry in 1100 AD.
If a person did go to a doctor, the prescribed cures of the day may not have been very safe. While checking for lead build-up, the researchers from the University of Southern Denmark also found some bodies with unusual concentrations of mercury as well. This toxic metal also had multiple uses in Medieval Europe, including treatments for leprosy and syphilis. Again, there was an urban bias seen in such treatments, with rural bodies having lower concentrations of Mercury than their urban counterparts. There were also differences in the mercury levels between different towns, which may have just been to the local treatment preferences of doctors in those areas.
Source: Being rich in the Middle Ages led to an unhealthy life by University of Southern Denmark, Phys.org