Lithium. Who knew?

From Reuters:

   Long-term consumption of tiny amounts of lithium may reduce the risk of Alzheimer’s disease and other forms of dementia, but only if the dose isn’t too small, according to a study that looked at levels of the element in drinking water throughout Denmark.

In fact, the wrong amount may actually increase dementia risk, researchers report in JAMA Psychiatry.

Lithium, used for years in drugs to treat depression and bipolar disorder, is a naturally-occurring element in drinking water in Denmark but levels vary by location. The team compared the estimated amount found in the water supplies of 275 municipalities to the rates of dementia, including Alzheimer’s, in those areas.