Lithium present in tap water may protect against dementia

A recent publication published in JAMA Psychiatry suggests that the lithium present naturally in small quantities in tap water may have a protective effect against dementia. The study, coming out of Denmark, looked at 800,000 people and showed that people living in areas with high levels of lithium (>15 mg/L) showed a 17% reduction in risk of developing dementia. The results, however, are not clear cut, as the results also showed that moderate levels of lithium (between 5.1 and 10 mg/L) actually have an increased risk over people living in areas with lower levels (<5 mg/L), suggesting there is a sweet spot concentration for the effect.

As a drug, at much higher levels, lithium is already used as part of treatments for psychiatric disorders, like severe depression or bipolar disorder. It’s a very simple drug in that it is nothing more than a metal ion (like sodium in sodium chloride, aka common salt) and not a complex molecule as most drugs are. Patients on lithium may have their levels monitored to ensure the concentration in their blood falls within the range where it works best to reduce their symptoms (the so-called therapeutic range).

An interesting fact about lithium is that it was an ingredient (as lithium citrate) in the early formulations of the soft drink 7-Up until the late 1940s. You can find more about lithium as a drug and the blood test used to measure it here on LTO-UK.