A 2011 article published in the British Journal of Psychiatry, titled “Lithium in drinking water and suicide mortality“, conducted a study on this topic. The study was carried out by Dr. Nestor D. Kapusta and his team, examining 6,460 drinking water samples taken from 99 regions in Austria.
Where Does the 7.2% Rate Come From? (The Mathematics of the Graph)
The bottom right corner of the first graph in the visual contains the linear regression formula:
y=−7,1852x+0,8652
- Here, x represents the amount of lithium in water (mg/l),
- and y represents the standardized suicide mortality rate (SMR).
According to the formula, if the amount of lithium in water (x) increases by 0.01 mg/l, the y value representing the suicide rate;
−7,1852×0,01=−0,071852
meaning it decreases by approximately 0.072 points (7.2%).
How Does Natural Lithium Affect the Brain?
The amount of lithium found in natural spring waters is tens of thousands of times below a medicinal dose. However, long-term use of these microscopic doses creates a “ripple effect” on brain chemistry:
- Suppression of Impulsivity: Lithium modulates impulsive and sudden reactions. Given that suicidal acts largely stem from momentary impulsivity, lithium’s inhibitory effect constitutes the most critical mechanism.
- Neurotransmitter Balance: It increases serotonin (happiness) and GABA (calmness) activity, while balancing glutamate, which leads to overstimulation.
- Neuron Protection: It supports the release of BDNF (Brain-Derived Neurotrophic Factor), which provides cellular repair in the brain.
Lithium Levels in Global Water Brands
In normal packaged drinking waters, lithium levels are generally not declared due to legal labeling standards and are quite low. However, some natural mineral waters (mineral springs) worldwide contain significant amounts of lithium due to the geological layers from which they originate.
In terms of standardization, the lithium content of some prominent global brands is as follows:
- Vichy Célestins
- Origin: France
- Amount: Approximately 0.80−5.0 mg/l
- Feature: It is one of the soda brands with the highest natural lithium content in the world.
- San Pellegrino
- Origin: Italy
- Amount: Approximately 0.20 mg/l
- Feature: It has a balanced mineral composition derived from volcanic layers beneath the Italian Alps.
- Gerolsteiner
- Origin: Germany
- Amount: Approximately 0.13 mg/l
- Feature: In addition to its rich calcium and magnesium composition, it also contains natural lithium.
- Evian
- Origin: France
- Amount: Approximately 0.01 mg/l
- Feature: It is a standard natural spring water containing trace amounts of lithium at a micro level.
Scientific Context and Points to Consider
While this study is scientifically accepted in the literature, the following points should be considered when evaluating its results:
- Difference Between Correlation and Causality: This research is an ecological (geographical) based study. It examines the relationship between the average lithium level in a specific region and the suicide rates in that region. A strong association (correlation) between two data points does not definitively mean that lithium in water directly and solely prevents suicides (causality); many variables, such as socioeconomic factors, can influence the process.
- Other Studies in the Literature: Many similar studies conducted worldwide (e.g., Texas, Japan, Greece) support the idea that trace amounts of natural lithium in drinking water may have a suicide-reducing effect. However, a large-scale 22-year individual follow-up study conducted in Denmark, for instance, did not detect a significant protective effect of lithium at these levels. There is still no complete consensus on the matter in the scientific community.
- Lithium Toxicity and Dose Difference: Lithium is a heavy psychiatric drug that can cause severe organ poisoning (toxicity) in high doses. The therapeutic doses used in psychiatry are hundreds of times higher than the microscopic (trace) amounts mentioned in this study regarding natural spring waters. Therefore, such studies do not aim to implement a societal intervention by adding lithium to water, but rather to understand the long-term and microscopic effects of naturally occurring elements on human psychology.