Water may have an effect on your longevity. (Photo by anthony_goto)
Lithium is an essential trace element found mostly in drinking water and vegetables. However, nutritional intake of lithium varies considerably, depending on where you live.
In rats, a deficiency of lithium causes health problems such as behavioral abnormalities, but in humans, lithium deficiency is an unknown concept. On the other hand, there have been studies suggesting that lithium intake, even at low doses, is inversely correlated with suicide risk. High-dose lithium has been used for decades to treat psychiatric conditions such as bipolar disorder.
Lithium may also have other life-extending properties besides reducing suicide risk. For example, roundworms have been shown to live up to 36% longer when given lithium chloride, but the amounts used are 1000-fold higher than would be obtainable through diet. Such a high dose may not be necessary, however. In a recent paper roundworms were shown to live longer when given a low concentration of lithium chloride throughout their life – with the effect being less pronounced than with high doses (link).
The authors also looked at lithium in drinking water and total mortality in 18 neighboring Japanese municipalities. They found that tap water levels of lithium were inversely associated with overall mortality adjusted for age and gender. Since lithium levels have been associated with lower suicide rates, the authors also adjusted for suicide. The inverse association between lithium and overall mortality remained.
Lithium concentrations in drinking water ranged from 0.7 to 59 mcg/L. The highest value equals a concentration of 8.5 micromoles. A lithium concentration of 10 micromoles was enough to extend the lifespan of roundworms, while a concetration of 1 micromole was not.
The inverse association between mortality and lithium in drinking water obviously does not prove that lithium reduces mortality in humans, but the roundworm experiments show that the idea is not so far-fetched. Although the mechanism is still unknown, I wonder if the mental health aspect has something to do with it.
Too bad there doesn't appear to be any lithium in the tap water where I live, or at least they don't report it. It is also available as a supplement, but some countries may have customs restrictions on some or all forms lithium.
For more information on longevity, see these posts:
High HDL Cholesterol Reduces Risk of Dying in Men
Selegiline and Lifespan Extension
Does Intermittent Fasting Increase Lifespan?
The 7 Types of Aging Damage That End up Killing You