Lithium is known to extend life in nematode worms, though I haven't seen much further exploration of the mechanism. Here, Japanese researchers show that lithium intake is also associated with human mortality - though as for all such large statistical studies, one would want to see confirming work from other parts of the world before taking it as fact: "Lithium is a nutritionally essential trace element predominantly contained in vegetables, plant-derived foods, and drinking water. Environmental lithium exposure and concurrent nutritional intake vary considerably in different regions. We here have analyzed the possibility that low-dose lithium exposure may affect mortality in both metazoans and mammals. ... Based on a large Japanese observational cohort, we have used weighted regression analysis to identify putative effects of tap water-derived lithium uptake on overall mortality. Independently, we have exposed Caenorhabditis elegans, a small roundworm commonly used for anti-aging studies, to comparable concentrations of lithium, and have quantified mortality during this intervention. ... In humans, we find here an inverse correlation between drinking water lithium concentrations and all-cause mortality in 18 neighboring Japanese municipalities with a total of 1,206,174 individuals ... Consistently, we find that exposure to a comparably low concentration of lithium chloride extends life span of C. elegans ... Taken together, these findings indicate that long-term low-dose exposure to lithium may exert anti-aging capabilities and unambiguously decreases mortality in evolutionary distinct species."