December 11, 2017
Drinking water that contains tiny amounts of lithium, a metal found naturally in mineral springs and igneous rocks, may help slow death rates in patients with Alzheimer’s disease, according to a new study. The presence of lithium in tap water was also correlated with a lower incidence of obesity and diabetes, which are linked to a much higher risk of dementia.
Scientists at Brock University compared the lithium levels in tap water across 234 counties in Texas. They found that areas with more lithium had lower rates of Alzheimer’s mortality, along with lower rates of obesity and diabetes.
“We found counties that had above the median level of lithium in tap water (40 micrograms per liter) experienced less increases in Alzheimer’s disease mortality over time, whereas counties below that median level had even higher increases in Alzheimer’s deaths over time,” said study author Val Fajardo.
So, is it time to start supplementing drinking water with lithium? Not quite. It is, after all, considered a mind-altering drug used to control the symptoms of bipolar disorder.
“There’s so much more research we have to do before policy-makers look at the evidence and say, OK, let’s start supplementing tap water with lithium just like we do in some municipalities with fluoride to prevent tooth decay,” said Fajardo.
While the correlation supports a Denmark study from earlier this year that found Alzheimer’s risk lowered in areas with high levels of lithium in drinking water, it only shows a link between the lithium levels and health benefits—not a direct cause. There could be other factors at play that are actually causing the mortality of dementia patients to slow down.
“Certainly, other factors could potentially confound the relationship that we observed with trace levels of lithium in the drinking water and Alzheimer’s disease mortality,” said Fajardo, though the study authors tried to minimize that by controlling for gender, race, education, air pollution, rural living, physical inactivity and the prevalence of obesity and diabetes.
While lithium is certainly an element that has shown promise in the lab and in studies like this one, the Denmark study showed that only relatively high levels of lithium lowered the dementia risk—moderate levels actually increased risk by 22 percent.
Other studies have suggested that lithium, when taken at very high levels for bipolar disorder, increases gray matter in the brain. In 1990, a study that looked at 27 counties in Texas showed that lower levels of lithium in drinking water were associated with higher levels of suicide, homicide and rape. The group with the highest amount of lithium had almost 40 percent fewer suicides than the group with the lowest amount.
Scientists still aren’t sure exactly how lithium works in the brain, though, and more studies will be needed before a strong link between lithium levels and dementia prevention can be established.
“Moving forward, studies should move toward larger and more controlled study designs to assess the causal effect of trace lithium on cognitive function in humans,” said Fajardo.