Study details and key findings

Lithium is a common metal, and it was first approved by FDA to treat mood disorders in 1970, though doctors had already been using it as a treatment many years before that. Lithium is commonly used as a mood stabilizer for people who have bipolar disorder or depression.

In the study, the researchers used an advanced type of mass spectroscopy to measure trace levels of 27 different metals in the brain tissue and blood samples of older adults who were cognitively healthy, had mild cognitive impairment, or had advanced Alzheimer's.

According to the researchers, lithium was the only metal that had markedly different levels across the three groups, with levels being the highest in those who were cognitively healthy and much lower in those with mild cognitive impairment or Alzheimer's.

The researchers also found that "the lithium that was left in the brain [of people with cognitive impairment or Alzheimer's] was trapped in these amyloid beta deposits, reducing its bioavailability." Beta-amyloid plaques can disrupt communication between nerve cells and are often considered a hallmark of Alzheimer's disease.

To explore the potential effects of lithium deficiency, the researchers conducted an experiment with mice that were engineered to have Alzheimer's. Mice that were given a lithium-deficient diet had increased beta-amyloid plaques, as well as impaired learning and memory. They also had impaired neuron and microglia function. Neurons are responsible for mediating electrical brain signals, and microglia help clear out waste in the brain, including beta-amyloid plaques.

Commentary

According to CNN, this study is the first time researchers have shown that lithium is naturally present in the body, even in tiny amounts, and that it is necessary for cells to function properly, particularly when it comes to maintaining brain health.

Other research has also suggested that lithium may have a protective effect on brain health. For example, a large Danish study from 2017 found that people with higher lithium levels in their drinking water were less likely to be diagnosed with dementia compared to people with lower levels in their water. Separately, a 2022 U.K. study found that people prescribed lithium were roughly half as likely to be diagnosed with Alzheimer's compared to a control group.

According to the researchers, the study's findings could lead to new diagnostic and treatment methods for Alzheimer's disease. For example, doctors could measure patients' lithium levels for potential signs of Alzheimer's years before symptoms start to appear. Lithium salts could also be used as a potential treatment for the disease, but the most suitable type of lithium and a non-toxic dose will need to be identified first.

However, Yankner emphasized that people should not take lithium compounds on their own to prevent or treat Alzheimer's since the study's findings currently only apply to mice, not humans.

"I do not recommend that people take lithium at this point, because it has not been validated as a treatment in humans," Yankner said. "We have to be cautious because things can change as you go from mice to humans."

However, he was optimistic about the study's findings and said he hopes lithium orotate or a similar compound can be tested in clinical trials soon. "My hope is that lithium will do something more fundamental than anti-amyloid or anti-tau therapies, not just lessening but reversing cognitive decline and improving patients' lives," Yankner said.