Lithium is an essential substance for brain cognitive function, and a decrease in its levels can lead to aging and Alzheimer's disease, according to research findings. Additionally, it has been confirmed through animal experiments that supplementing lithium in the brain, like charging a lithium battery, can restore cognitive function.
The research team led by Professor Bruce Yankner of Harvard Medical School said on 6th that they discovered lithium plays a crucial role in maintaining cognitive function in the brain after analyzing human brain tissue and blood samples for 10 years.
Alzheimer's disease is a condition that impairs cognitive abilities such as memory and learning by damaging cells due to the accumulation of abnormal proteins inside and outside neurons. Clusters of amyloid beta protein (plaque) outside the brain cells are cited as a primary cause. Professor Yankner was the first to prove the toxicity of amyloid beta plaques in the 1990s.
Amyloid beta originally protects neurons, but when it escapes outside the brain cells and aggregates, it destroys neurons instead. Recently, a drug was developed that removes amyloid plaque to somewhat delay the symptoms of Alzheimer's disease, but it has limitations, as it can cause severe side effects such as brain swelling or hemorrhage.
Professor Yankner has uncovered that lithium naturally exists in the brain and is essential for cognitive function. An analysis of brain tissue from individuals who had different cognitive functions during their lifetime revealed that the concentration of lithium in the brain correlates with cognitive ability. In particular, brain tissue from patients with mild cognitive impairment or Alzheimer's disease showed very low levels of lithium.
The research team demonstrated through experiments on mice that lithium deficiency does not lead to symptoms of Alzheimer's disease but rather is a cause that progresses the disease. Mice that were fed food lacking lithium showed a lithium concentration in the brain similar to that of Alzheimer's patients.
Mice with low levels of lithium in their brains exhibited cognitive dysfunction symptoms similar to those of Alzheimer's disease. The research team also found that lithium in the mice's brains binds with amyloid plaques, impairing its function and leading to decreased cognitive abilities.
Additionally, the research team discovered that replenishing lithium in the brain leads to recovery of cognitive function. In experiments where various lithium compounds were administered to Alzheimer's disease mice, lithium orotate, a compound formed by the combination of lithium and orotic acid, was found to be the most effective in restoring cognitive function.
Lithium orotate not only prevented the progression of Alzheimer's disease but also helped in its prevention. This is because lithium orotate does not bind with amyloid plaques, thus not causing lithium deficiency in the brain. The research team also confirmed that administering only about one-thousandth of the existing lithium used in medications could enhance lithium function in the brain.
Professor Yankner noted, "While clinical trials on humans are necessary, measuring the lithium levels in the brain can be seen as beneficial for the early diagnosis of Alzheimer's disease," and added, "Using the results of this study, it could be possible to develop treatments for Alzheimer's disease that are much more fundamental than existing therapies." Some lithium compounds are already used as medications for treating depression or bipolar disorder.
References
Nature (2025), DOI: https://doi.org/10.1038/s41586-025-09335-x