For many years, scientists have searched for the first event that sets off Alzheimer’s disease, the most common type of dementia. They’ve also puzzled over why some people’s brains show clear signs of Alzheimer’s—like the build-up of harmful proteins—but these people still stay mentally sharp.
Now, researchers at Harvard Medical School think they might have found a surprising clue: a small drop in lithium levels in the brain.
Lithium is a natural mineral found in the body and is best known as a medicine used to treat mood problems like bipolar disorder. But this new research shows that lithium might also play a quiet but important role in protecting the brain.
The researchers found that the loss of lithium in the brain could happen very early in Alzheimer’s disease—possibly even before people start having memory problems.
This study took 10 years and included both animal experiments and tests on brain tissue and blood samples from people at different stages of brain health.
In humans, the researchers noticed that people with lower lithium levels in their brains were more likely to have early memory issues. In mice, a lack of lithium caused Alzheimer’s-like changes to show up faster and made memory worse.
One reason this happens may be because of a protein called amyloid beta. These sticky proteins, known to be involved in Alzheimer’s, seem to grab onto lithium and pull it away from the areas where it’s needed. When this happens, brain cells can no longer function properly.
To test a possible solution, the scientists created a new type of lithium called lithium orotate. This version was designed to avoid being trapped by amyloid plaques. When mice with Alzheimer’s-like symptoms drank water containing lithium orotate, their memory improved, and signs of brain damage went away.
Alzheimer’s disease affects about 400 million people around the world. It is marked by clumps of amyloid beta, twisted strands of another protein called tau, inflammation, and the loss of important brain proteins.
But these signs don’t fully explain why some people lose their memory while others do not. Past treatments that aimed to remove amyloid beta have not worked well. They may slow down memory loss but do not stop it. This new discovery suggests that lithium could be a missing piece of the puzzle. It seems to affect many parts of the disease all at once.
To study lithium in humans, the Harvard team worked with a research group in Chicago that stores donated brain tissue. They measured the levels of 30 different metals in the brains and blood of people who had healthy memory, mild memory loss, or Alzheimer’s. Lithium was the only metal that dropped sharply in people with memory problems.
In their animal tests, mice fed a diet low in lithium aged faster, had more brain inflammation, developed more amyloid plaques, and lost memory. But when given lithium orotate, the damage stopped.
Even older mice regained memory and brain function. This special form of lithium worked at extremely low doses—about 1,000 times lower than what’s used for treating mood disorders. That means it could be safer for older adults, who are most at risk.
Still, the researchers warn that these results come from mice and brain samples, not from full human trials. People should not take lithium on their own, as it can be harmful if taken in high doses without medical supervision. The next step will be testing this new form of lithium in human studies to see if it’s safe and truly helpful.
If these future trials succeed, doctors may one day use simple tests to check lithium levels in the brain and offer low-dose supplements to those at risk. This could delay or even prevent Alzheimer’s from developing.
This discovery gives a new way of thinking about Alzheimer’s. Instead of treating just one part of the disease, like the protein build-up, lithium might work in several ways to protect the brain. It may even explain why some people with signs of Alzheimer’s in their brain never get symptoms—they might have just enough lithium to protect their brain cells.
If lithium orotate proves to work in humans, it could offer a low-cost, widely available way to prevent or treat Alzheimer’s. But for now, it’s still an exciting idea waiting to be tested in real people.
If you care about Alzheimer’s disease, please read studies that bad lifestyle habits can cause Alzheimer’s disease, and strawberries can be good defence against Alzheimer’s.
For more information about brain health, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
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