Lithium Offers Hope for Protecting Aging Brains from Alzheimer’s

A New Discovery in Alzheimer’s Research: The Role of Lithium

For nearly a decade, researchers at Harvard Medical School have been working to uncover the mysteries of Alzheimer’s disease and brain aging. Their latest findings suggest that a simple metal—lithium—may hold the key to understanding and potentially treating this devastating condition.

Lithium is most commonly known as a mood stabilizer used to treat bipolar disorder and depression. It was approved by the U.S. Food and Drug Administration in 1970, but its use in medicine dates back over a century. Now, for the first time, scientists have discovered that lithium is naturally present in the body in small amounts and plays a crucial role in maintaining normal cell function, similar to other essential nutrients like vitamin C or iron.

In a groundbreaking study published in the journal Nature, researchers from Harvard and Rush universities found that reducing lithium levels in mice led to brain inflammation and signs of accelerated aging. In mice bred to develop Alzheimer’s-like symptoms, a low-lithium diet worsened the buildup of beta-amyloid plaques and tau tangles, which are hallmarks of the disease. These changes were linked to faster memory loss.

However, maintaining normal lithium levels in aging mice protected them from these harmful brain changes. If these findings are confirmed in human studies, they could pave the way for new treatments and diagnostic tools for Alzheimer’s, a condition affecting an estimated 6.7 million older adults in the United States.

A Unifying Theory of Alzheimer’s Disease

The research offers a potential unifying theory that helps explain many of the complex factors involved in Alzheimer’s. Dr. Bruce Yankner, a professor of genetics at Harvard Medical School and lead researcher on the study, suggests that lithium may be part of a common mechanism leading to brain degeneration that precedes dementia.

“This data is very intriguing,” Yankner said. “It will take more science to determine whether this is a common pathway or one of several pathways to Alzheimer’s.”

Dr. Ashley Bush, a neuroscientist not involved in the study, highlighted the significance of the findings in an editorial for Nature. He noted that the research presents compelling evidence that lithium has a physiological role in the brain and that aging might impair the regulation of lithium levels.

How Lithium Works in the Brain

The study revealed that beta-amyloid plaques—sticky deposits that accumulate in the brains of Alzheimer’s patients—bind to lithium, depleting it from nearby cells. This includes microglia, the brain’s waste management system responsible for clearing away beta-amyloid. When lithium levels drop, microglia become less effective at removing these harmful proteins.

Yankner and his team tested different forms of lithium and found that lithium orotate did not bind to beta-amyloid. When given to mice with Alzheimer’s-like symptoms, lithium orotate reduced plaques and tangles, and improved cognitive function. Mice treated with lithium were able to navigate mazes and recognize objects, while those given placebos showed no improvement.

Caution Is Needed

Despite these promising results, experts caution against self-medicating with lithium. In its natural form, lithium is a soft, silvery-white metal that combines easily with other elements. While it is found in food and water, prescription doses of lithium can cause toxicity, particularly to the kidneys and thyroid.

The doses used in the study were much lower than those prescribed for bipolar disorder, and no signs of damage were observed in mice. However, Yankner emphasized that mice are not humans, and further research is needed before any conclusions can be drawn about its effects on people.

Evidence Builds for Lithium’s Role in Aging

This study builds on earlier research suggesting a link between lithium and reduced risk of dementia. A large Danish study in 2017 found that higher lithium levels in drinking water were associated with a lower risk of dementia. Another UK study in 2022 found that people prescribed lithium had a significantly lower risk of developing Alzheimer’s.

Until now, lithium was primarily seen as a psychiatric drug. However, recent advances in technology have allowed scientists to measure the tiny amounts of lithium in the body, revealing its importance in brain health.

The Future of Alzheimer’s Research

Yankner and his team plan to continue their research, focusing on how lithium deficiency occurs and how it can be addressed. They also hope to conduct toxicity trials to determine safe human doses.

The National Institutes of Health funded the study, along with grants from private foundations. Yankner emphasized the critical role of this support in making the research possible.

As scientists continue to explore the role of lithium in brain aging, the findings offer new hope for understanding and combating Alzheimer’s disease. For now, the message remains clear: more research is needed, and caution should be exercised when considering any form of lithium supplementation.