A groundbreaking study has discovered that low levels of lithium might be an unseen factor contributing to Alzheimer’s disease. This finding brings the possibility of a straightforward, affordable treatment option that can safeguard the brain well before it sustains lasting damage.

The study, featured in the journal Nature, indicates that increasing lithium levels through regular supplements could potentially delay or even reverse memory deterioration.

It’s a finding that the scientists who led the study say could one day lead to a cheap treatment for the world’s most common form of dementia.

Alzheimer’s disease is responsible for approximately 60% of dementia cases and affects about a million individuals in the UK. It gradually impairs their memory, reasoning, and independence.

The disease is believed to be triggered by the accumulation of amyloid plaques—a sticky protein—between brain cells, which obstructs their communication. Additionally, tau proteins within cells—which are essential for cell structure and nutrient transport—become twisted and lead to cell death. Eventually, these alterations cause the brain to shrink.

Current drugs only slow decline and carry the risk of troubling side-effects such as nausea, dizziness and sleep problems.

Recently, new medication options, like lecanemab, a type of immunotherapy, have been recognized for their ability to remove some amyloid plaques.

Though these medications can slightly slow mental decline, they come with significant risks, such as brain swelling and bleeding. Furthermore, they are expensive, costing thousands of pounds annually, and require hospital administration every few weeks.

No therapy yet stops or reverses the disease.

In the new study, researchers from Harvard Medical School compared donated brain tissue from people who had died with Alzheimer’s with that from healthy volunteers: they discovered that lithium was strikingly depleted in the parts of the brain hit hardest by the disease.

Lithium is a naturally occurring mineral that’s found in tiny amounts in the brain, where it helps nerve cells communicate and protects them from damage. The scientists believe the drop in lithium is the result of amyloid plaques draining the mineral from the cells surrounding them.

Further experiments in mice showed the same pattern: when lithium levels dropped, the animals developed more amyloid and tau tangles. As this happened, memory also worsened.

When the researchers gave the mice with Alzheimer’s lithium orotate, a form of lithium that can reach the brain easily and doesn’t become trapped by amyloid plaques, it restored the lithium levels in their brain tissue.

It also reduced the build-up of sticky protein plaques and tau tangles, and reversed their memory problems. (The lithium was adminstered in drinking water.) Professor Bruce Yankner, a neuroscientist who led the study, said: ‘This is groundbreaking. For the first time, we can see how lithium deficiency may drive the disease – and that correcting it might undo the damage.’

The research team says the next step is to see if the same results can be achieved in people.

Early safety trials of lithium supplements could begin within two to three years, involving small groups with mild memory loss. If it proves safe, larger studies will test whether it can slow, or even prevent, Alzheimer’s.

Because lithium – perhaps best known as a treatment for bipolar disorder – is a natural substance, it can’t be patented in its basic form, so drug companies have little incentive to fund costly trials. Researchers say progress will rely on public or charity funding, unless a company develops its own new version – for example, a branded tablet or slow-release formula it can licence.

For treating bipolar disorder, doctors prescribe lithium carbonate – a cheap but tightly monitored drug that can cause side-effects if the dose is too high.

The amounts being studied for Alzheimer’s are far smaller and thought to be safer, but human trials will need to confirm that. (While small amounts of lithium are also found in drinking water and foods such as grains and vegetables, the levels in these are far too low to have a medical effect.)

Commenting on the new study, Dr Leah Mursaleen, head of clinical research at Alzheimer’s Research UK, said the findings were ‘exciting’.

‘There are different types of lithium salts already used to treat conditions such as bipolar disorder and schizophrenia,’ she told Good Health. ‘Future research will need to explore which might be best suited for testing in dementia clinical trials. We’re still a long way from knowing whether this could work in people.’

Dr Richard Oakley, associate director of research and innovation at Alzheimer’s Society, said: ‘We don’t yet fully understand the way lithium works and more research is needed, at a much larger scale, before it can be considered a safe and effective treatment.’ He added: ‘Individuals should not self-prescribe lithium as this can be dangerous.’