Vitamin D could help clear toxic Alzheimer’s protein from the brain

Researchers at Tohoku University investigated whether vitamin D could help clear a toxic protein called amyloid, which builds in the brain of people with Alzheimer’s, damaging nerve cells. Using mice, they found that 24 hours after injecting an active form of vitamin D, clearance of the protein had increased.

Their results suggested that vitamin D was also rapidly cleared from the brain. Because of this, the researchers believe repeated injections would be needed – but they warn that this in itself could have adverse side effects.

Meanwhile, US researchers investigating the mechanisms that help remove amyloid from the brain in healthy people have shed new light on how these change in old age. It’s thought the failure of mechanisms that transport the protein across the blood brain barrier could be responsible for the build-up of amyloid in people with Alzheimer’s. The team theorises that the failure of this system is mitigated by a second process, which transports amyloid into spinal fluid.

The team believes there are potential failures in this second protective system that might therefore be linked to the build up of amyloid associated with Alzheimer’s. The clearance of amyloid from blood to cerebrospinal fluid barrier (blood-CSF) could be a new area of focus for researchers looking for answers to dementia.

Both papers are published in the journal Fluids and Barriers of the CNS.

Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, said:
“These two studies give us new insight into how we might stop amyloid from wreaking its havoc in the brain, but there is still much we need to know. Earlier studies have linked vitamin D deficiency to cognitive decline, but simply boosting intake might carry risks, so research still needs to find a safe and effective way forward. In order to know whether increasing our intake of vitamin D could protect against Alzheimer’s, we need to see clinical trials that test this theory comprehensively.

“Stopping amyloid build-up is a key target for scientists’ efforts to defeat dementia, but there are many unanswered questions in this area. We need to see far more research to fully understand the mechanisms involved, and that requires a substantial increase in investment for dementia research.”

Alzheimer’s Research UK