The Metals in the Brain That Might Drive Alzheimer’s Disease

Scientists have long speculated whether a build-up of metals in the brain might trigger Alzheimer’s, a school of thought that dates back to a study performed in the 1960s that found rabbits exposed to aluminum experienced brain damage. In fact, that same study has supported concerns that metals found in pots and pans and even deodorant might lead to a build-up of metal in the brain. And although there is no strong evidence to support those theories, scientists have discovered that a specific type of iron is associated with the formation of beta-amyloid plaques in the brain—a hallmark of Alzheimer’s disease.

Researchers from the University of Warwick in the U.K. have found an association between the presence of several forms of iron and the beta-amyloid plaques that characterize Alzheimer’s. They also found a magnetic iron oxide called magnetite which is not typically found in the brain within the plaques.

Iron is a naturally present metal in our body, along with other metals like zinc and copper. Metals are necessary elements that our bodies require to carry out the process of living. We also consume metals through things like food, which our body can typically clear through the kidneys.

But large amounts of metal cannot be cleared, and scientists have theorized that those metals can be deposited in the brain. The finding of the scientists from the University of Warwick gives us clues as to how a brain with Alzheimer’s disease begins to produce those metals, which could lead researchers to information about how and why Alzheimer’s first forms.

“Iron is an essential element in the brain, so it is critical to understand how its management is affected in Alzheimer’s disease,” said Joanna Collingwood, associate professor at the University of Warwick’s School of Engineering. “The advanced X-ray techniques that we used in this study have delivered a step-change in the level of information that we can obtain about iron chemistry in the amyloid plaques. We are excited to have these new insights into how amyloid plaque formation influences iron chemistry in the human brain, as our findings coincide with efforts by others to treat Alzheimer’s disease with iron-modifying drugs.”

It’s important to note that this study doesn’t prove that metals in the brain cause Alzheimer’s—just that there is an association between the presence of one type of metal and the plaques. Another limitation of the study is that it was conducted using only two people’s brain samples, and both had Alzheimer’s disease. To confirm the findings with more certainty, more people and a valid control would need to be analyzed. Still, it’s a finding worth exploring, because it shows that the formation of beta-amyloid could trigger an imbalance in metals—which might actually be what scientists developing drugs for Alzheimer’s need to target.

“These new findings raise challenging questions about the relative impacts of beta-amyloid aggregation, plaque formation, and disrupted metal homeostasis on the oxidative burden observed in Alzheimer’s disease,” wrote the study authors.

This study was published in the journal Nanoscale.