New Research on Iron and Dementia

There is a belief among some that ingestion of excessive iron may cause or contribute to AD.  This week's issue of ALZ Forum carried an article that supported this idea.  The article presented information from a study published in the journal Molecular Psychiatry that reviewed autopsy results for people who did and who did not have evidence of AD at death.  The review found a very strong correlation between people who displayed evidence of AD and the presence of iron in the temporal cortices.  The article stated, "Only people with clinical and pathological hallmarks of Alzheimer’s disease had more cortical iron."

The researchers did not come to a strong conclusion about the role of iron in AD pathology, although they suggested some possibilities.  One limitation of the study was that it could only examine the brains of people who had already died.  So their methodology couldn't correlate the progress of the disease with the amount of iron accumulating in the cortices.  However it was evident to the researchers that the concentration of iron rises late in the AD pathology.

But what role might iron have in AD pathology?  The ALZ Forum article stated that this question has been long debated, but there is no consensus.  A researcher from the "Religious Orders Study and Memory and Aging Project" discussed autopsies where the presence of amyloid plaques and tau tangles did and did not correlate well with dementia prior to death.  He said that elevated iron appeared in the brains of those who displayed dementia but not necessarily in the brains of those who did not.  This recalls from the Nun study the apparent anomaly of nuns who displayed normal cognition prior to death, but their autopsies found their brains displayed significant damage of the type consistent with AD.  (The Nun study and the Religious Orders study run cooperatively.)

The article pointed out that there is normally iron in the brain cells.  However, free iron outside the cells may be the problem.  The article discussed some studies that have tried to improve cognition by removing iron from the brain.  So far, these have not produced positive results.