Aluminium in the Human Brain

Any much is too much!

A few years ago I published a paper entitled ‘Aluminium in human brain tissue; how much is too much?’ and you can read the paper free of charge using the link. I thought we might explore this concept further herein and in particular identify threshold concentrations for aluminium in brain tissue below which there are no signs of neurodegenerative or neurodevelopmental disease.

I think it is important to stress at this point that the aluminium content of human brain tissue can only be measured post mortem. Unlike for example iron, the chemistry of aluminium does not lend itself to any form of non-invasive measurement or imaging. However, this limitation in the measurement of brain aluminium should not deter any attempt to lower brain aluminium content by therapeutic means. For example, regular drinking of a silicon-rich natural water will help to remove aluminium from brain tissue since lowering the aluminium concentration in blood will drive aluminium from the brain and across the blood-brain barrier.

Remember, the blood-brain barrier is not impermeable it is selectively permeable. In addition foreign substances for which there are no naturally selected transport pathways, such as aluminium, may pass out of the brain down concentration gradients by a process known as residual leakiness.

We have two sets of what I might describe as control brain tissues.

The first set are tissues from 20 individuals classified by the London Brain Bank as brain tissues taken from donors without any overt signs of neurodegenerative disease and importantly brain tissues without any clear neuropathology characteristic of neurodegenerative disease. A statistical summary of these tissues is shown below.

The full data set is available through our seminal publication.

As a ballpoint figure the data suggest that a brain aluminium concentration below 1.0 ppm dry wt. is not associated with any form of overt neurodegenerative disease.

The second set are tissues from 12 individuals classified by the Multiple Sclerosis Brain Bank as brain tissues taken from donors without a diagnosis of multiple sclerosis. A statistical summary of these tissues is shown below.

The full data set is available through our publication.

Similarly with the first data set the cut-off for no overt signs of disease, in this case multiple sclerosis, was 1.0 ppm dry wt..

This second data set was complicated by the fact that 8 out of 12 of the control brains came from donors who died of some form of cancer.

I decided to compare the two control data sets and I asked my esteemed colleague and statistician Dr Elizabeth Clarkson if the two sets of control brain tissue were significantly different from one another. They are not and this means that in the future should I wish to do so the data sets can be pooled to produce a single control group including brain tissues from 32 individuals.

Many of you, looking more closely at the raw data, may have noticed that brain tissue taken from individuals who died with some form of cancer was higher than the non-cancer subgroup. Indeed if the cancer subgroup consisting of 8 individuals is compared with the remaining non-cancer subgroup consisting of 24 individuals then we find that the brain aluminium concentration is significantly higher in the cancer sub-group.

One can only speculate as to the possible significance of higher brain aluminium in the cancer sub-group of the neurodegenerative disease free control group. Perhaps cancer brought their lives to an end before any overt symptoms of neurodegenerative disease were evident. Personally I prefer this conclusion as compared to a recent suggestion in an animal model that cancer protects against Alzheimer's disease.

We know that aluminium has no essential role to play in any living organism and we can safely surmise that its presence in human brain tissue is unwanted. We can even go further as I have done with respect to Alzheimer's disease and conclude that no aluminium in brain tissue means no neurodegenerative disease and no neurodevelopmental disease, the latter meaning no profound autism.