In 1965, researchers found that rabbits injected with aluminium developed toxic protein tangles in their brains. This led to speculation that aluminium from cans, cookware and even the water supply could be causing dementia. Importantly, these results were only seen with extremely high doses – far more than we normally get from our environment.
Aluminium in food and drink is in a form that is not easily absorbed into the body. Hence the amount taken up is less than 1% of the amount present in food and drink. Most of the aluminium taken into the body is cleaned out by the kidneys. Very small amounts of aluminium are seen in the normal, healthy brain. This is considered normal and doesn’t appear to be toxic.
Case studies have described individual people who have accidentally been exposed to extremely high levels of aluminium and gone on to develop memory and thinking problems. However as these people died many years after exposure, it is impossible to say whether the aluminium exposure was connected to the damage to their brains.
The studies that look at aluminium in the brains of people with Alzheimer’s disease have mixed results. Some researchers have found aluminium in the brain but failed to show whether it was at higher levels than in healthy individuals.
Other studies have suggested that high aluminium exposure might be related to an increased risk of dementia. These studies are small and others contradict them. The levels that are considered high are far greater than people are normally exposed to.
No convincing relationship between aluminium and the development of Alzheimer’s disease has been established.
