In 2003 a 58-year-old Caucasian male with no previous medical history of note was diagnosed with Alzheimer's disease. Ten years previous to this the man, from the north-east of England, began to work with the preparation of a novel material (DARMATT KM1) used as insulation in the nuclear fuel and space industries. This work exposed him to aluminum sulphate 'dust' on a daily basis over 8 years. An 'ordinary' dust mask was supplied to protect against inhalation of the materials. Within a short time of starting this work the man complained of headaches, tiredness and mouth ulcers. By 1999 he started to show problems in relation to memory and suffered depression. Following his death, aged 66, in 2011, a neuropathological examination confirmed advance stage Alzheimer's disease. There then followed the most comprehensive investigation ever of the aluminum content of the frontal lobe of a single individual with 49 different tissue samples being measured for aluminum. Professor Chris Exley, of The Birchall Centre, at Keele University, said: "The results showed unequivocally that the frontal lobe contained an average aluminum content which was at least four times higher than might be expected for an age-matched control brain. "The observation that air-borne aluminum dust was most likely responsible for the elevated levels of aluminum in the brain must then heavily implicate the nose and possibly the lungs as the main routes of entry of aluminum into the body and the brain. "Overall, these results suggest very strongly that occupational exposure to aluminum contributed significantly to the untimely death of this individual with Alzheimer's disease."
Aluminum
In 1965, researchers found that rabbits injected with an extremely high dose of aluminum developed toxic tau tangles in their brains. This led to speculation that aluminum from cans, cookware, processed foods and even the water supply could be causing dementia. The ability of this high dose aluminum to induce tau tangles, increase amyloid levels and contribute to the development of plaques has been shown in laboratory experiments on animals.
Importantly, these results were only seen with extremely high exposures that far exceed the levels that can enter the body through food or potentially through contact with aluminum cookware.
Since this study was reported, much research has been done on the relationship of aluminum and Alzheimer's disease. As yet no study or group of studies has been able to confirm that aluminum is involved in the development of Alzheimer's disease.
Aluminum is seen in the normal, healthy brain. It is not clear how aluminum is getting into the brain from the blood. The levels currently seen in peoples brains hasn't been shown to be toxic but an aging brain may be less able to process the aluminum. Although aluminum has been seen in amyloid plaques there is no solid evidence that aluminum is increased in the brains of people with Alzheimer's disease. No convincing relationship between amount of exposure or aluminum in the body and the development of Alzheimer's disease has been established.
Aluminum in food and drink is in a form that is not easily absorbed in to the body. Hence the amount taken up is less than 1% of the amount present in food and drink. Most of the aluminum
um taken into the body is cleaned out by the kidneys. Studies of people who were treated with contaminated dialysis have shown an increase in the amount of aluminum in the brain. This was believed to be as a result of inadequately monitored dialysis which then led to encephalopathy related dementia. Methods of dialysis have since been improved and doctors are better able to predict and prevent this form of dementia.
One large recent study did find a potential role for high dose aluminum in drinking water in progressing Alzheimer's disease for people who already have the disease.
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