In Alzheimer’s disease, the nerve cells in the cerebral cortex die. An increased concentration of aluminum has been discovered in the brains of Alzheimer’s sufferers. Health risks from the light metal are manageable. Nevertheless, caution is advised in the kitchen.
For a long time, most scientists classified the light metal aluminum as harmless.
It was considered a serious criminal in the 1970s and 1980s. It was believed that it could be involved in the development of Alzheimer’s disease. That means it could have about 200,000 Germans on its conscience – every year.
After numerous investigations could not prove the guilt of aluminum, it was acquitted for the first time in the 1990s. It could continue to be used for the treatment of drinking water, in the household and of course in traffic engineering.
But now the case could be opened all over again. Italian scientists from the Catholic University in Rome have found a new connection between Alzheimer and discovered aluminum. The working group around Pasquale de Sole has pre-buttoned a protein in the human body that primarily stores iron, but can also be linked to other metals.
The results can now be read in the current issue of the specialist magazine “Clinical Biochemistry” – and could once again steer Alzheimer’s research in a completely new direction.
- The iron store is full of aluminum
The Roman scientists discovered something astonishing: The so-called ferritin in Alzheimer’s patients carries seven times as much aluminum as in healthy people. This observation fits all too well with the assumptions that were actually already shelved: If the death of nerve cells in Alzheimer’s disease were caused by aluminum, then it would be only logical that Alzheimer’s patients are more burdened by the light metal than it is the case in healthy comparators.
Therefore, the results are of great scientific interest, even if the aluminum should be acquitted again in the end. “You have to take the new findings seriously, even if no definitive statement about the dangers of aluminum can be made at the moment.”
The fact that the scientists from Italy have now selected ferritin to support the aluminum hypothesis is interesting in itself. Because actually the protein complex is known from a different context. Anyone who struggles with anemia from time to time has probably already read the word “ferritin” on their laboratory slip: It is the body’s iron store.
- Where iron binds, other metals also bind
In times when too little iron is taken in with food or too much has been lost, for example due to severe blood loss, iron is released again here. Without the trace element, however, nothing works in the body: It is mainly needed for the formation of new blood cells and for the development of muscles. With a well-filled iron store, this should always be possible, even if the circumstances are adverse.
But what if the ferritin still has tasks that go far beyond the storage of iron? Because the protein complex can bind not only iron, but also other metals, such as aluminum. Scientists Sole concludes from the results that ferritin not only stores iron, but also regulates the concentration level of other metals – by simply binding them to itself.
Because as vital as trace elements are, they can also be harmful. If the body is overloaded with iron, copper or aluminum, this has serious health consequences. The excess of metal ions destroys vital organs. The brain too.
To do this, of course, the aluminum has to get there first. And here too ferritin plays a role. The molecule can cross the blood-brain barrier and thus transport iron – but also aluminum – directly into the brain. How much aluminum gets into the brain with each individual ferritin molecule would then suddenly be very decisive.
- Overcharging with metal ions causes cells to die
Because the amount of aluminum supplied could directly determine the extent of the protein deposits, which are typical for Alzheimer’s patients, and thus the destruction of nerve cells. This harmful mechanism is already known from overloading with other metal ions. “It is known that the more iron a nerve cell contains, the more protein it deposits. It is conceivable that aluminum has a similar effect, ”says Beyreuther.
If that were the case, it would explain the drastic cell death in Alzheimer’s patients from the Italian study. Their ferritin molecules carried almost twice as much aluminum around with them as iron – an average of 62 percent. It should actually be the other way around. In the ferritin molecule of the healthy control group, iron dominated. The researchers found an iron content of up to 75 percent.
The question arises as to how the additional aluminum gets to ferritin – or in our body at all. Nowadays, at least externally, we are almost overloaded with aluminum. We drive carefree through the city on fancy super-light bikes, smear deodorants and sunscreen with aluminum additives on the skin and prepare food in aluminum pots. After all: here we are very well aware that we are handling aluminum. But the addition of aluminum is not always so obvious.
- Aluminum in drinking water
Aluminum can also be found relatively well hidden in drinking water. Whether this increases the risk of Alzheimer’s has been heatedly debated in recent years. For example, a large long-term study from France, in which almost 2000 elderly people were observed over a period of 15 years, is noteworthy.
Virginie Rondeau from the Institut National de la Sante et de la Recherche Medicale in Bordeaux and her team found a connection between the consumption of aluminum and the risk of dementia. Study participants whose drinking water contained a lot of aluminum had a more than two-fold increased risk of developing dementia. Already 0.1 milligrams of aluminum per day were associated with a stronger cognitive decline.
Nevertheless, aluminum can still be used and consumed, whether consciously or unconsciously. Not out of negligence and certainly not out of unwillingness, but simply because the study results could not be clearly confirmed by follow-up studies. An increased risk of Alzheimer’s disease could not be demonstrated either in the case of geographically determined aluminum exposure or in the case of high occupational exposure.
The current statement of the Federal Institute for Risk Assessment (BfR) in Berlin, which dates from 2007, therefore comes to the conclusion that neither foils, pots or roll-ons pose a risk.
- No aluminum foil around sour or salty food
However, neither rhubarb compote nor pickled cucumbers should be stored in the pots and foil. Because sour and salty things destroy the thin layer of aluminum oxide that naturally forms on contact with oxygen. It prevents aluminum from being transferred from the pot to compote and cucumber. If this layer cracks, the light metal can migrate into the food. The BfR therefore recommends that, in spite of the controversial study results, aluminum dishes and foil should not come into contact with strongly acidic and highly salty foods for too long.
But are these few precautionary measures still sufficient according to the latest findings? “Probably yes,” says Roland Brandt, member of the Scientific Advisory Board of the Alzheimer Research Initiative in Düsseldorf and neurobiologist at the University of Osnabrück. Based on the data from Italy, a high consumption of aluminum in drinking water can be a risk factor for Alzheimer’s disease.
However, it is far behind other risk factors such as bad eating habits, excessive alcohol consumption, low mental activity and lack of exercise. In addition, it has not been clarified how aluminum and Alzheimer’s are connected at all. “The study is very interesting because it demonstrates an association between increased aluminum loading of a storage and transport protein and Alzheimer’s disease. But it cannot show whether both parameters are causally related, ”he says. More aluminum in the brain damaged by Alzheimer’s does not necessarily mean that this is also responsible for the death of the brain cells.
- Many causes – one disease?
Beyreuther sees it similarly. What is actually behind the new results could only be shown by further extensive studies. “Alzheimer’s can probably have different causes. If an overload with aluminum is one of them, then certain people at risk could perhaps be treated in the future before the disease breaks out in them. Certain drugs that are currently used for an overload with iron could possibly be just as effective here, ”says Beyreuther.
The new study from Italy could not only expose one culprit – probably many – in the Alzheimer’s disease. “Research methods have improved significantly in recent years. So it is possible that we can find a connection today that could not be proven with the old means. From this point of view, it is worth reopening the case from scratch, ”says Beyreuther. Researchers could find new ways to combat Alzheimer’s. However, before medical professionals can use such new weapons, some evidence has to be gathered. The “Alzheimer’s” case is far from over.
