Scientists have not yet conclusively discovered whether aluminum causes Alzheimer’s disease. Historical research suggests this metal may be a factor. However, some modern scholars disagree. Alzheimer’s disease is a brain disorder that causes memory loss and trouble thinking. It eventually affects a person’s ability to perform simple tasks. AD is the most common cause of dementia in the elderly.
Scientists don’t yet fully understand the causes of Alzheimer’s disease, although risk factors may include:
age-related changes in a person’s brain
a person’s genetic or family history
a person’s environment
This article presents the historical and current research on the link between aluminum and Alzheimer’s disease and indicates whether other heavy metals can cause Alzheimer’s disease.
Is there a link between aluminum and AD?
Scientists don’t know for sure if aluminum causes Alzheimer’s disease. To date, research on the link between this disease and aluminum exposure is inconclusive. Some researchers have found that people exposed to high levels of aluminum can develop AD. However, other researchers have concluded that this is not the case.
Aluminum is a common metal in everyday objects, such as:
food packaging
cooking utensils
certain medications
certain antiperspirants or deodorants
Humans also absorb some aluminum from air, water and soil. Exposure to abnormally high levels of aluminum can be harmful to individuals. However, people generally only absorb very small amounts of this metal. Most people typically have up to 50 micrograms (mcg) of aluminum in their bodies. Some metals, such as zinc, copper and iron, are naturally present in the body. Small amounts of these metals are essential for the proper functioning of the brain and body. Also, the kidneys help remove excess metals from the body. However, in case of kidney failure or exposure to very high doses of aluminum, this metal can accumulate in the brain. This phenomenon may be the cause of AD, although further research is needed to be certain.
What does the research say?
Researchers have done many studies on AD and aluminum. Many of them are now historic. In 1965, researchers discovered that rabbits given aluminum injections developed signs of AD. However, the researchers only saw these signs when they injected rabbits with very high doses. These doses were several times higher than the levels that typically enter the human body.
A 2011 study looked at the link between aluminum and the development of AD. The researchers looked at their own studies and reviewed historical research. They concluded that there was growing evidence of a link between aluminum and Alzheimer’s disease. However, they also noted that the exact cause of Alzheimer’s disease was still unknown.
More recently, Canadian scientists have investigated the links between aluminum in drinking water and AD. They presented their findings in a 2021 study. They found higher levels of aluminum in certain groups of people with AD. However, these people also had a genetic factor already linked to an increased risk of developing Alzheimer’s disease. They did not find an overall link between aluminum in drinking water and the risk of developing the disease.
Scientists explored research on the health effects of aluminum exposure in this 2017 review. They searched for scientific publications on the links between aluminum and health, including associations with AD . They concluded that:
Exposure to extreme levels of aluminum can cause a specific brain condition with symptoms of dementia. However, this brain condition is different from AD.
The brains of people with AD had higher levels of aluminum. They stressed that it was unclear whether this was a cause or an effect of the disease.
Studies looking at the onset of Alzheimer’s disease in populations have not shown clear links between aluminum and the development of Alzheimer’s disease.
Can other heavy metals cause AD?
Other heavy metals can cause Alzheimer’s disease:
the lead
cadmium
manganese
These metals are toxins. Scientists have shown that they contribute to the causes of AD in animal studies. In human studies, scientists have linked these metals to symptoms related to Alzheimer’s disease, such as cognitive decline and trouble thinking. However, in this 2020 study, the scientists noted that no studies have specifically linked these metals to the cause of Alzheimer’s disease. They also recommended further research into possible links.
Is aluminum present in the human brain?
People with healthy brains usually have aluminum in their bodies. A person’s body usually absorbs 10 mg of this metal per day. However, only about 1% of this amount reaches the brain. Although aluminum is toxic, scientists have yet to show that the levels typically found in people’s brains are harmful. Researchers continue to study the exact threshold at which the presence of aluminum in a person’s brain becomes harmful.
In short
Every day, people absorb aluminum into their bodies from the environment, air and food. Although a small amount of this metal reaches brain tissue, typical levels of aluminum in a person’s body are generally not harmful. People with Alzheimer’s disease tend to have higher levels of aluminum in their brains. However, scientists do not yet know whether this is a cause or an effect of the disease. Researchers continue to investigate whether aluminum is the cause of AD.
