Scientists have not yet conclusively discovered whether aluminum causes Alzheimer’s disease. Historical research suggests this metal may be a factor. However, some modern researchers disagree.

Alzheimer’s disease (AD) is a brain condition that leads to memory loss and thinking problems. It eventually affects a person’s ability to carry out simple tasks. AD is the most common cause of dementia in older adults.

Scientists do not yet fully understand what causes Alzheimer’s, although risk factors may include:

  • age-related changes in a person’s brain
  • an individual’s genetic or family history
  • a person’s environment

This article discusses historical and current research into the link between aluminum and AD and if other heavy metals can cause AD.

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Scientists do not know for certain if aluminum causes people to develop AD. To date, research examining the link between the condition and aluminum exposure is inconclusive.

Some researchers found that people with exposure to high levels of aluminum may develop AD. However, other researchers found this to be untrue.

Aluminum is a common metal in everyday items, such as:

  • food packaging
  • cookware
  • some medications
  • some antiperspirants or deodorants

People also absorb a certain amount of aluminum from the air, water, and soil. Exposure to unusually high levels of aluminum can be harmful to individuals.

However, people typically only absorb very small amounts of this metal. Most generally 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 to keep people’s brains and bodies working properly.

Additionally, the kidneys help remove excess metals from a person’s body. However, if someone experiences kidney failure or exposure to very high doses of aluminum, this metal can build up in their brain.

This may cause people to develop AD, although more research is necessary to determine this fully.

Researchers have completed multiple studies on AD and aluminum. Many of these are now historical.

In 1965, researchers found that rabbits receiving injections of aluminum developed signs of AD. However, the researchers only found these signs when they injected rabbits with very high doses. These doses were many times higher than the levels that typically enter the human body.

This 2011 study investigated the link between aluminum and the development of AD. The researchers looked at their own studies and reviewed historical research. They concluded there was growing evidence of a link between aluminum and AD. However, they also noted that the exact cause of AD was still unknown.

More recently, Canadian scientists studied the links between aluminum in drinking water and AD. They outlined their findings in a 2021 study.

They found higher levels of aluminum in some groups of people with AD. However, these individuals also had a genetic factor that already had links to an increase in the risk of developing AD. They found no overall association between aluminum in drinking water and the risk of developing the disease.

Scientists explored research into the health effects of aluminum exposure in this 2017 review. They searched scientific publications on aluminum links to health, including associations with AD. They concluded that:

  • Exposure to extreme levels of aluminum can cause a specific brain condition with dementia symptoms. However, this brain condition was different from AD.
  • The brains of people with AD had higher levels of aluminum. They pointed out that it was unclear if this was a cause or an effect of the condition.
  • Studies that investigated how AD occurred in populations of people did not show clear links between aluminum and the development of AD.

In contrast, the author of this 2011 review of others’ research disagreed. They described previous research that appeared to support the theory that aluminum significantly contributes to people developing AD. The author also suggested that a comprehensive evaluation of the overall effect of aluminum on human health was long overdue.

Other heavy metals may cause AD, such as:

  • lead
  • cadmium
  • manganese

These metals are toxins. Scientists have shown they contribute to the causes of AD in animal studies. In human studies, scientists associated these metals with symptoms relating to AD, such as cognitive decline and problems with thinking.

However, in this 2020 study, scientists noted that no study has specifically linked these metals to causing AD. They also recommended further research into any links.

People with typical healthy brains usually have aluminum in them. A person’s body typically absorbs 10 mg of the metal every day. However, only around 1% of this reaches their brain.

Although aluminum is toxic, scientists have not yet shown the levels typically in people’s brains to be damaging. Researchers continue to investigate the exact threshold at which aluminum in a person’s brain becomes harmful.

Every day, people absorb aluminum into their bodies from the environment, air, and food. While a small amount of this metal reaches their brain tissues, the typical levels of aluminum in a person’s body are generally not harmful.

People with AD tend to have higher levels of aluminum in their brains. However, scientists do not yet know whether this is a cause of the condition or an effect.

Researchers are continuing to investigate if aluminum causes AD.