Can aluminum be absorbed through the skin

Health risks

A distinction is made between aluminum health risks

  • "Remote" applications (e.g. in automotive engineering) and
  • "Body-hugging" applications (e.g. food).

In the case of remote applications, absorption into the body is unlikely or impossible. On the other hand, in the case of products that are close to the body, absorption of aluminum into the body is possible or even - in the case of drugs - intended.

Toxicity of aluminum

Aluminum compounds are only slightly absorbed through the skin. Investigations under in vivo conditions showed that only a little more than the ten thousandth part of the applied amount can pass the skin barrier (Flarend and coworkers, 2001). A maximum of one hundredth of the amount absorbed is absorbed via the gastrointestinal tract, whereby citrate and ascorbate (vitamin C) can facilitate absorption (BfR 2014).

Overall, the acute toxicity of aluminum is low.

If high doses are administered via the bloodstream, i.e. bypassing the gastrointestinal tract, neurotoxic effects, e.g. in the form of dialysis encephalopathy, can occur.

Aluminum is able to cross the blood-brain barrier. Whether there is a causal connection between increased aluminum intake and Alzheimer's disease is scientifically controversial. The World Health Organization denied this connection in 1997.

The well-known interaction between aluminum and the phosphate and calcium metabolism can lead to osteomalacia (softening of the bones).

Aluminosis (aluminum dust lung) is known from occupational medicine.

Risk factors

Aluminum can build up in the body if the protection provided by the gastrointestinal barrier can be bypassed, if the kidneys are not working properly, or if exposure is high. Aluminum may also have health effects in small amounts (taken over a long period of time).

Aluminum intake through food

Orally ingested aluminum compounds are hardly absorbed enterally (only approx. 0.1-1%). Complexing agents such as citrates, however, can increase this absorption to around two to three percent.

As a rule, aluminum is excreted through the kidneys. This process is not fully possible in people with impaired kidney function.

The light metal is deposited in the body, especially in the lungs and bones. In the bones, aluminum has a direct toxic effect on osteoblasts and also disrupts mineralization. Further deposits are possible in the brain, in the spleen and in the liver. Aluminum can cross the blood-brain barrier as aluminum citrate or as transferrin-bound aluminum.

The BfR does not rule out a causal connection between aluminum and Alzheimer's disease and / or breast cancer (BfR 2014). So far, however, the study situation is still unsatisfactory.

In particular, the connection between aluminum and Alzheimer's disease is repeatedly discussed in science. While aluminum was considered a risk factor in the 1970s and 1980s, it was believed in the 1990s that there was no connection.

There are now new methods for determining aluminum ions. A study by Italian scientists from 2013 found that the so-called ferritin (protein complex that serves as iron store) in Alzheimer's patients does not primarily store iron, but aluminum.

These results again suggest a connection between aluminum and Alzheimer's disease. However, the study was only carried out on a small scale, so that in larger studies it must first be examined whether these results can be generalized.

Compared to adults, children eat more food in relation to their body weight. Because of this, children (including infants) are more likely to be affected by dietary aluminum exposure. Research studies show that baby and follow-on formulas are much more contaminated with aluminum than breast milk.

The amount of aluminum released into food through food contact materials is considered to be harmless to health. Nevertheless, regular contact with strongly acidic or salty foods / drinks with aluminum-containing materials is not recommended.

Aluminum absorption through drinking and mineral water

Since aluminum is one of the main components of the earth's crust, the drinking water can contain small amounts of aluminum due to dissolved minerals (approx. 0.01 - 0.1 mg / l). However, aluminum mainly gets into drinking water through water treatment, since flocculants containing aluminum are used here. In Germany, however, these funds are usually removed again.

Epidemiological studies indicate a connection between an increased aluminum content in drinking water (above 0.1 mg / l) and Alzheimer's disease. It is assumed that the reason for this is that aluminum dissolved in water can easily reach the brain (Austrian Federal Ministry for Health 2014).

Aluminum oxide is approved for fluoride removal in natural mineral water (EU Regulation No. 115/2010). Residues that pose a public health risk must not be left behind.

The fluoride removal must be reported to the authorities and the treated water must be labeled with the addition “This water has been subjected to an approved adsorption process” (Austrian Federal Ministry of Health 2014).

Aluminum intake through medication

So-called antacids are often used in medication for heartburn and stomach problems. These can contain aluminum compounds. If you take the maximum recommended daily dose, your daily aluminum intake can increase by 5000 mg. Aluminum compounds ingested by antacids are to a small extent absorbed. They can get into organs and bones via the bloodstream. The connection between aluminum-containing drugs and Alzheimer's disease, as well as between aluminum-containing drugs and food allergies, is controversial.

Since aluminum can reach the fetus via the placenta, these drugs should not be used or only rarely taken during pregnancy.

Antacids containing aluminum should only be taken if clearly indicated and with a prescription (Austrian Federal Ministry of Health 2014).

Aluminum uptake via therapy allergens

The Paul Ehrlich Institute received an increasing number of inquiries about possible risks from aluminum in therapy allergens. The statement can be found here.

Aluminum intake via cosmetics

The dietary intake of aluminum has been well studied. In contrast, little is known about the absorption of aluminum through the skin.

Research studies with aluminum-containing antiperspirants have shown that aluminum is absorbed through the human skin. Exposure increases significantly when there is damage to the skin. However, the question of how much of the applied aluminum actually gets into the bloodstream remains open. Further epidemiological studies are necessary here. Individual differences in the absorption of aluminum are conceivable.

There is no clear causal relationship between aluminum-containing cosmetics and breast cancer, Alzheimer's disease, Parkinson's disease or other neurodegenerative diseases.

According to current studies, aluminum cannot be considered safe in cosmetic products. However, the Scientific Committee on Consumer Safety (SCCS for short) has come to the conclusion that too little data is available to be able to carry out a complete risk assessment.

Aluminum intake at workplaces

In (industrial) workplaces, the risk of illness from inhalable aluminum dust is high. In particular when welding and grinding, breathing in fine aluminum particles can cause lung damage. The production of metallic aluminum flakes (so-called “pyro powder”) is also questionable.

Epidemiological studies provide evidence of nerve and brain damage in workers who have been exposed to aluminum through vapors or dust over a long period of time (Austrian Federal Ministry of Health 2014).

Aluminum intake with parenteral nutrition (PN; artificial nutrition in which the digestive tract is bypassed)

In premature infants who are parenterally fed, all risk factors of aluminum exposure come together. The data from the study by Fewtress et al. (2011) show that aluminum intake in PN in the high-risk group of premature infants can have negative effects on the later health of the bones as well as short-term effects on cognitive performance.

excretion

Aluminum is mainly excreted in stool and urine. Skin (sebum), hair, nails, sperm and sweat are also possible exit routes.

Over 95% of the aluminum ingested is excreted through the kidneys. That explains why people can deal with increasing aluminum intake. The risk of aluminum accumulation in the body is minimized, but not eliminated (Kramer & Heath 2014).