A short GreenFacts overview of three health assessments related to aluminium exposure and aluminium products :
2) the statement of EFSA on the Evaluation of a new study related to the bioavailability of aluminium in food ;
3) the Risk assessment by the French Agency AFSSAPS related to the use of aluminum in cosmetic products.
1. In summary
Based on the the available scientific data, the EFSA  Panel does not consider exposure to aluminium via food to constitute a risk for developing Alzheimer’s disease despite the fact it has been suggested that aluminium could be implicated in the aetiology of Alzheimer and other neuro-degenerative diseases. EFSA also considers unlikely aluminium to be a human carcinogen at dietary relevant doses.
The EFSA Panel established a Tolerable Weekly Intake of 1 mg aluminium/kg body weight/week. Recently, EFSA evaluated a new study (2011) on the oral absorption of a various aluminium compounds and considered that the results did not provide any additional information that could modify their conclusions reached in 2008. EFSA also considered that the Tolerable weekly Intake of 1 mg/kg body weight/week is likely to be exceeded in a significant part of the European population The French Agency AFSSAPS evaluated the exposure and the potential health effects related to dermal exposure. Their conclusion was that there are insufficient data to establish a clear relationship between the use of underarm aluminum-based antiperspirants and breast cancer. In this context, AFSSAPS recommends to restrict the concentration of aluminum in cosmetic products at 0.6% and not to use cosmetics containing aluminum on damaged skin.
2. Identification of the Tolerable limit (hazard threshold )
The limit of 1 mg aluminium / kg body weight / week is in line with that set in 2006 by the Joint FAO / WHO (JECFA) expert committee , which had already reassessed the 1989 Provisional Tolerable Weekly Intake (PTWI) based on studies particularly cited by IPCS (1997) and TOC 5 (2005). To assess the maximum tolerable level, JECFA noted that no new data really emerged since the 1989 assessment and had retained the option to refer to the range of values (50-75 mg / kg bw / day) representative data from the literature rather than to the results of any specific study. This led to define a new TWI of 1 mg / kg bw / week (Al), value taking into account a safety factor of 100 and accompanied by an uncertainty factor of 3 for the potential for bioaccumulation. This TWI applies to all aluminum compounds present in food, including food additives.
3. Evaluation of the risk level compared to the hazard threshold
3.1. Dietary exposure
EFSA considers that the Tolerable weekly Intake of 1 mg/kg body weight/week is likely to be exceeded in a significant part of the European population. Regarding exposure data to aluminum of the French population from food, in 2008, the French Agency of Food Safety AFSA, showed that the potential risk of overexposure is low. Indeed, the estimated total intake alulminium, all food categories combined, remains below the TWI of 1 mg / kg bw / week, whatever the categories of the population concerned, including infants.
3.2. Dermal exposure
The French agency AFSSAPS recommends to restrict the concentration of aluminum in cosmetic products at 0.6% and not to use cosmetics containing aluminum on damaged skin.
4. About the potential health effects of aluminium
Based on the the available scientific data, the EFSA Panel does not consider exposure to aluminium via food to constitute a risk for developing Alzheimer’s disease despite the fact it has been suggested that aluminium could be implicated in the aetiology of Alzheimer and other neuro-degenerative diseases. In the meantime, the Panel considered it prudent to take into account, when setting a tolerable intake for all dietary sources, that several compounds containing aluminium showed in experimental tests in animals the potential to produce neurotoxicity, to affect the male reproductive system and, after maternal exposure, have shown embryotoxicity and have affected the developing nervous system in the offspring. Although at high levels of exposure, some aluminium compounds may produce DNA damage, the Panel considered this unlikely to be of relevance for humans and also concluded that aluminium is unlikely to be a human carcinogen at dietary relevant doses. On basis of these conclusions of EFSA, very recently (2011) , the French Agency AFSSAPS evaluated the exposure and the potential health effects related to dermal exposure and concluded that there are insufficient data to establish a clear relationship between the use of underarm aluminum-based antiperspirants and breast cancer.
5. Recommended Limits of exposure for Aluminium compounds
It is in view of the cumulative nature of aluminium in the organism after dietary exposure that the EFSA Panel considered it more appropriate to establish a Tolerable Weekly Intake (TWI) for aluminium rather than a Tolerable Daily Intake (TDI). Based on the combined evidence from the above mentioned studies, the Panel established a TWI of 1 mg aluminium/kg body weight/week, in line with the JEFCA decision  Ther French ganecy AFSSAPS considered that their risk assessment for dermal exposure shows that exposure to antiperspirant products with concentrations of 20% aluminum chlorohydrate does not ensure consumer safety under normal conditions of use. In addition, as their present risk assessment does not take into account the total exposure to various cosmetic products likely to contain aluminum, their conclusions are subject to change. On this basis, the AFSSAPS recommends to restrict the concentration of aluminum in cosmetic products to 0.6% and not to use cosmetics containing aluminum on damaged skin. The AFSSAPS also recommends this information to be clearly indicated on the packaging.
6. Sources of aluminium exposure
6.1. Dietary sources.
According the the EFSA report (2008), the estimated mean daily dietary exposure to aluminium in the general population, assessed in several European countries, was up to 2.3 mg/kg bw/week in highly exposed consumers and the Tolerable Weekly Intake of 1 mg/kg bw/week is therefore likely to be exceeded in a significant part of the European population. According to the same report, a variety of aluminium compounds are indeed produced and used for different purposes, such as in water treatment, papermaking, fire retardant, fillers, food additives, colours and pharmaceuticals. Aluminium metal, mainly in the form of alloys with other metals, has many uses including in consumer appliances, food packaging and cookware. The major route of exposure to aluminium for the general population is through food. Most unprocessed foods typically contain less than 5 mg aluminium/kg. Higher concentrations (mean levels 5 to 10 mg/kg) were often found in breads, cakes and pastries (with biscuits having the highest levels), as well as some vegetables (with mushrooms, spinach, radish, …)
Cereals and cereal products, vegetables, beverages and certain infant formulae appear to be the main contributors to the dietary aluminium exposure. Meanwhile, it is not possible, says the report, to conclude on the specific sources contributing to the aluminium content of a particular food, such as the amount inherently present, the contributions from use of food additives, and the amounts released to the food during processing and storage from aluminium-containing foils, containers, or utensils. Thus a detailed breakdown by exposure source is not possible. Aluminium in drinking water represents another minor source of exposure says the report. Additional exposures may arise from the use of aluminium compounds in pharmaceuticals and consumer products.
6.2. Dermal exposure
The absorption of aluminum after dermal exposure was recently examined by the AFFSAPS. This absorption is very poorly understood,says the report, as the available studies are of poor quality and are not carried out according to the current requirements. Meanwhile, recent in vitro study on human skin via two scenarios (intact and damaged skin) allowed to estimate the dermal absorption of aluminum via a daily exposure to an antiperspirant containing 20% of aluminum chlorohydrate (5% aluminum). The exposure of intact skin would lead to a dermal absorption rate of 0.5% while exposure of damaged skin would result in an absorption rate of 18%. This would lead to a margin of safety is 11 in intact skin exposure conditions and less than 1 in the case of damaged skin exposure conditions.
7. The fate and availability of aluminium in the human body
The absorption, distribution and elimination properties of aluminium (called its “bioavailability”) and several aluminium compounds in humans and experimental animals have been reviewed extensively and summarized in the EFSA report. Available studies indicate that the oral bioavailability of aluminium in humans and experimental animals from drinking water is approximately 0.3%, whereas the bioavailability of aluminium from food and beverages generally is considered to be lower, about 0.1%. However, it is likely, says the report, that the oral absorption of aluminium from food can vary at least 10-fold depending on the chemical forms present in the intestinal tract. Globally, the total body burden of aluminium in healthy human subjects has been reported in Europe to be approximately 30–50 mg/kg bw. Absorbed aluminium is eliminated primarily by the kidneys, presumably as aluminium citrate, and excreted in the urine. Unabsorbed aluminium is excreted in the faeces
A recent study on aluminium bioavailability did not change the Opinion of EFSA The results from a recent study (2011) showed that the oral bioavailability of aluminium from twelve different aluminium-containing compounds, including food additives falls within the overall 10-fold range of previously reported oral bioavailability values for aluminium containing compounds. Therefore, EFSA considered that the new study does not provide any additional information that could modify the conclusions reached in 2008 and does not give reason to reconsider the previous safety evaluation of aluminium-based food additives authorised in the European Union.
8. About aluminium
Aluminium occurs naturally in the environment, and is the most abundant metallic element in the earth’s crust. The naturally occurring stable isotope is 27Al. The isotope 26Al has a long half life but a low natural abundance and is used as a tracer in biological studies. Aluminium is only found in nature as Al3+.