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We use aluminum foil in our kitchen for a variety of tasks. From wrapping the food that goes into the fridge to grilling and baking our favorite recipes.
So, our food is in frequent contact with these shiny thin aluminum sheets. However, that triggers some important questions.
Is Aluminum foil safe to use? Which side of aluminum foil is safe to use? Is it safe to bake with aluminum foil?
In this text, I want to touch on all these questions and solve some frequent confusion about aluminum foil safety. To provide you this Information I have summarised the conclusions from more than 10 scientific studies that directly investigate this topic. You can find their full list at the end of the article.
Additionally, I found a lot of blog articles on this subject that haven’t provided accurate information and clear references.
That was an additional reason for me to write down this article and give you some clear directions about aluminum foil safety.
What is aluminum foil exactly? How it is made?
Aluminum foil, sometimes also called tin foil, presents aluminum pressed into thin sheets, less than 0.2 mm thick. The conventional house Al foils are even thicker, usually between 0.016 and 0.024mm.
The whole process of production starts with aluminum alloy ingots as a raw material. As a first step, they are molded and reshaped in large thick sheets. Alloys used for foil production are more than 92% pure aluminum with the addition of some elements like zinc, titanium, and silica.
Further processing takes these sheets through successive press through rolling mills. This process allows the reduction of size up to several micrometers.
But why the Al foil has two different sides?
During the final thickness reduction on the cold rolling mills, it is not feasible to roll just one sheet of aluminum. This could lead to breakage as a consequence of material sensitivity.
Because of this two sheets of aluminum are thickened together in the final processing. So, in the end, the side of sheets that touch another Al sheet become dull side. On the other hand, a surface of foil that is in direct contact with smooth rollers stays shiny.
You can find a good visualization of this process in one of the “How its Made“ episodes below.
https://youtu.be/f4OTj9yNOak?t=105
Is Aluminum toxic? How much we are exposed to it on daily basis?
Since the early 70s researchers started to recognize the link between some serious pathological conditions and aluminum exposure.
Certain aluminum-based medicaments used for the treatment of chronic kidney disease, like phosphate binders, showed direct linkages with bone and neural tissue damage.
From that time different studies on animals and humans were conducted to reveal the consequences behind aluminum exposure. Numerous scientific papers have to dig deeper into the mechanisms behind aluminum toxicity and have provided us more clear knowledge on this topic.
Unlike some other metals, the Al atom is not present as a structural part of any molecule in the human body.
Aluminum exposure in humans has shown genotoxicity and cancerogenic effects. Furthermore, increasing Al levels in the body can trigger problems with the fetus development and different neurological disorders.
Here you can find several comprehensive scientific publications that summarise mentioned consequences of aluminum exposure. (1, 2, 3)
Maximally allowed aluminum uptake
The wave of studies performed at the end of the 20th century pushed Food and Health authorities around the world to establish regulations and prevent people’s exposure to aluminum.
After summarizing all available data and more than a hundred studies the European Food Safety Authority have set the limit of aluminum intake at 1mg per kilogram of body weight, per week. (4.) That is around 10mg a day for a 70kg person.
The Food and Drug Administration (FDA) and World Health Organization (WHO) agreed that levels below 2 mg per 1 kg of body weight are safe for humans (5.).
The main problem with using aluminum foil is that it can release significant amounts of this metal into the food.
But, before I start to talk about the significance of aluminum transfer, I would like to define what I mean by “significant leaking”.
As a “significant“ I consider Aluminum concentrations of more than 5 mg per food portion (125g), raised as a consequence of contact with aluminum foil.
If we take this amount into the context of the daily limitation set by EFSA (10mg 70kg person daily), 5mg presents 50% which is fairly significant.
Furthermore, there are many other serious sources of Al that we are in contact with, apart from food(e.g. water, medicaments, vaccination). These additional streams can highly contribute to overcoming daily aluminum limits.
Sources of expositure
The main issue with aluminum is that there is no just one stream of exposure. Our body intakes this metal from all kinds of sources. Some of the main are:
- Drugs– e.g.aluminum-based antacids and phosphate binders (6.)
- Raw food- Different food items like tea or spices have high amounts of Al(7. ). Find the list of some common food ingredients reach in the Al bellow
- Food additives– One of the studies estimates that the average US citizen consumes 24mg of the Al through food additives.(8.) Different aluminum-based additives are in frequent use even today e.g. E 173, E520, E 521, E 522, E 523, E 541, E 554 E 555, E 556, E 558, E 559, E 1452(9.)
- Cookware and packaging materials-this includes usage of aluminum foil and aluminum cookware. Aluminum utensils are particularly popular in the developing countries of the world where this source of aluminum intake can be highly significant.
- Water
According to EFSA comprehensive Aluminum toxicity report, the average daily intake in evaluated European countries varies from 0.2 to 1.5 mg/kg Bw/week. The data was collected based on Netherlands, Hungary, Germany, Sweden, Italy, UK, Finland, and France.(4.)
This indicates that the limited aluminum intake level of 1mg/kg of body weight per week is already overreached. So, any extensive use of aluminum items only adds up to these existing streams.
*Below see the table with some commonly consumed kitchen ingredients that consist of High Al content.
* reference for ingredients marked with number 1 is (14.), reference for items marked with number 2 (16.)
Is it safe to wrap food in aluminum foil?
Aluminum foil is used for different applications in the kitchen. Common practices include practices like storing the food leftovers wrapped in aluminum foil, preparing meat cuts for the grill to keep them moist, or using it for wrapping the dishes in the oven.
But do these practices lead to significant leaching of aluminum into our food?
The studies found that this depends on several important factors. In the first place cooking duration, heating temperature, composition, food pH value, and presence of any other substances (such as organic acids and salt) (8.1). In some cases, the answer is Yes.
Generally, food ingredients with acidic pH like marinades, lemon, vinegar, wine, tomato sauce fruit sauces, and others can contribute to significant leaking of the aluminum into food. Also, exposing wrapped food to heat(ovens or grill) contributes to the leaching of potentially harmful amounts of Al.
So let’s go through some studies that have evaluated this.
What experiments reveal?
A good example is a study from 2019 that investigated the Al leaching into different marinated meat cuts baked in aluminum foil. They have found that some meet samples prepared on this way can reach around 50mg of aluminum per kg of food. (10. )
This means that the portion of around 200g of the meet will exceed the daily aluminum limit for 70kg person set by EFSA.
Even some earlier studies like one done by Sadettin Turhan in 2006 have shown the presence of Al levels of up to 60mg per kg of foil-wrapped prepared in similar conditions (11. ).
Notes: In last mentioned study the researchers summarized that there is no significant aluminum leaching from foil to meet. The reason is that in 2006. maximally allowed Al doses were 10 times lower compared to the limits today. Making more strict regulation have raised as a consequence of new data that confirm even higher aluminum toxicity levels.
One of the research programs in Nigeria shows that after baking the beef in duration from 1-3 hours on 100C in aluminum foil. They find that even after 1 h out the level of the aluminum in beef reaches 59mg/per kilogram.
Baking the same beef with the knorr dressing resulted in 84mg/kg of aluminum. Finally, by increasing the duration of cooking to 3 h they find that aluminum content rises more than three times(12).
Some of the research studies done on this topic haven’t shown aluminum leaching as high as in previously mentioned reports(13,14). However, there is a sufficient amount of data that indicates that Al leaching from foil can be significant, as presented.(10,11, 12)
In conclusion, it is important to avoid practices that trigger significant Al leaching from the foil. Apart from this, there are other steps that you can take. For all of the details see the chapter “How to reduce daily exposure to Al”.
How to judge are research studies relevant?
It is important to have the criteria when reading different scientific articles. For instance, some of them come to the conclusion that Al leaching from the foil is not significant based on aluminum regulations in the past.
It is essential to look at the date of the studies. Earlier regulations were far less strict. So, it is important to know does study comes up with conclusions considering the present EFSA and FDA regulations.
Finally, it is good to take into account only the studies that applied real-life conditions when making an experiment with aluminum foil. For instance, one study from 2012 found extremely high aluminum levels in food after being in contact with aluminum foil. (15. )
But how they conducted the experiment?
They immerse the Al foil in the food liquid solution for several hours. Furthermore, they added 20g of citric acid to 250ml of the dish which drops the Ph significantly which also triggers strong aluminum leaching.
These conditions are totally irrelevant in the context of everyday aluminum foil use. Furthermore, studies like this should not be taken into account when trying to get conclusions.
How to reduce the daily exposure to Al?
As I mention earlier maximal daily aluminum intake of around 10mg for 70kg person is already fulfilled through sources like food, water, additives, and medicaments. Because o that it is important to take the steps and avoid any additional Al exposure.
When using aluminum foil there are several commonly used practices that are good to avoid:
Ø Baking acidic ingredients in the aluminum foil. (e.g. tomato sauce, lemon, vinegar, wine, etc..)
Ø Grilling the meat wrapped in the aluminum foil
On the other hand, certain aluminum foil applications won’t lead to the leaching of significant Al amounts to your food. So, it is ok to use them:
⊕ Baking the neutral ingredients wrapped in the aluminum foil.
According to my knowledge, no study has shown leaching of significant Al amounts in this case. This includes all of the studies that I mentioned in this article
⊕ Storing the food in the refrigerator or room temperature without heating.
⊕ Other applications that do not include heating
Extra steps to avoid aluminum exposure
Apart from aluminum foil, there are some other great ways to reduce daily aluminum uptake:
1. Decrease everyday consumption of Aluminum reach food in high quantities
(look at the list presented earlier in the text)
2. Avoid using aluminum-based medicaments – antiacids(a common way of high aluminum exposure). Also in the case of treating chronic kidney avoid aluminum-based phosphate binders.
3. Keep away from consuming the processed food (e.g. Frozen pizzas, and other ready-to-use food..). Instead, try to eat freshly prepared dishes. Notice does your food contain Al-based additives E 173, E520, E 521, E 522, E 523, E 541, E 554 E 555, E 556, E 558, E 559, E 1452
4. Avoid using Al cookware
Frequently asked questions
There are some questions that I often hear bout aluminum foil toxicity so I would like to give a direct answer to them and to provide more specific info for each case.
Which side of aluminum foil is toxic?
Both sides of aluminum foil produce the same effects. Independent of the side that you use, wrapping the food in aluminum foil can contribute to significant Al leaching and negative effects on health. See more in the article.
In one of the scientific papers done on the topic of aluminum foil toxicity the researchers conclude:
,, As previously reported by Ranau et al. (2001) we agree that the side (shiny/dull) of aluminum foil in contact with food did not influence the increase in food aluminum concentration, although our experiments on this topic are not included in this paper”(17.)
Is safe to cook with aluminum foil in the oven?
It depends on the food you cook. According to the research, cooking food that includes acidic ingredients like winger or lemon wrapped in aluminum foil can lead to significant aluminum leaching into the food. A few studies have shown that these concentrations can reach 50mg of aluminum per Kg of food.
This means that if you consume 100-200g of dish you will be exposed to 5-10mg of aluminum. If we take into consideration that the concentration proposed by European Food Authority Organisation is 10mg per kg of body weight in the case of 70kg person, this amount is more than significant.
Which temperature aluminum foil si safe to?
Aluminum foil is safe to use in the whole range of temperatures applied in the conventional stoves( up to 250C) if you avoid certain practices. Using aluminum foil to wrap acidic foods(e.g. marinated meat or lemons) leads to aluminum leaching that can negatively affect health. .(10, 11, 12).
References
Bassioni, Ghada, Fathia S. Mohammed, Essam Al Zubaidy, and Issam Kobrsi. 2012. “Risk Assessment of Using Aluminum Foil in Food Preparation.” Int. J. Electrochem. Sci. 7:13.
Cuciureanu, R., A. Urzică, M. Voitcu, and A. Antoniu. 2000. “[Assessment of daily aluminum intake by food consumption].” Revista Medico-Chirurgicala a Societatii De Medici Si Naturalisti Din Iasi 104(3):107–12.
Dordevic, Dani, Hana Buchtova, Simona Jancikova, Blanka Macharackova, Monika Jarosova, Tomas Vitez, and Ivan Kushkevych. 2019. “Aluminum Contamination of Food during Culinary Preparation: Case Study with Aluminum Foil and Consumers’ Preferences.” Food Science & Nutrition 7(10):3349–60. doi: 10.1002/fsn3.1204.
Ekanem, E. J., J. A. Lori, F. G. Okibe, G. A. Shallangwa, B. A. Anhwange, M. Haliru, and A. A. Moyosore. 2009. “Determination of Aluminium in Different Sources and Its Contribution to Daily Dietary Intake in Nigeria.” 6.
Ertl, Kathrin, and Walter Goessler. 2018. “Aluminium in Foodstuff and the Influence of Aluminium Foil Used for Food Preparation or Short Time Storage.” Food Additives & Contaminants: Part B 11(2):153–59. doi: 10.1080/19393210.2018.1442881.
European Commission. Directorate General for Health and Food Safety. 2017. Final Opinion on Tolerable Intake of Aluminium with Regards to Adapting the Migration Limits for Aluminium in Toys. LU: Publications Office.
Greger, J. L. 2007. “Dietary and Other Sources of Aluminium Intake.” Pp. 26–49 in Novartis Foundation Symposia, edited by D. J. Chadwick and J. Whelan. Chichester, UK: John Wiley & Sons, Ltd.
Greger, J. L., and M. J. Baier. 1983. “Excretion and Retention of Low or Moderate Levels of Aluminium by Human Subjects.” Food and Chemical Toxicology 21(4):473–77. doi: 10.1016/0278-6915(83)90105-9.
Ranau, R., J. Oehlenschläger, and H. Steinhart. 2001. “Aluminium Levels of Fish Fillets Baked and Grilled in Aluminium Foil.” Food Chemistry 73(1):1–6. doi: 10.1016/S0308-8146(00)00318-6.
Reinke, Claudia M., J??rg Breitkreutz, and Hans Leuenberger. 2003. “Aluminium in Over-the-Counter Drugs: Risks Outweigh Benefits?” Drug Safety 26(14):1011–25. doi: 10.2165/00002018-200326140-00003.
Turhan, Sadettin. 2006. “Aluminium Contents in Baked Meats Wrapped in Aluminium Foil.” Meat Science 74(4):644–47. doi: 10.1016/j.meatsci.2006.03.031.
