FULL CLAIM: “Heat causes aluminum to ‘leach foil’ to food leading to Alzheimer’s and cancer [...] Aluminum builds up in the brain and causes Dementia and Alzheimers.”
REVIEW
Aluminum is a metal abundant in our daily environment. It’s the most predominant metal in the earth’s crust and is present in air, water, and the human body. We’re exposed to trace amounts of aluminum in our diet from things like tea, spices, and meats, as well as in processed foods and additives. The body removes these trace amounts of dietary aluminum by processing them through the kidneys and excreting them in stool.
Claims that aluminum foil poses health risks circulate intermittently on social media. These claims date back as early as 2016, when headlines in the Daily Mail and the Evening Standard suggested that cooking with aluminum foil could be linked to diseases including Alzheimer’s and osteoporosis.
A Facebook post shared in March 2024 revived this claim, asserting that heat causes aluminum to leach into food and that this can lead to Alzheimer’s and cancer.
As we will explain below, there is currently no strong evidence to suggest that cooking with aluminum foil can cause adverse health effects.
Aluminum exposure is part of daily life; small amounts aren’t harmful
According to the Canadian Centre for Occupational Health and Safety, exposure to aluminum occurs in a number of ways:
“In addition to workplace exposure, people can come into contact with aluminum in many other ways […] Aluminum is found in food, drinking water and in some medications. […] The Alzheimer Society of Canada notes that the ingestion of aluminum in cookware and other products as a route of exposure is considered to be a very small percentage of the average person’s intake of aluminum, and that it would be difficult to avoid this exposure.”
Estimates for average aluminum intake vary due to differences in individual diets. One review suggested it ranges between 0.2 to 1.5 milligrams per kilogram of body weight per week for adults[1].
Given that dietary aluminum intake may differ from person to person, health and regulatory agencies have set a tolerable weekly intake (TWI) of one milligram of aluminum per kilogram of body weight. Agencies that suggest this TWI include the Scientific Committee on Food of the European Commission, and the Joint Expert Committee on Food Additives of the Food and Agriculture Organization and the World Health Organization.
Aluminum levels in food may increase when foods are cooked in foil, but these amounts fall within tolerable limits
Studies replicating real-world conditions of cooking with aluminum foil found there were no evident health risks associated with this cooking method[2,3,4]. The studies evaluated how much aluminum was transferred to a range of foods including meats, fish, starches, and vegetables and whether this changed depending on the cooking temperature and duration.
The studies generally found an increase or “contamination” of food with aluminum when it was prepared using aluminum foil, which is likely the basis for the claim that cooking with aluminum foil isn’t safe.
The variables listed above, including differences in food types, quantities, preparation methods, and cooking times and temperatures, all led to differences in the amount of aluminum measured in the final cooked products. But even accounting for these differences, the studies concluded that the amount of aluminum “transferred” from foil to foods fell within the TWI of 1 mg Al/kg of body weight.
In one study, for example, fish filets were grilled and baked in aluminum foil with and without ingredients like onion rings, vinegar, and mixed spices[2]. Findings stated:
“The increase in aluminium concentration ranged from a factor of 2 (baked saithe fillets without ingredients from 0.10 up to 0.21 mg/kg) to a factor of 68 (grilled mackerel fillets with ingredients from 0.07 up to 5.04 mg/kg). […] Presumably two factors were responsible for the higher aluminium contents in grilled fillets: first the higher temperature of preparation when grilling fillets and second the high aluminium content of mixed spices (63.5 mg Al/kg).”
To put this in perspective, an average adult weighing 70 kilograms could consume up to 70 mg of aluminum per week based on the TWI of 1 mg/kg.
Based on the findings from this study, this would mean that adult would need to eat at least 14 kg of grilled mackerel filets—the fish that presented the highest aluminum concentration in this particular study—to exceed the TWI (70 mg/kg aluminum limit/5.04 mg/kg = approximately 14 kg of grilled mackerel filets). Assuming a rather large serving size of mackerel at 500g per serving, this would amount to 28 servings of grilled mackerel per week, or four servings of mackerel per day—a quantity unlikely for any person to consume as part of a balanced diet.
In another study, beef round roast, flounder, potatoes, and turkey were frozen, baked, and reheated in foil for varying lengths of time. All had aluminum levels of less than 0.4 milligrams per kilogram of food weight after being cooked in foil[5].
And in another study, a variety of foods cooked in aluminum foil including meats, fish, cheese, and vegetables found that levels of aluminum contamination were “not alarming”[3].
In brief, the amount of aluminum transferred during the cooking process from products like foil constitutes a small percentage of total dietary aluminum consumed. Based on tolerable limits set by regulatory and health agencies, these amounts are unlikely to lead to health problems.
Aluminum foil use not linked to cancer or Alzheimer’s
In their report “Safety of aluminum from dietary intake”, a panel of scientists commissioned by the European Food Safety Authority (EFSA) defined dietary intake of aluminum to include food and products used for “food processing, packaging and storage”, such as aluminum foil. The report stated:
“Under normal and typical conditions the contribution of migration from food contact materials would represent only a small fraction of the total dietary exposure.”
The report also stated that aluminum is “unlikely to be a human carcinogen at dietary relevant doses”, and commented on aluminum’s purported link to Alzheimer’s disease:
“It has been suggested that [aluminum] is implicated in the [etiology] of Alzheimer’s disease and associated with other neurodegenerative diseases in humans. However, these hypotheses remain controversial. Based on […] the available scientific data, the Panel does not consider exposure to [aluminum] via food to constitute a risk for developing Alzheimer’s disease.”
For context, the claim that aluminum causes Alzheimer’s can be traced back to a 1965 animal study[6]. According to the Alzheimer’s Society, researchers conducting the study found that:
“[R]abbits injected with aluminum developed toxic protein tangles in their brains. This led to speculation that aluminum from cans, cookware and even the water supply could be causing dementia. Importantly, these results were only seen with extremely high doses – far more than we normally get from our environment.”
However, a later study found that these protein tangles were “very biologically different to the tangles and fibres found in the brains of people with Alzheimer’s disease”, according to the dementia research charity Alzheimer’s Research UK.
And the claim that aluminum causes cancer may stem from the claim that aluminum in antiperspirants increases risk of breast cancer. However, there is no strong evidence to date confirming a link between antiperspirant use and breast cancer, and it’s worth noting that applying an antiperspirant to the skin differs from consuming dietary aluminum. As explained by the EFSA report referenced above, exposure to dietary aluminum is unlikely to cause adverse health effects.
Conclusion
Studies have found that quantities of aluminum “leached” into foods when cooked in aluminum foil are minimal and that cooking food in foil doesn’t present any evident health risks. Moreover, health and research agencies have stated that aluminum from dietary intake is unlikely to be carcinogenic or to cause Alzheimer’s disease.
REFERENCES
- 1 – Stahl et al. (2018) Evaluation of human exposure to aluminum from food and food contact materials. European Food Research and Technology.
- 2 – Ranau et al. (2001) Aluminium levels of fish fillets baked and grilled in aluminium foil. Food Chemistry.
- 3 – Dordevic et al. (2019) Aluminum contamination of food during culinary preparation: Case study with aluminum foil and consumers’ preferences. Food Science & Nutrition.
- 4 – Turhan S. (2006) Aluminium contents in baked meats wrapped in aluminium foil. Meat Science.
- 5 – Greger et al. (1985) Aluminum Levels in Foods Cooked and Stored in Aluminum Pans, Trays and Foil. Journal of Food Protection.
- 6 – Klatzo et al. (1965) Experimental Production of Neurofibrillary Degeneration: I. Light Microscopic Observations. Journal of Neuropathology & Experimental Neurology.
