Drinking from aluminum cans exposes you to small amounts of chemicals and metals that would not be present if the same beverage came in glass, but for most people the doses involved fall within regulatory safety limits and pose no immediate health threat. The real picture is more complicated than a simple safe-or-not verdict, though. The interior coating of the can, the aluminum itself, the temperature and age of the drink, and even the grime on the outside of the lid all contribute different risks worth understanding on their own terms.
What You Are Actually Drinking From
When you sip from an aluminum can, your beverage has been sitting against a thin polymer lining, not bare metal. Virtually all food and beverage cans produced today are coated on the inside with a layer of epoxy or polyester resin. That lining exists to prevent the acidic drink from corroding the aluminum wall. It works well for that purpose, but the lining itself is a source of chemical migration into your drink. The most studied of these chemicals is bisphenol A, commonly known as BPA, which has been used in epoxy can coatings for decades.
BPA can migrate from the lining into the beverage under normal storage conditions, not only when cans are heated. It acts as a weak estrogen mimic in the body, binding to estrogen receptors and potentially disrupting hormonal signaling at sufficient doses.1PubMed Central. The Endocrine Disruptor Bisphenol A (BPA) Exerts a Wide Range of Effects in Carcinogenesis and Response to Therapy Animal and cell studies have linked high BPA exposure to metabolic problems including disrupted glucose regulation, early onset of sexual development, and oxidative stress affecting pancreatic function.2Scientific African. Endocrine disrupting effects of bisphenol A exposure and recent advances on its removal by water treatment systems. A review – Section: Effects of BPA exposure The doses required to trigger those effects in animal models tend to be far higher than what a single can delivers, but the concern is about cumulative, long-term exposure from many sources rather than one drink.
How Much BPA Actually Leaches Into Canned Drinks
Measured BPA levels in canned beverages are generally low in absolute terms. One study analyzing migration from beverage cans found BPA concentrations up to about 5,865 nanograms per liter, along with several BPA substitutes including BPF isomers and BPAP. The BPA levels in that study did not exceed specific migration limits set by regulators.3PubMed. The migration of bisphenols from beverage cans and reusable sports bottles That sounds reassuring, but the story gets murkier when you look at newer safety thresholds.
In 2023, the European Food Safety Authority dramatically lowered its tolerable daily intake for BPA, slashing it by a factor of roughly 20,000 from its previous guideline. Under that revised threshold, a broad screening study of commercially available beverages found that BPA exposure from drinking just one average daily portion of a canned beverage could exceed the new safety guideline by up to 2,000-fold. The same study detected 63 different endocrine-disrupting chemicals across the beverages tested, and concentrations were consistently higher in metal cans than in glass, plastic, or carton packaging from the same brands and manufacturers.4PubMed. Exposure to endocrine disrupting chemicals from beverage packaging materials and risk assessment for consumers – Section: Abstract The researchers flagged young children as a group of particular concern, since their lower body weight means each nanogram of BPA represents a proportionally larger dose.
That gap between “within old regulatory limits” and “way over the new guideline” is one of the central tensions in this area. It does not mean every canned drink is poisoning you. It means the science on what constitutes a safe level of BPA is actively shifting, and the direction of that shift has been consistently toward greater caution.
The “BPA-Free” Label Does Not Solve the Problem
Many can manufacturers have moved toward BPA-free linings in response to consumer pressure. The replacement chemicals are typically other bisphenols (BPS, BPF) or various polyester and acrylic coatings. The trouble is that some of these substitutes have shown similar endocrine-disrupting properties in lab studies, and they have been far less thoroughly tested than BPA itself. The screening study that found 63 endocrine disruptors in canned drinks detected not just BPA but also bisphenol structural isomers that had never previously been identified in food products.4PubMed. Exposure to endocrine disrupting chemicals from beverage packaging materials and risk assessment for consumers – Section: Abstract A “BPA-free” label tells you one specific chemical has been removed. It tells you nothing about what replaced it or whether the replacement is safer.
Aluminum Itself Migrates Into the Drink
The interior lining is not a perfect barrier. Over time, aluminum from the can wall dissolves into the beverage, and the rate depends heavily on how acidic the drink is and how long it has been sitting in the can. A study measuring metal content in soft drinks found that fresh cola in small cans contained a mean aluminum level of about 1,510 micrograms per liter. If you drank half a liter daily, that would account for roughly 9% of the tolerable weekly intake for a 60-kilogram person. Herbal soft drinks in cans reached much higher levels, averaging over 7,600 micrograms per liter, though with wide variation between samples. Across all canned beverages tested, aluminum content rose significantly the longer the drinks sat in storage.5Food Packaging and Shelf Life. Metal content in soft drinks depending on packaging and storage time – Section: 3.2.6. Aluminium An older study confirmed the same pattern: more acid in the drink and lower pH meant more aluminum dissolved from the can wall over time.6PubMed. Aluminium content of soft drinks from aluminium cans
How much should that worry you? Aluminum is a known neurotoxicant at high doses, and it accumulates in the body when the kidneys cannot clear it efficiently. The most serious cases of aluminum toxicity have occurred in people with severe kidney impairment, particularly dialysis patients exposed through medical fluids, and in certain occupational settings with chronic inhalation exposure.7ScienceDirect. Handbook on the Toxicology of Metals – Section: Abstract For people with healthy kidneys, the body absorbs less than 1% of ingested aluminum and excretes most of it in urine.8PubMed. Safety evaluation of dietary aluminum So a single can of soda is not going to give you aluminum poisoning. But if you drink several cans a day of highly acidic beverages and those cans have been stored for months, the cumulative aluminum intake adds up in a way that is worth being aware of, especially for people with any degree of kidney disease.
When Cans Are Damaged, the Numbers Get Worse
All of the measurements above assume intact cans with their interior linings in good condition. Dented, scratched, or corroded cans are a different story. Electrochemical corrosion testing on aluminum cans exposed to acidic cola showed aluminum leaching at 0.75 parts per million under mild conditions, which already exceeds the 0.2 milligrams per liter contamination threshold set by the Agency for Toxic Substances and Disease Registry. When corrosion was accelerated, that figure jumped to over 20 parts per million.9PubMed Central. Corrosion Behavior of Aluminium-Coated Cans The practical takeaway: avoid drinking from cans that are visibly dented or damaged, especially around the interior seam. A dent can crack the protective lining and expose the aluminum directly to the acidic beverage.
Microplastics Are in There Too
A newer concern is microplastic contamination in canned beverages. The same polymer lining that protects against aluminum corrosion can itself degrade and shed tiny plastic particles into the drink. A study analyzing carbonated soft drinks from major brands found microplastics in every sample tested, whether packaged in aluminum cans or plastic bottles. Canned beverages contained roughly 150 to 330 microplastic particles per liter, while plastic bottles ranged from about 80 to over 700 particles per liter.10PubMed. High-throughput detection and polymer profiling of microplastics in carbonated soft drinks using laser direct infrared (LDIR) spectroscopy across polyethylene terephthalate and aluminium packaging The types of polymers identified included PET, PVC, polyamide, polyurethane, and PTFE.
The plastic lining inside aluminum cans is one suspected source. The complex sealing mechanisms around the tab and rim may also contribute, since those components can degrade over time.11Heliyon. Assessing microplastic contamination in soda beverages: A Multi-city, Multi-container laser Direct infrared spectroscopy study – Section: Results and discussion The health effects of ingesting microplastics at these concentrations remain uncertain, and this is one of the most active areas of food safety research right now. What is clear is that no packaging format tested so far is free of microplastics entirely.
Heat and Storage Time Make Everything Worse
If there is one practical variable you can control, it is how your canned drinks are stored. Both BPA migration and aluminum dissolution accelerate under specific conditions. Higher temperatures, longer storage, and more acidic beverages all increase chemical leaching. A review of BPA release across packaging types confirmed that temperature and pH are among the most critical factors driving migration, and that exposure to sunlight and prolonged contact time also increase BPA levels in the beverage.12PubMed Central. Bisphenol A release from food and beverage containers – A review Separately, research on elemental migration from cans into food products found that temperature, pH, storage period, and even the specific type of food or beverage all affected how much material leached from the packaging.13Food Control. Leaching of elements from packaging material into canned foods marketed in India – Section: Conclusions
The practical upshot: a can of sparkling water kept refrigerated and consumed within weeks of purchase is a very different exposure scenario from a can of acidic energy drink that has been sitting in a hot car trunk for months. If you store canned beverages, keep them cool and out of direct sunlight. Drink them sooner rather than later. And if a can has been left in a hot environment for an extended period, consider whether it is worth finishing.
The Outside of the Can Is Dirtier Than You Think
Most conversations about canned drink safety focus on what is inside the container. But the outside of the can lid, the part your mouth touches, has its own issues. A study sampling 194 randomly selected cans from homes and retail markets found that about 46% had contamination levels in the “dangerously unsanitary” range, with another 31% in the “cautionary” range. Only about 23% of the cans tested were categorized as clean.14Journal of Food: Microbiology, Safety & Hygiene. Bacteria on Can Lids – Section: Results and Discussion
A separate study examining 180 beverage cans found bacteria on every single one. Bacillus species were present on all samples, and Staphylococcus aureus appeared on over 93% of the cans tested. About a quarter of the cans also carried gram-negative bacteria, including E. coli.15The Journal of Microbiology and Molecular Genetics. Tops of Beverage Cans Are a Potential Source of Infection: A Study of Bacterial Load Present on the Lids of Beverage Cans – Section: Results These are organisms that come from handling, warehouse dust, rodent activity, and general environmental exposure during shipping and storage. The research comparing cans with and without protective plastic covers found substantially lower bacterial counts on covered cans, confirming that the contamination comes from the environment between manufacturing and purchase.16Turkish Journal of Agriculture – Food Science and Technology. Assessment of Hygienic Quality of Beverage Cans Surfaces with and without Protective Cover – Section: Abstract
For most healthy adults, the bacterial loads found on can lids are unlikely to cause serious illness. But for young children, elderly people, or anyone with a weakened immune system, the risk is more meaningful. And the fix is simple.
What You Can Actually Do About It
The most effective way to clean a can lid before drinking is to rinse it under running water and then wipe it with a paper towel. A study evaluating various cleaning methods found that combining rinsing with wiping was significantly more effective at removing bacteria than either method alone. Wiping a dry can without rinsing first was the least effective approach.17Food Service Technology. A microbial survey of food service can openers, food and beverage can tops and cleaning methodology effectiveness Using a straw or pouring the drink into a glass sidesteps the lid contamination issue entirely.
For the chemical migration concerns, the levers you have are limited but real:
- Choose glass when available: studies consistently find lower levels of bisphenols and other endocrine disruptors in glass-packaged beverages compared to cans from the same brands and manufacturers.
- Keep cans cold: refrigeration slows both BPA migration and aluminum dissolution.
- Drink sooner: aluminum and chemical leaching into beverages increase measurably over the shelf life of a canned product.
- Avoid damaged cans: dents and scratches can compromise the interior lining and dramatically increase metal contact with the beverage.
- Be mindful of acidity: highly acidic drinks like colas and energy drinks accelerate leaching more than neutral beverages like water.
Where Regulation Stands
Regulatory agencies worldwide set migration limits for chemicals from food packaging and periodically update them. The gap between the older and newer BPA safety thresholds highlights how much these benchmarks can shift as the science evolves. Currently, agencies recognize that continual monitoring is necessary given how widely canned foods and beverages are consumed.18Food Safety and Health. Canned Foods: Evolution, Benefits, and Health Implications of Modern Packaging – Section: Abstract The U.S. FDA has maintained that BPA is safe at the levels currently found in food packaging, while the European Food Safety Authority has moved toward a far more restrictive position. That transatlantic disagreement is not unusual in food safety regulation, but it does mean that where you live shapes the official reassurance you receive, even though the cans are made the same way.
For consumers, the honest assessment is this: an occasional canned drink is not a meaningful health event for most adults. A daily habit of multiple canned beverages, especially acidic ones stored in warm conditions, stacks up exposure to BPA, aluminum, and other migrants in ways that become harder to dismiss. The science here is not settled, it is moving, and the trend over the past two decades has been to find that lower doses matter more than previously assumed. Paying attention to how you store and handle cans is the most practical response to that uncertainty.
Children and Heavy Consumers Face Different Math
Most safety thresholds are calibrated for an average adult weighing 60 kilograms or more. A five-year-old who weighs 20 kilograms receives three times the per-kilogram dose from the same can. The screening study that flagged BPA exposure up to 2,000-fold above the revised European guideline specifically called out young children as a population of concern.4PubMed. Exposure to endocrine disrupting chemicals from beverage packaging materials and risk assessment for consumers – Section: Abstract Kidney function also matters. Since aluminum is cleared primarily through the kidneys, anyone with reduced kidney function clears it more slowly and accumulates it more readily.7ScienceDirect. Handbook on the Toxicology of Metals – Section: Abstract For people in these categories, limiting canned beverage consumption or switching to glass is a more directly consequential decision than it is for a healthy adult who has a can of seltzer a few times a week.