 Over the last decades, the toxicity of aluminum for humans has been heavily discussed and still not completely clarified. Those occupationally exposed to aluminum and smelter plants suffer from oxidative stress, free radicals that can damage their DNA. But what about just using aluminum cookware? Articles like this, suggesting an unrecognized public health risk, was limited to the developing world, where cookware is made in informal shops by casting liquid aluminum melted from a collection of scrap metal, including the likes of lead batteries, which is how you can get so much lead leaching into people's food. But then this study was published, suggesting the aluminum itself may be harmful. Most of our aluminum exposure comes from processed junk. That contains aluminum-containing food additives, including those within some processed cheeses, baking powders, cake mixes, frozen dough, and pancake mixes. But approximately 20% of the daily intake of aluminum may come from aluminum cooking utensils, such as pans, pots, kettles, and trays. To see if this may be causing a problem, they took blood from consumers that used aluminum cookware versus those that did not, and found that not only were the aluminum users walking around with twice the level of aluminum in their blood, but they had more free radical damage of their body fats and proteins, and the total antioxidant capacity of their bloodstream was compromised. So no surprise suffered significantly more DNA damage. And indeed, those with the highest levels of aluminum in their blood tended to suffer significantly more damage to their DNA. No surprise, since aluminum is considered to be a pro-oxidant agent. These folks weren't just casually using aluminum pots, though, but specifically using them daily to cook and store acidic foods like yogurt and tomato sauce, which can leach out more aluminum. But even just a week using like camping dishes, which tend to be aluminum since they're so light, if you were incorporating something acidic like marinating a fresh catch in lemon juice, could greatly exceed the tolerable weekly intake guidelines, especially for children. Once in a while it's not going to make much of a difference, but this suggests that you may not want to be cooking an aluminum day in and day out. What about aluminum drinking bottles? They're nice and light, but children drinking two cups of tea or juice a day from them could exceed the tolerable aluminum exposure limit. So out of an abundance of caution, safety authorities, like the German Federal Institute for Risk Assessment, recommend that consumers avoid the use of aluminum pots or dishes for acidic or salted foodstuffs, such as applesauce, rhubarb, tomato puree, or salt herring to avoid any unnecessary ingestion of aluminum. What about aluminum foil? It's a common culinary practice to wrap food in aluminum foil and bake it. The concern is that this could potentially present a hazardous source of aluminum in the human diet. When put to the test, yes there was leakage from the foil to the food, but the amount was so small that it would be more of an issue for small children or those suffering from diminished kidney function. What about just wrapping a food in foil to store in the fridge? Only marginal increases in aluminum are seen, unless the food is in contact with both the foil and at the same time certain other types of metal. For example, stainless steel, which is largely iron, and so that sets up a battery and so can lead to tremendous food aluminum concentrations. For example, here's the aluminum levels in a ham. Before and after a day covered in foil. But take that same ham and that same day of foil on top of a steel tray or serving plate, and the aluminum levels in the ham shoots up. And finally, you know how there's sometimes a glossy side of aluminum foil and then kind of a dull side? Which would be worse? Fish fillets were baked and grilled both ways, wrapped in the glossy side versus wrapped in the dull side, and no significant difference was found.