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Comment by badc0ffee | Hacker News Reader

It's non-toxic and food safe, and yet a significant number of people on the internet still act like it's poison that will give you Alzheimer's. I wonder how many of those people touch their lips to the lid of an aluminum beverage can. Or how they might bake a lasagna at home.

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You shouldn't use aluminum foil with tomato/lemon/vinegar/brined foods or as "grilling packets" (direct fire/high heat) because of leaching risk.

There's no concern with using aluminum in most cases (with dry/non-acidic foods) but leaching is a real problem with acidic/salty/wet/high eat.

I put aluminium foil over a bowl of pizza dough, as it grew the top touched the foil and in a few spots tiny holes appeared in the foil. I wonder if it was carbonic acid or what

It probably formed a weak battery electrode with the bowl and electro-deposited it on the substrate (pizza). Happens often with tomato sauces, like lasagnas.

Oh, thanks! You are surely correct; I was puzzled about how something as relatively inert as pizza dough could corrode aluminum at multiple microns per hour, but electrolysis can definitely do that.

What is the leaching risk, though? If aluminum does get in your food, is it bad for you in a specific way, or is it more like iron?

Aluminum is generally thought to be benign by most authorities.

However, it is worth noting that humans were not exposed to aluminum in the environment until relatively recently, when we started extracting it from bauxite and melting it.

Pure aluminium maybe not, but it's a major component of clay.

Aluminum is a major component of all soils, and soluble aluminum salts have been used in medicine and dyeing since ancient Greece, probably since ancient Egypt. They have been used in food preparation for at least several centuries.

These are all separate chemical compounds, though. Are you claiming they all behave the same as refined aluminium?

I'll readily sprinkle soluble sodium chloride salt over my food. I still very much prefer to keep both substances away from it in elemental form.

Note that I'm not claiming aluminium were dangerous, just that your argument is deeply flawed.

It's not that my argument is flawed so much as that it depends on some basic background knowledge about processes like corrosion and solvation. Lacking that knowledge, you're better off taking my word for it that humans are not exposed to aluminum in the environment in a different way since we started refining the metal.

Like most metals, excess aluminum in your diet is almost certainly bad for you.

EFSA full review: animal studies show nervous-system effects from aluminum exposure. https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa....

CDC/ATSDR: oral risk levels are based on neurological effects seen in exposed animals. https://wwwn.cdc.gov/TSP/ToxProfiles/ToxProfiles.aspx?id=191...

Let's see if this is a quantitatively plausible concern.

https://en.wikipedia.org/wiki/Aluminium_chloride says orl-rat LD₅₀ of AlCl₃ is 380mg/kg, which is 20.2% aluminum by weight, so that's 77mg/kg of soluble aluminum ions. If this toxicity is due to soluble aluminum ions (rather than, say, acidity), and rats and humans are about equally sensitive to aluminum toxicity, you'd need about 3.8g of aluminum to kill a 50kg human, the ionized equivalent of 1.42mℓ of aluminum metal (at 2.71g/cc). That's 1420cm² of 10μm aluminum foil completely dissolved in the food.

Presumably you would get significant toxic effects well before reaching the lethal dose, so it would be wise to avoid exposures larger than a few tens of cm² of aluminum foil completely dissolved in your food. So it seems like the concern at least passes the first smoke test of plausibility: the total amount of aluminum present in a "grilling packet" is at least sufficient to worry about.

(Fortunately, aluminum rapidly becomes inert in the body, so we don't have to be concerned about gradual poisoning the way we do with lead and arsenic.)

The crucial question, then, is how fast the foil corrodes under cooking conditions! If it corrodes (and migrates into the food) at a micron or more per hour, then this could be a serious concern. But, if the corrosion rate is more like microns per month or microns per year, the dose wouldn't be high enough to worry about.

The fact that https://en.wikipedia.org/wiki/Aluminium_toxicity redirects to https://en.wikipedia.org/wiki/Aluminium_toxicity_in_people_o... suggests that this is at least not a recognized concern.

How long does it take to leave the body?

I'm not sure, but I think that normally it reacts with phosphate ions to form aluminum phosphate rather than leaving the body.

There's no risk to leeching, there's no data proving any link at all between Aluminum and Alzheimer's. I was a huge advocate for staying away from Aluminum cooking stuff for a long time and my mother even wound up with Alzheimer's. Simply put, I was wrong, there's no link.

> "There's no risk to leeching, there's no data proving any link at all between Aluminum and Alzheimer's."

EFSA (European Food Safety Authority) says acidic or salty foods can increase aluminum leaching from pans and foil into food: https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa....

This review found mixed evidence and a positive meta-analysis signal for aluminum exposure and Alzheimer's: https://www.sciencedirect.com/science/article/pii/S014765132...

It's not that hard to avoid this leaching concern, seems smart to make a basic effort to do so.

"Aluminum (Al) is a widespread environmental contaminant " - they lost me right there in the very first sentence.

Already using charged, non-neutral language ("contaminant"), giving away their pre-existing bias and forcing me to disregard the rest of their opinion on the matter. Aluminum is no more "environmental contaminant" than any other extremely common basic element in the Earth's crust, like silicon or iron. Are they also against chlorine?

Clearly they decided to conduct a study to show just how scary aluminum is, and I have no doubt the succeeded.

Yeah, it's the third most abundant element on the planet. If that's a contaminant, then so is iron and oxygen and nitrogen. Did you know Dihydrogen Monoxide is found in 100% of cancers?

This is a paper on ecotoxicology and environmental safety, so describing aluminum as an "environmental contaminant" makes sense in this context.

> "Did you know Dihydrogen Monoxide is found in 100% of cancers?"

Did you know humans intentionally consume water because they need it to survive, and do not intentionally consume aluminum?

The EU is known to be far more conservative with health and safety than other areas. I focused on the risk of aluminum, not leeching because leeching doesn't matter of the aluminum doesn't cause any issues. And from what I'ce seen in the past decade, it doesn't. I was wrong.

i heard aluminum food containers are often coated with toxic liners, like plastics, bpa, and pfas. If Alzheimers isnt a risk with pure aluminum metal, id say those liners are a huge risk. Are kitchen foils coated? Im pretty sure cans are most of the time.

"Plastic" in general isn't toxic as a liner. It's used in plumbing, and in zillions of containers for potable water and foods. When you get food from even a nice restaurant, they probably marinate meat in a plastic container, and squeeze fruit juice into a plastic container. They sous vide items in plastic.

I've also never heard of a plastic/Alzheimer's connection, only one claimed with aluminum.

i didnt mean those contaminents cause Alzheimers, just that its a risk to general health. food grade plastic is not considered toxic at these doses, but u def dont want it in your body if u can avoid it within reasonable effort. i use freezer bags made from plastic , and reuse plastic ziplocs from some food stuffs i buy to marinate meat, its really convenient to be able to remove the air and have the marinade fully coat the food. i reuse plastic water bottles until i forget them somewhere. im def using plastic to store food. i eat canned food too, and most of the cans mention something about their liner safety right on the can. bpa-ni is interesting, in that they say they dont intentionally use bpa liner, but bpa could still be there, wtf , how are u so unsure as a manufacturer to what ur inputs are on a factory made can. that being said, im not storing food in there for years, only hours when i use plastic in my own processes. plastic in can liners often holds food for years, and the expiration date of canned food is often many years after the food is manufactured and canned.

"Plastic" is not a material; it's a property or state of many unrelated materials. It doesn't make any more sense to say that plastic is a risk to health than to say that liquid is a risk to health or that crystals are a risk to health.

I've only seen people concerned with it in antiperspirants, where it's a salt. (And to be clear, I think it's BS.)

As with NaCl, it's at least possible that the salt and the pure-ish variant aren't quite the same thing.

Probably not complete BS. This is anecdotal, but years of experience has taught me that aluminum-containing antiperspirants cause contact dermatitis for me after extended use.

I was also diagnosed with a nickel allergy by a dermatologist when I was a child. Metal allergies are real.

I wouldn't go so far as to say aluminum is toxic for everyone, but it's certainly something I avoid putting on my skin.

how funny things work - from Napoleon serving his special guests on aluminium utensils [1] to everyone taking it for granted, even treating it as if it is toxic!

cost and availability somehow has a negative correlation to how we treat something.

[1] https://en.wikipedia.org/wiki/History_of_aluminium#Early_ind...

Romans used lead utensils, I don't think that was due to cost.

we used to believe lead could be turned into gold, and used it in fuel to paint not too long ago.

hindsight 20/20, maybe i will be proven ignorant about aluminium in the future.

That aluminum beverage can (and also tin cans) is lined with a kind of plastic, so you and food aren’t in contact with the actual aluminum in that case

But the top of the lid is unlined, I think.

Nothing against aluminum foil here, but we make lasagna at home all the time in a square ceramic baking dish.

I will not give up my Jiffy Pop when camping!

1) all of them

2) glass dish

I use a glass/Pyrex dish, but put foil on top. I guess you could use a fitted glass lid instead, depending on the container.

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