Any kind of iron cookware leaches in food a quantity of iron that is many orders of magnitude greater than all metals leached by stainless steel.

Fortunately, excessive quantities of iron in food are not dangerous for most people, even when the quantity is great enough to give an unpleasant taste to the cooked food.

In any case, iron cookware is preferable to ceramic/plastic/non-sticking cookware of unknown chemical composition.

About enamel, that is a complex mixture of various oxides.

All colored enamels have undesirable components.

White enamel can be made perfectly safe for food contact. Unfortunately, being white is not a guarantee for that.

Manufacturers are tempted to include in the enamel composition various oxides that improve the manufacturing properties, e.g. which increase the fluidity of the melted enamel, or which enhance the adherence of the enamel to the base metal, and so on. These additives may leach unwanted substances.

So one may use cookware with white enamel, if they trust that the manufacturer was not too greedy to reduce their costs.

Ideally there should be a law to force all manufacturers of cookware to publish the precise chemical composition of any material used for food contact, like there are laws for labels with the approximate food composition.

Until then, it is safer to distrust any kind of coatings, plastics, enamels or glazes with secret compositions, because in the past there were many bad surprises whenever any of these were analyzed.

I like the way you think. If you have a pan made of food, does it matter if some food leaches to your food? For a person with iron deficiencies it's hard to argue additional iron is bad, however...

Once your iron gets into contact with oxygen, you will no longer consume iron, you will consume rust...

Solution: don't use "unsafe" Rust.

Oh stop you.

ah ah ah !

Actually what you need in your body is rust, i.e. iron ions.

Metallic iron cannot be used in any way by living beings, before it is oxidized to rust.

The leaked iron from cookware is already in the form of "rust", more precisely the iron is leached after it is oxidized to iron ions. The ions with 2 elementary charges remain dissolved in the water, and they may be absorbed by the body, while the iron ions with 3 elementary charges (these are the components of rust in the strict sense, i.e. of red iron oxide) will normally precipitate into red rust crystals, which will pass through the digestive tract mostly without being absorbed (a few might be reduced to ions with 2 charges, and then be absorbed).

I am not an expert but it seems that the form of iron absorbed by human body is ferrous sulfate, iron in +2 oxidation state. Iron rust of iron pan is in +3 state, which is chemically a different thing.

Your comment reminds me of the Lucky Iron Fish[0] developed in Cambodia as an iron supplement for populations plagued by iron-deficient anemia.

[0] https://en.wikipedia.org/wiki/Lucky_iron_fish

You beat me to this!

https://www.bbc.co.uk/news/health-32749629

You can buy them in the west now (even on Amazon I think):

https://luckyironfish.com/

I think a lot of the iron in the body is already in ionic form, so it's not a huge concern.

The issue with iron cookware (and I'm a big fan) is cooking acidic dishes in them (which are the ones that mainly cause the leeching) you destroy the seasoning and they become a bit of a pain to clean after that.

Iron pans are not the best for those with hemochromatosis (iron overload).

Is iron cookware really just iron, or is it alloyed slightly?

A little bit of carbon (2-4%) and silicon. Otherwise it's just iron.

It should also be noted that with a properly seasoned cast iron pan, the food isn't interacting as much directly with the iron, since the seasoning layer (polymerized fats) is in the way.