Nevertheless, most glazes have a much more complex composition than the standard borosilicate or soda-lime glasses.
Glazes usually contain colorants and various additives that improve certain properties useful during manufacturing, which do not exist in the glasses used for vessels.
It is possible to make glazes that are perfectly safe for food contact, but historically there were many examples of glazes with harmful components.
Unless a manufacturer provides the composition of the glaze used by them, you cannot know how safe it is.
Moreover, glazes and enamels have a problem that does not exist for stainless steel vessels. The glazes or enamels may crack and expose the base material to the food. However that is somewhat mitigated by their lower price, which facilitates the replacement of the cookware.
Or you could just buy from any EU country:
https://www.european-enamel-association.eu/certification.htm...
> 4.8 Specification and determination of the release of toxic elements
> The specification and determination of the release of toxic elements must comply with the requirements specified in the national laws of the country.
Most of the other requirements are about the mechanical properties of the enamel.
There's also this:
> 4.32 Determination and control of Lead and Cadmium release for hot water tanks
But that doesn't apply to cookware.
There's nothing here about requirements for the composition of the enamel or the making public thereof. And what constitutes a "toxic element" (and presumably the dosage) is left to the laws of each country. Most of these countries would consider stainless steel to meet their leeching requirements as well. So we're back to square one. There's no way to tell what the enamel is leeching. You just have an assurance that it's considered safe.
So we consider stainless steel pans as food safe generally, yet they do leach something. I don't see how food safe could imply that something doesn't leach. Only that we either think it doesn't leach too much or we don't think what it leaches is harmful.
This is why I specified "buy from a reputable manufacturer" because there is no risk of this whatsoever if you get contemporary / new cookware from the indicated regions; that list isn't exhaustive but I stand by this: any cookware you buy new from EU, America, or Japan, will not contain lead in the glaze, or anything else you wouldn't want to eat very small amounts of.
Has this been verified in practice? Is enamel always pure, or can it contain contaminants that can leach?
Enameled pans aren't going to leach anything if you buy them from any reputable manufacturer (which is at least all of the European, American, and Japanese ones) because any colorants added to the glaze will be rated as food safe. In fact, you mentioned titanium: that's what's used to make the inside of white enameled pots look white.
Enameled cast iron (or enameled anything) is a fine choice, it comes with its own limitations culinarily (and advantages) but it isn't going leach anything into your food.