If the food is slightly acidic though wouldn't that leech metals into your food?

Acidic foods went in glass containers. I have old books on food preservation, and they talk about which foods can't be stored in metal cans, which must be pickled (or later pressure canned) to prevent botulism, and so on. There used to be a lot of knowledge involved in storing and preserving food, because the method had to be suited to the food in question.

That's why canned acidic foods are some worse offenders when it comes to leeching stuff.

There's a plastic lining in the metal cans now.