Actually spinach is a food with one of the highest level of oxalic acid. It is a problem because it binds with calcium and interferes with absorption. It's also implicated in kidney stones. Cooking may reduce the level somewhat.
Also, the iron in spinach is a nonheme iron so spinach is not a good source of *usable* iron. Other foods, e.g., oysters, chicken livers, will give you better iron that your body can use. Not spinach.
One of the few thing I eat that I think is good for me and I like and you have to go and muck it all up! Please don’t tell me Brussels sprouts are poisonous.
Well you see the truth is a mushy middle....spinach in the presence of other foods seems to inhibit what the oxalic acid does and allows the absorption of more of spinach’s iron. I always heard spinach alone is not so good, but spinach with other foods allows its full benefits to be released to the body. Other types of “soul food greens”...not so much!