[EnderViaAnsible]

The translation of deficiencies into food cravings has always fascinated me. People with pica, for example, often compulsively eat non-foods that are in fact related to a deficiency they have. Anemics sometimes crave dirt (which does contain iron).

But how does it "know"?

[wccrawford]

I don't think your body "knows". I think your mind is very, very good at pattern recognition. It knows that when certain signals exist, a certain condition exists, and when certain foods are eaten, those signals are lessened. It doesn't know what foods will do what until after you've eaten them, possibly multiple times.

[s_y_n_t_a_x]

Probably a memory of the taste and the vitamins that follow it.

My wife craves mints when she's low on iron.

[samstave]

But do mints provide any iron?

[bjoli]

If they are fortified they do, or better up if they are some kind of mint-flavoured supplements.

[s_y_n_t_a_x]

Depends on which kinds. Spearmint can contain up to 15% of your DV of iron.