Of course a coach shouldn’t be dispensing medical advice and this should all be done under the supervision of a physician. But the coach can recommend the athlete go to a doctor, preferably one familiar with distance running, and get an iron panel done w serum ferritin. The “normal” range is wide, like 15-250 or something, different for men and women.
A lot of doctors think 15 is normal and ok, but it’s just simply not. 50 should be the target. Minimally 30. We are not talking about athletes trying to get it to 200 here, just maintain adequate iron storage levels. And, yes, diet and rest help.