What does low iron mean?

Low iron usually means iron-deficiency anemia developing or established: iron is the raw material of hemoglobin, the oxygen-carrying protein in red blood cells, so without enough iron your blood carries less oxygen - and the symptoms are the sound of that shortfall: fatigue, pale skin, breathlessness on stairs, cold hands, brittle nails, sometimes restless legs or strange cravings for ice. MedlinePlus's iron-tests page explains the measurement: ferritin (your iron stores) falls first, before the blood count itself drops - so a low ferritin with a normal hemoglobin is the early warning. The number is never the whole answer, because low iron is a sign, not a diagnosis: the question is why. The three usual explanations: not enough in (vegetarian diets without planning, poor intake generally), too much out (heavy menstrual periods are the commonest cause in young women; slow gut blood loss - from ulcers, polyps, or worse - is the cause nobody must miss, especially in men and older adults), and poor absorption (celiac disease, bariatric surgery, some medications). The fix follows the cause: iron-rich food (red meat, beans, greens - with vitamin C helping absorption, tea and coffee hindering it), supplements when food is not enough (they take weeks to months and can constipate), and always the investigation of 'why' when the cause is not obvious. Pymander is a free AI doctor, 24/7 by text, that can help you think through your result.