Final answer:
On average, women lose about 1 milligram of iron per day due to menstruation, which can typically be balanced through diet unless there is excessive blood loss or anemia requiring supplements.
Step-by-step explanation:
Menstrual losses vary considerably, but over a month, they average about 1 milligram per day for women. In adult women, the average loss of iron with blood during the menstrual period is 16-32 mg per month, which when divided across the average menstrual cycle length equates to an additional loss of about 0.5 to 1.0 mg per day. This amount is generally compensated for through dietary intake. However, during times of excessive menstrual blood loss or in chronic iron-deficiency anemia, a higher daily supplemental intake of iron may be required.