Iron Deficiency Anemia Treatment with Ferrous Fumarate and Vitamin C

Dosing Recommendations

The American Gastroenterological Association recommends taking 210 mg ferrous fumarate once or twice daily (depending on menstrual status) with vitamin C to enhance absorption, separating it from calcium supplements by 1-2 hours, for patients with iron deficiency anemia 1, 2, 3
Non-menstruating adults should take 210 mg ferrous fumarate once daily, while menstruating women should take 210 mg ferrous fumarate twice daily (providing 50-100 mg elemental iron daily) 1, 2, 3
Iron supplementation should be continued for 3 months after correction of iron deficiency to replenish stores, as recommended by the British Society of Gastroenterology 4

The American Gastroenterological Association recommends adding vitamin C as a Best Practice Advice, recognizing it as the most potent enhancer of non-heme iron absorption, with practical options including taking iron with orange juice or 250-500 mg ascorbic acid 5
Vitamin C is particularly critical for plant-based diets where non-heme iron predominates, and should be taken with iron to enhance absorption 5

Iron should be taken once daily in the morning when hepcidin levels (which inhibit iron absorption) are lowest, or consider every-other-day dosing as an alternative, which may be equally effective with better tolerability 5
Iron should be taken on an empty stomach for maximum absorption, though this must be balanced against tolerability, and separated from calcium by 1-2 hours as calcium inhibits iron absorption 1, 2, 3

If gastrointestinal side effects are intolerable, take iron with small amounts of food (accepting reduced absorption for improved adherence), start with lower doses and gradually increase to target, or try taking iron at bedtime 5, 6
Consider alternative formulations like ferrous gluconate or iron bisglycinate if side effects persist, as recommended by the British Society of Gastroenterology 4, 5, 6

Patients with hemochromatosis or iron overload must completely avoid vitamin C supplements, as vitamin C accelerates iron mobilization and can cause cardiac complications including sudden death, and if vitamin C is required for other medical reasons in iron-loaded patients, limit to 500 mg daily only after physician discussion 5

Recheck hemoglobin and ferritin levels to assess response to iron supplementation, and adjust supplementation based on blood results, as recommended by the British Society of Gastroenterology 1, 4