How to improve iron absorption in a patient with anemia and low ferritin levels due to hepcidin interference, when intravenous (IV) iron is unavailable?

Optimizing Iron Absorption in a Patient with Hashimoto's Flareup and Low Ferritin

For patients with Hashimoto's thyroiditis experiencing anemia with low ferritin and hepcidin interference, taking oral iron on alternate days with vitamin C in the morning is the most effective strategy when IV iron is unavailable. 1, 2

Understanding the Problem

• Hashimoto's thyroiditis involves inflammation that increases hepcidin levels, which blocks iron absorption from the gut and iron release from storage sites 1
• Low ferritin (<60) despite some improvement indicates ongoing iron deficiency 1
• Hepcidin interference is a key factor limiting iron absorption in inflammatory conditions 1

Optimizing Oral Iron Absorption

Dosing Strategy

• Alternate-day dosing is superior to daily dosing - Studies show that taking iron every other day results in higher fractional iron absorption (21.8% vs 16.3%) and higher total iron absorption (175.3mg vs 131.0mg) 2, 3
• This occurs because daily iron dosing stimulates hepcidin for up to 24 hours, blocking absorption of subsequent doses 2, 3
• Morning single dose is better than divided doses - Taking the full dose in the morning rather than splitting throughout the day prevents the circadian increase in hepcidin that would reduce afternoon/evening absorption 2, 3

Dose Recommendation

• Use 60-120mg of elemental iron as a ferrous salt (ferrous sulfate, fumarate, or gluconate) 1
• Ferrous sulfate (65mg elemental iron per tablet) is a reasonable first choice due to cost-effectiveness 1
• Higher doses (up to 120mg) may be needed with significant inflammation but can increase side effects 2

Enhancing Absorption

• Take with vitamin C (ascorbic acid) - 500mg of vitamin C taken with iron forms a chelate that prevents formation of insoluble iron compounds and reduces ferric to ferrous iron 1
• Take iron on an empty stomach for optimal absorption 1
• Avoid tea and coffee within 1 hour of taking iron as they are powerful inhibitors of iron absorption 1
• Consider taking iron with meat protein if tolerated, as this improves absorption 1

Monitoring and Adjustments

• Expect hemoglobin to increase by 1 g/dL within 2 weeks if absorption is adequate 1
• Ferritin should show measurable increase within one month 1
• If no improvement after 4-8 weeks despite adherence, consider:
  • Increasing the dose (up to 120mg elemental iron) 2
  • Adding additional vitamin C (up to 500mg) 1
  • Exploring IV iron options again as this would be more effective with inflammatory conditions 1, 4

Common Pitfalls and Caveats

• Don't take iron with calcium or fiber - These substances inhibit iron absorption 1
• Avoid taking iron with thyroid medication - Space these medications at least 4 hours apart to prevent interference
• Don't consume tea/coffee within 1 hour of iron supplementation 1
• Don't take iron more than once daily - This increases side effects without improving absorption due to hepcidin response 1, 2
• Don't continue ineffective oral therapy indefinitely - If no response after 8 weeks of optimized oral therapy, IV iron should be reconsidered as it bypasses the gut absorption issues 1, 4

Special Considerations for Hashimoto's

• Optimize thyroid function as hypothyroidism itself can contribute to anemia 1
• Consider anti-inflammatory dietary approaches that may help reduce hepcidin levels
• Monitor both iron parameters and thyroid function regularly, as improvements in thyroid function may help improve iron absorption 1

If oral iron remains ineffective despite these optimizations, IV iron would be the most appropriate next step, as it bypasses the gut absorption issues caused by hepcidin interference 1, 4, 5.