Is it safe to take vitamin C with ferrous sulfate (iron supplement)?

Taking Vitamin C with Ferrous Sulfate

Taking vitamin C with ferrous sulfate is not only safe but beneficial for iron absorption, with 500 mg of vitamin C recommended to enhance iron absorption even when taken with meals containing calcium or fiber. 1

Benefits of Combining Vitamin C with Iron

• Vitamin C (ascorbic acid) improves iron absorption through several mechanisms:

  • Forms a chelate with iron that prevents formation of insoluble iron compounds
  • Reduces ferric iron to the more absorbable ferrous form
  • Allows iron absorption even when calcium or fiber is present in meals 1

• The American Gastroenterological Association (AGA) specifically recommends taking iron with 500 mg of vitamin C to improve absorption 1

• For patients who cannot tolerate iron on an empty stomach, taking it with vitamin C can help maintain absorption even when taken with food 1, 2

Optimal Administration

• For maximum absorption:

  • Take iron supplements on an empty stomach when possible
  • If taking with food (to reduce GI side effects), add vitamin C
  • Avoid taking iron with tea or coffee, which inhibit absorption (wait at least one hour after consuming these beverages) 1, 2
  • Taking iron with meat protein also improves absorption 1

• Dosing frequency:

  • Once-daily dosing is recommended over divided doses
  • Taking iron more than once daily does not improve absorption but increases side effects 1
  • Some evidence suggests alternate-day dosing may improve tolerance 1

Special Considerations and Cautions

• For most people with iron deficiency, vitamin C supplementation with iron is beneficial and safe 3

• Important exception: In patients with hemochromatosis or iron overload conditions:

  • Vitamin C supplementation should be avoided, especially before iron depletion 1
  • High-dose vitamin C can accelerate iron deposition in tissues and potentially worsen cardiac function in severe hemochromatosis 1
  • If supplementation is necessary in these patients, it should be limited to 500 mg daily and discussed with a physician 1

Managing Side Effects

• Common side effects of ferrous sulfate include:

  • Constipation (12% of patients)
  • Diarrhea (8% of patients)
  • Nausea (11% of patients) 1, 2

• If side effects occur:

  • Taking iron with food may reduce GI irritation (though this reduces absorption by up to 50%)
  • Adding vitamin C can help maintain absorption even when taken with food
  • Consider alternative iron formulations if side effects persist (ferrous fumarate or gluconate) 2

Effectiveness of Combined Therapy

• While vitamin C enhances iron absorption, the overall clinical benefit of routine vitamin C co-administration on hemoglobin or ferritin levels remains somewhat mixed in research studies 4

• However, current clinical guidelines continue to recommend vitamin C supplementation with iron based on established physiological mechanisms and clinical experience 1, 2

In conclusion, taking vitamin C with ferrous sulfate is a recommended practice that enhances iron absorption and may improve treatment outcomes for iron deficiency anemia. The only major contraindication is in patients with hemochromatosis or other iron overload conditions.