Slide 1: You’ve just diagnosed one of your patients with iron-deficiency anemia. How do you advise them to take their ferrous sulfate? A) First thing in the morning. B) Once every other day. C) With their daily omeprazole. D) With a glass of fresh-squeezed orange juice.

Slide 2: Two right answers! B) Once every other day and D) with a glass of fresh-squeezed orange juice.

Slide 3: Ascorbic acid (or vitamin C) reduces ferric sulfate (3+) to ferrous sulfate (2+), which is more easily transported into the intestinal enterocyte. To that end, it has been suggested that a concomitant dose of vitamin C may enhance the bioavailability of oral iron supplements! (Similarly – it’s not a good idea to mix ferrous sulfate with PPIs or anti-acids, which diminish the stomach’s acidic content, keeping the supplemented iron in its less readily-absorbed ferric form!)

Slide 4: The timing of the dose matters, too! Research suggest that the frequency of iron supplementation can impact hepcidin production (recall: hepcidin binds to transport channels on the enterocyte, impeding intestinal uptake of iron). In one randomized controlled trial from 2017, daily scheduled iron led to higher levels of hepcidin (and thus less absorption) when compared to alternate-day dosing.


  • Zimmermann MB, Hurrell RF. Nutritional iron deficiency. Lancet. 2007 Aug 11;370(9586):511-20. PMID 17693180
  • Moretti D, Goede JS, Zeder C, et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. Blood. 2015 Oct 22;126(17):1981-9. Epub 2015 Aug 19. PMID 26289639

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