Are Vitamin C Supplements Essential for Treatment of Iron Deficiency Anemia?

A regimen of oral iron supplements alone was found to be comparable to oral iron plus vitamin C supplements in improving hemoglobin recovery and iron absorption in patients with iron deficiency anemia (IDA).

Researchers from Fudan University in Shanghai, China, conducted a randomized clinical trial of 440 adults with newly diagnosed IDA. Participants were randomized 1:1 to either 100 mg oral iron supplements plus 200 mg vitamin C or 100 mg oral iron alone. The regimens were taken every 8 hours daily for 3 months. The study’s primary outcome was change in hemoglobin level from baseline at 2 weeks of treatment, with a predetermined equivalence margin of 1 g/dL in hemoglobin selected for comparable efficacy.

After 2 weeks, the mean change in hemoglobin level was 2.00 g/dL in the iron plus vitamin C group, compared with 1.84 g/dL in the iron only group (between-group difference, 0.16 g/dL; 95% CI −0.03-0.35 g/dL). The difference met prespecified criteria for equivalence. There were no significant differences between the two groups regarding the rate of adverse events.

“The findings of this equivalence RCT demonstrate that in patients with IDA, taking oral iron alone was equivalent to taking oral iron supplemented with vitamin C in improving hemoglobin level and iron stores. Our results suggest that vitamin C is not essential for patients with IDA,” the researchers concluded.

Results from this study were published in JAMA Network Open.