Efficacy of vitamin C with Fe supplementation in patients with iron deficiency anemia: a systematic review and meta-analysis
Joanna Deng, Luca Ramelli, Pei Ye Li, Ali Eshaghpour, Allen Li, Giovanna Elsa Ute Muti Schuenemann, Mark Crowther
Abstract
Oral iron (Fe) supplementation is one of the mainstays of treatment for iron deficiency anemia (IDA). However, its therapeutic effects are limited when there is poor absorption from the gastrointestinal tract. Vitamin C is hypothesized to improve uptake when combined as an adjunct agent. We aimed to determine the difference in hematological outcomes in IDA patients receiving oral iron, with or without vitamin C. MEDLINE, EMBASE, Web of Science and CENTRAL were searched from database inception to July 2023 for studies investigating the use of oral iron supplements with vitamin C in IDA patients. The primary outcome was the change in serum hemoglobin. Secondary outcomes include change in serum ferritin, reticulocyte percentage, and incidence of adverse events. 2231 studies were retrieved - 10 RCTs (n=1782) and one prospective cohort study (n=148) comprising 1930 patients were included. Vitamin C supplementation was associated with a significant increase in serum hemoglobin level (MD 0.14 g/dL [95%CI 0.08, 0.20], p<0.01,10 studies, 1490 patients) and serum ferritin levels (MD 3.23 μg/L [95%CI 1.63, 4.84], p<0.01, 9 studies, 1682 patients) in the iron + vitamin C group compared to the iron only group. The addition of vitamin C to iron supplementation was associated with a small and likely clinically insignificant increase in serum hemoglobin. The results of this study do not support routine supplementation of oral iron therapy with vitamin C in the treatment of IDA.