From the Guidelines
The recommended dosage of vitamin C to enhance iron absorption when taking iron supplements is 80 mg, taken at the same time as the iron supplement, as it has been shown to improve iron absorption in a recent iron isotope study 1.
Key Considerations
- Vitamin C improves absorption by forming a chelate with iron that prevents the formation of insoluble iron compounds and by reducing ferric to ferrous iron 1.
- Taking iron with vitamin C on an empty stomach can further enhance absorption 1.
- It is also important to note that tea and coffee are powerful inhibitors of iron absorption and should not be consumed within an hour after taking iron 1.
Additional Recommendations
- Individuals should avoid consuming calcium-rich foods, tea, coffee, or dairy products within two hours of taking iron supplements, as these can inhibit iron absorption 1.
- Consider advising people to take iron supplements with citrus fruits/drinks or vitamin C to enhance absorption 1.
Evidence Summary
The evidence supporting the use of vitamin C to enhance iron absorption is based on a recent iron isotope study that showed taking iron with 80 mg ascorbic acid on an empty stomach improves iron absorption 1. While the evidence is not yet conclusive, and further study is needed to clarify the effectiveness of this practice 1, the available data suggest that vitamin C can play a beneficial role in enhancing iron absorption.
From the FDA Drug Label
Directions Adults and Children 12 years and over: 500 mg (1 tablet) daily or as directed by your doctor The recommended dosage of vitamin C to enhance iron absorption is not explicitly stated in the provided drug label. However, the label suggests a daily dose of 500 mg for adults and children over 12 years old.
- The label does not provide information on the specific dosage for enhancing iron absorption.
- It is essential to consult a doctor for specific guidance on taking vitamin C with iron supplements 2.
From the Research
Vitamin C Dosage with Iron
- The recommended dosage of vitamin C to enhance iron absorption in individuals taking iron supplements is not explicitly stated in the provided studies.
- However, a study published in 2020 3 suggests that providing morning doses of 60-120 mg iron as a ferrous salt given with ascorbic acid on alternate days may be an optimal oral dosing regimen for women with iron-deficiency and mild IDA.
- Another study published in 2023 4 found that the pooled estimate for standardized mean difference of hemoglobin and Serum Ferritin for intervention type 'oral iron and vitamin C' was not statistically significant.
- A study published in 2017 5 compared iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women, but did not specify the optimal dosage of vitamin C.
- A randomized clinical trial published in 2020 6 found that oral iron supplements alone were equivalent to oral iron supplements plus vitamin C in improving hemoglobin recovery and iron absorption, suggesting that on-demand vitamin C supplements are not essential to take along with oral iron supplements for patients with IDA.
Key Findings
- Vitamin C enhances iron absorption, but the optimal dosage is not clearly established 3, 4, 5, 6.
- Iron supplements given on alternate days and in single doses may optimize iron absorption 5.
- The addition of vitamin C to iron supplements may not be essential for patients with IDA 6.