From the Guidelines
Taking iron supplements with vitamin C is recommended to improve iron absorption, particularly for non-heme iron found in plant foods and supplements. When you consume iron with vitamin C (ascorbic acid), the vitamin C enhances iron absorption by forming a chelate with iron that prevents the formation of insoluble iron compounds and by reducing ferric to ferrous iron 1. For optimal absorption, take your iron supplement with a glass of orange juice or a vitamin C supplement (about 75-100 mg) on an empty stomach, about an hour before meals or two hours after eating. However, if stomach upset occurs, you can take it with a small amount of food.
Key Considerations
- Avoid taking iron with calcium-rich foods, coffee, tea, or dairy products, as these can reduce absorption 1.
- Iron supplements come in various forms including ferrous sulfate, ferrous gluconate, and ferrous fumarate, typically in doses of 65-325 mg.
- Vitamin C works by converting iron into a more absorbable form and by preventing the formation of insoluble iron compounds in the digestive tract, making more iron available for your body to use.
Best Practice
The most recent and highest quality study recommends adding vitamin C to oral iron supplementation to improve absorption 1. This is supported by a recent iron isotope study that showed taking iron with 80 mg ascorbic acid on an empty stomach improves iron absorption 1.
From the Research
Iron Supplements and Vitamin C
- The relationship between iron supplements and Vitamin C (Ascorbic Acid) has been studied in various research papers 2, 3, 4, 5, 6.
- According to a 1999 study, Vitamin C contributes to the prevention of iron deficiency anemia by promoting the absorption of dietary non-heme iron, especially in persons with low iron stores 2.
- A 2023 systematic review and meta-analysis found that the addition of Vitamin C to iron supplements did not significantly improve hemoglobin or ferritin levels in patients with anemia 3.
- However, a 1999 study on patients who underwent gastric bypass surgery suggested that taking Vitamin C with iron supplements may enhance the therapeutic effect of iron by correcting ferritin deficits and anemia 4.
- A 2020 randomized clinical trial found that oral iron supplements alone were equivalent to oral iron supplements plus Vitamin C in improving hemoglobin recovery and iron absorption in patients with iron deficiency anemia 5.
- Another 2023 study found that taking iron supplements in the morning with an AA-rich food or beverage, such as orange juice, can increase iron absorption by up to 4-fold compared to consuming it with coffee or breakfast 6.
Key Findings
- Vitamin C can enhance iron absorption, especially in individuals with low iron stores 2, 4, 6.
- The addition of Vitamin C to iron supplements may not be essential for patients with iron deficiency anemia 3, 5.
- The timing and dietary context of iron supplement consumption can significantly impact iron absorption 6.