In This Issue (< 3 min read)

• ​Iron Supplementation: Rethinking Frequency and Absorption​

In this week’s issue, I’m focusing on a practical but important topic: iron supplementation. When we don’t see the expected rise in ferritin, it’s worth looking closely at timing and other factors that can interfere with absorption before changing the type of iron, so I wanted to walk through this with you.

Iron Supplementation: Rethinking Frequency and Absorption

Evidence in the last several years shows that iron absorption from supplements is higher when taken on alternate days rather than on consecutive days, particularly in women with iron deficiency anemia.

This is largely due to hepcidin, a hormone that regulates iron absorption. After an iron dose, hepcidin levels rise and temporarily reduce the body’s ability to absorb additional iron. With daily dosing, hepcidin can remain elevated, limiting absorption. Alternate-day dosing allows hepcidin levels to return closer to baseline, improving overall uptake.

Alternate-day dosing is also often better tolerated, with fewer gastrointestinal side effects such as constipation, nausea, and abdominal discomfort.

How to Take Iron for Optimal Absorption

Iron absorption is influenced by timing and co-ingestion with certain foods and substances.

Avoid taking iron with:

• Coffee and tea
• Milk and calcium-rich foods
• High-fibre foods and cereals
• Carbonated beverages containing phosphates
• Multivitamins or supplements containing calcium, zinc, manganese, or copper
• Antacids, H2 blockers, and proton pump inhibitors
• Quinolone and tetracycline antibiotics

Iron can be taken with:

• Vitamin C
• Acidic foods (e.g., tomato sauce)
• An empty stomach (e.g., at bedtime)

The American Gastroenterological Association recommends taking iron with approximately 80 mg of vitamin C on an empty stomach. Vitamin C enhances absorption by forming a chelate with iron and reducing ferric iron to the more absorbable ferrous form. Most iron supplements contain vitamin C for this very reason.

If taking iron on an empty stomach is not tolerated, it may be taken with food. Consuming iron with animal protein can improve absorption, and a higher dose of vitamin C (e.g., 500 mg) may help offset some inhibitory effects of calcium or fibre.

The Coffee–Iron Interaction You Don’t Want to Miss

Coffee can significantly interfere with iron absorption, and timing makes a meaningful difference.

When coffee is consumed at the same time as iron, or within one hour after, absorption is substantially reduced. However, having coffee at least one hour before taking iron does not appear to have the same inhibitory effect.

It’s also important to note that coffee can override the benefits of vitamin C. In iron-deficient women, consuming coffee with a meal reduced iron absorption by approximately 66%, even when the meal contained about 90 mg of vitamin C. In contrast, taking iron with orange juice alone, without coffee, resulted in roughly fourfold higher absorption and a significantly greater amount of iron absorbed per dose.

Warmly,

Dr. Dominika Zarzeczny Naturopathic Doctor ​ 📧 hello@drdominika.com​ 🌐 www.drdominika.com ​🗓️ Schedule an Appointment​ ​​​

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