How to Increase Iron Absorption
Summary
This article covers the key difference between heme and non-heme iron, and why vegans and plant-based eaters may struggle with iron absorption. Dr. Berg explains how pairing plant-based iron sources with natural vitamin C can significantly improve bioavailability.
Key Takeaways
- Heme iron (from animal sources) absorbs more efficiently than non-heme iron (from plant sources)
- Vegans and plant-based eaters are at a disadvantage because non-heme iron has lower bioavailability
- Natural vitamin C can meaningfully boost the absorption rate of non-heme iron
- Whole food sources of vitamin C are preferred over synthetic supplements
- Best vitamin C sources to pair with iron: lemons, blackberries, raspberries, and bell peppers
- Avoid synthetic iron forms like ferric oxide and ferric hydroxide, commonly found in pill supplements
- Timing matters — consume vitamin C-rich foods at the same meal as your iron sources
Details
Heme vs. Non-Heme Iron
Heme iron, derived from animal products, is absorbed more readily by the body. Non-heme iron, which comes from plant-based sources such as vegetables, legumes, nuts, and seeds, is significantly less bioavailable. This is a particular concern for vegans and vegetarians who rely entirely on plant sources to meet their iron needs.
The Role of Vitamin C in Iron Absorption
Vitamin C enhances the absorption of non-heme iron by helping convert it into a form the body can more easily take up. However, Dr. Berg specifically recommends natural, whole-food sources of vitamin C over synthetic supplements.
Recommended vitamin C sources:
- Lemons — whole lemons that are cut and squeezed fresh (not bottled lemon juice)
- Blackberries and raspberries — highlighted as among the best berry options
- Bell peppers — another high-vitamin C food suitable for pairing with iron-rich meals
What to Avoid
Synthetic iron compounds commonly found in multivitamins and iron supplements — specifically ferric oxide and ferric hydroxide — are not recommended. These forms are typically bundled with other synthetic vitamins and are considered inferior choices for iron supplementation.
Practical Protocol
When eating plant-based iron sources (legumes, nuts, seeds, leafy vegetables), include one or more of the recommended vitamin C foods in the same meal to take advantage of the absorption-enhancing effect.