NANP Board Practice Exam

Which type of iron is more easily absorbed by the human body?

1. Ferrous Iron

2. Ferric Iron

3. Heme Iron

4. Non-heme Iron

The correct answer is: Heme Iron

The body more easily absorbs heme iron, which is found in animal products such as meat, poultry, and fish. This type of iron is integral to hemoglobin and myoglobin, making it more bioavailable to humans. Heme iron is absorbed through a different mechanism than non-heme iron, leading to a higher absorption rate, typically ranging from 15% to 35% compared to non-heme iron which has a lower absorption rate of around 2% to 20%. While ferrous iron (the reduced form of iron) is more soluble and can be better absorbed than ferric iron (the oxidized form), heme iron stands out because of its origin and absorption efficiency in the human digestive system. Non-heme iron, found primarily in plant sources, is less efficiently absorbed due to various dietary factors that can inhibit its uptake.