Difference Between Heme and Nonheme Iron

The main difference between heme and nonheme iron is that the heme iron comes from animal sources while the nonheme iron comes from plant sources. Furthermore, another difference between heme and nonheme iron is that the absorption rate of heme iron is high while the absorption rate of nonheme iron is comparatively low. 

Heme iron and nonheme iron are two types of sources of iron found in the diet. Iron is an important nutrient in the production of hemoglobin, which is the oxygen-carrying pigment in all vertebrates except white-blooded fish. 

Key Areas Covered 

1. What is Heme Iron
     – Definition, Sources, Health Effects
2. What is Nonheme Iron
     – Definition, Sources, Health Effects
3. What are the Similarities Between Heme and Nonheme Iron
     – Outline of Common Features
4. What is the Difference Between Heme and Nonheme Iron
     – Comparison of Key Differences

Key Terms 

Absorption Rate, Bioavailability, Health Risks, Heme Iron, Nonheme Iron 

What is Heme Iron 

Heme iron is the iron found in animal sources such as red meat, poultry, and fish. Some other heme iron-rich foods are oysters, beef liver, and sardines. The term ‘heme iron’ is due to the heme protein attached to the iron. Around 15-35% of the heme iron in the diet is absorbed by the body. Heme iron can also be consumed through animal-based iron supplements. 

Figure 1: Red Meat

Though iron is an essential nutrient, too much of it can cause oxidative stress. Too much heme iron also has a risk of coronary heart disease, stroke, and some types of cancers. On the other hand, iron deficiency causes anemia. Hence, maintaining the right iron balance is critical. 

What is Nonheme Iron 

Nonheme iron is the iron found in plant sources such as beans, nuts, lentils, greeny-leaves such as spinach, and pumpkin seeds. The iron in eggs and dairy products are also considered as nonheme iron. However, the absorption rate of nonheme iron is less (2-20%) when compared to heme iron. Taking vitamin C increases the iron absorption.  

Figure 2: Lentils

Consuming nonheme iron does not lead to an iron excess iron the body. In addition, the consumption of plant sources provides other important metabolites such as antioxidants and phytochemicals, which support the overall health.  

Similarities Between Heme and Nonheme Iron 

• Heme and nonheme iron are two types of dietary sources of iron. 
• Both are important in the production of hemoglobin, which is the oxygen-carrying pigment in most of the vertebrates. 

Difference Between Heme and Nonheme Iron 

Definition 

Heme iron refers to the iron that comes from the animal sources while nonheme iron refers to the iron that comes from plant sources. 

Bioavailability 

The heme iron occurs in oysters, red meat, poultry, beef liver, and fish like sardines while nonheme iron occurs in beans, nuts, lentils, greeny-leaves such as spinach, and pumpkin seeds.  

Heme Group 

Heme iron consists of a heme protein attached to the iron while nonheme iron does not contain a heme protein attached to the iron. 

Absorption Rates 

The absorption rate of heme iron is high while the absorption rate of nonheme iron is comparatively low. 

Health Risks 

Excess heme iron can cause health risks while nonheme iron does not cause health risks. 

Conclusion 

Heme iron is the type of iron source that can be obtained through animal sources while nonheme iron can be obtained through plant sources. Excess heme iron can cause iron toxic conditions. The main difference between heme iron and nonheme iron is their bioavailability. 

Reference:

1. “About Iron.” Iron for Seniors – Feosol, Available Here

Image Courtesy:

1. “2588760” (CC0) via Pixabay
2. “3 types of lentil” (CC BY-SA 2.0) via Commons Wikimedia