What Type of Iron Found in Plant Foods Is Called? Understanding Non-Heme Iron

While heme iron is more readily absorbed from animal products, the iron found in plant foods, called non-heme iron, is also a vital nutrient. Non-heme iron represents a significant percentage of the total iron intake for many people, especially those on vegetarian or vegan diets. Knowing what type of iron found in plant foods is called is the first step toward optimizing your dietary iron intake.

Quick Summary

The type of iron found in all plant-based foods is called non-heme iron, and its absorption is influenced by dietary factors. Strategic pairings with Vitamin C can significantly increase absorption, countering the effects of inhibitors like phytates and polyphenols found in some plants.

Key Points

• Non-heme iron: This is the type of iron found exclusively in all plant foods, such as vegetables, fruits, nuts, seeds, and legumes.

• Lower absorption: Non-heme iron is absorbed less efficiently by the body than heme iron from animal products, though absorption can be enhanced.

• Absorption enhancers: Combining non-heme iron sources with Vitamin C-rich foods, like citrus fruits and bell peppers, can significantly boost absorption.

• Absorption inhibitors: Compounds such as phytates in grains, calcium in dairy, and polyphenols in tea and coffee can hinder non-heme iron uptake.

• Dietary strategy: To maximize intake, individuals should pair iron-rich plant foods with enhancers and time the consumption of inhibitors.

• Important for vegans: Individuals on plant-based diets should be particularly mindful of optimizing non-heme iron absorption through strategic meal planning.

The Two Forms of Dietary Iron: Heme vs. Non-Heme

Iron is an essential mineral vital for producing hemoglobin, the protein in red blood cells that carries oxygen throughout the body. It is also crucial for energy production, DNA synthesis, and immune function. The iron we consume from food comes in two distinct forms: heme and non-heme iron. The primary difference lies in their source and how efficiently our bodies absorb them.

What is Non-Heme Iron?

Non-heme iron is the type of iron found in all plant foods, including vegetables, fruits, nuts, seeds, and legumes. It is also the type of iron used to fortify many processed foods like cereals and breads. Unlike its counterpart, non-heme iron is less efficiently absorbed by the body, with an absorption rate ranging from 2% to 20%. However, this rate can be significantly influenced by what other foods are consumed with it. For those on plant-based diets, understanding and optimizing non-heme iron absorption is crucial for preventing deficiency.

What is Heme Iron?

Heme iron is the type of iron derived from animal flesh, such as meat, poultry, and seafood. This form of iron is part of hemoglobin and myoglobin and is more readily absorbed by the body, with an absorption rate of 15% to 35%. Animal products contain both heme and non-heme iron, but it is the heme component that is the most bioavailable. The presence of heme iron in a meal can also boost the absorption of non-heme iron from other foods consumed at the same time.

Sources of Non-Heme Iron in Plant Foods

For vegetarians, vegans, and anyone looking to increase their non-heme iron intake, a wide variety of delicious and healthy foods can help. The key is to include a diverse selection of these items in your diet to meet daily requirements.

• Legumes: Lentils, chickpeas, soybeans, and all varieties of beans (kidney, black, lima) are excellent sources. A single cup of cooked lentils provides a substantial amount of iron.
• Dark Leafy Greens: Spinach, kale, Swiss chard, and collard greens are packed with non-heme iron. While raw spinach contains iron, cooking it can actually increase its availability for absorption by reducing oxalates.
• Nuts and Seeds: Pumpkin seeds, sesame seeds, almonds, cashews, and pistachios all contain good amounts of iron. They make for a convenient, nutrient-dense snack.
• Whole Grains: Fortified cereals, oats, quinoa, and brown rice are valuable sources, particularly for those on plant-based diets. Soaking or sprouting grains can help improve iron bioavailability.
• Dried Fruits: Apricots, raisins, and prunes are easy to incorporate into your diet and contain significant amounts of non-heme iron.
• Tofu and Tempeh: These soy-based products are a staple in many vegan and vegetarian diets and are rich in non-heme iron and protein.

Factors Affecting Non-Heme Iron Absorption

The absorption of non-heme iron is highly dependent on meal composition, which is why strategic eating is so important. Certain compounds can act as either enhancers or inhibitors of absorption.

• Absorption Enhancers

  • Vitamin C: This is the most potent enhancer of non-heme iron absorption. Consuming foods high in vitamin C, such as citrus fruits, bell peppers, tomatoes, and broccoli, alongside your iron-rich meal can increase absorption dramatically.
  • Beta-Carotene and Vitamin A: These vitamins also improve non-heme iron absorption. Sweet potatoes, carrots, spinach, and kale are excellent sources.
  • Heme Iron: As mentioned, consuming some heme iron (meat, poultry, fish) can also boost the absorption of non-heme iron in the same meal.

• Absorption Inhibitors

  • Phytates: Found in whole grains, legumes, nuts, and seeds, phytates can bind to iron and hinder its absorption. Soaking, sprouting, or fermenting these foods can help reduce their phytate content.
  • Calcium: This mineral can interfere with both heme and non-heme iron absorption. It is best to avoid consuming large amounts of calcium-rich foods or supplements at the same time as iron-rich meals.
  • Polyphenols: These compounds are present in coffee and tea and can inhibit non-heme iron absorption. It is recommended to separate the consumption of these beverages from iron-rich meals by a few hours.

How to Maximize Non-Heme Iron Absorption

For individuals relying on plant-based sources, maximizing non-heme iron absorption is a priority. Here are some actionable steps to take:

1. Pair with Vitamin C: Always add a source of vitamin C to your iron-rich meals. For example, add bell peppers to a lentil chili, or squeeze lemon juice over a spinach salad. This is one of the most effective strategies.
2. Use a Cast Iron Skillet: Cooking your food in a cast iron skillet can significantly increase the iron content of the meal, as some of the iron leaches into the food.
3. Time Your Drinks: Drink your tea or coffee a few hours before or after an iron-rich meal to prevent the polyphenols from inhibiting absorption.
4. Consider Preparation Methods: Properly soaking or sprouting your legumes and grains before cooking can reduce phytates and improve the bioavailability of the non-heme iron they contain.
5. Plan Calcium Timing: If you need to take a calcium supplement, take it at a different time of day than your main iron-rich meal.

Heme vs. Non-Heme Iron: A Comparison

To summarize the key differences, the following table provides a clear breakdown of the two types of dietary iron.

Feature	Heme Iron	Non-Heme Iron
Source	Animal products (meat, poultry, fish)	Plant foods (legumes, nuts, greens) and fortified foods
Absorption Rate	High (15-35%)	Low (2-20%), but varies widely
Influencing Factors	Less affected by other foods in a meal	Highly influenced by other dietary components (enhancers and inhibitors)
Effect on Absorption	Absorbed intact, relatively stable	Forms an exchangeable pool, susceptible to inhibitors
Body Regulation	Poorly regulated; higher risk of overload with high intake	Tightly regulated by the body; absorption increases when iron stores are low

Conclusion

Understanding what type of iron found in plant foods is called—non-heme iron—is essential for anyone managing their diet, particularly those on a plant-based eating plan. While non-heme iron is not as easily absorbed as heme iron, its bioavailability is not a barrier to maintaining adequate iron stores. By strategically combining non-heme iron sources with enhancers like Vitamin C and being mindful of inhibitors, you can effectively meet your body's iron needs. A varied and balanced diet that includes a wide range of iron-rich plant foods is the best strategy for promoting good iron status and overall health. For further reading on dietary iron, refer to the Harvard T.H. Chan School of Public Health Nutrition Source.

Frequently Asked Questions

What is the difference between heme and non-heme iron?

Heme iron comes from animal sources and is more easily absorbed by the body. Non-heme iron is found in plant foods and fortified products and is absorbed less efficiently, with its uptake highly dependent on other dietary factors.

Which plant foods are the best sources of non-heme iron?

Excellent sources include legumes (lentils, beans, chickpeas), dark leafy greens (spinach, kale), nuts and seeds (pumpkin seeds, cashews), and whole grains (quinoa, fortified cereals).

How can I increase my non-heme iron absorption?

The most effective way is to pair non-heme iron-rich foods with a source of Vitamin C. Other methods include cooking in a cast iron skillet and soaking or sprouting legumes and grains.

Do vegetarians and vegans get enough iron?

While plant-based diets only contain less-absorbable non-heme iron, with proper planning, vegetarians and vegans can meet their iron requirements by focusing on iron-rich plant foods and employing strategies to enhance absorption.

What substances should be avoided with iron-rich meals?

To avoid inhibiting absorption, it's best to separate the consumption of tea, coffee, and calcium-rich foods (like dairy) from your main iron-rich meals by a few hours.

Can cooking methods affect iron content in food?

Yes, cooking in a cast iron skillet can add iron to your food. Additionally, cooking certain greens like spinach can help reduce inhibitors like oxalates, which can improve iron availability.

Is it possible to absorb too much non-heme iron?

Unlike heme iron, the absorption of non-heme iron is tightly regulated by the body. This helps prevent iron overload in most people. Absorption naturally increases when the body’s iron stores are low and decreases when they are sufficient.