Is Oregano Good for Iron? Separating Fact from Fiction

November 4, 2025 •

4 min read

According to USDA data, dried oregano contains a surprisingly high concentration of iron, but its effect on your body's iron levels is more complex. The question, 'Is oregano good for iron?' requires a closer look at serving sizes and the herb's natural compounds, such as tannins, that can interfere with mineral absorption.

Quick Summary

Oregano provides iron, but its tannins can inhibit absorption, especially in concentrated oil forms. While a good source of vitamins and antioxidants, it is not a practical primary iron source, and supplements should be taken cautiously if anemic.

Key Points

High Iron Concentration per Weight: Dried oregano contains a significant amount of iron per 100 grams, but typical serving sizes are too small to make it a practical primary iron source.
Tannins Inhibit Absorption: Oregano contains tannins and other polyphenols that can bind to and inhibit the absorption of non-heme iron from plant-based foods.
Concentrated Oil Requires Caution: The risk of inhibited iron absorption is highest with concentrated oregano oil supplements, and people with iron deficiency should consult a doctor before use.
Culinary Use is Safe: Using small amounts of dried oregano for cooking is unlikely to have a significant impact on your body's overall iron absorption.
Boost Absorption with Vitamin C: To counteract the effect of tannins, pair iron-rich meals seasoned with oregano with foods high in vitamin C.
More than Just Iron: Despite its limitations as an iron source, oregano is rich in antioxidants and has beneficial antimicrobial and anti-inflammatory properties.

The High Iron Content of Oregano: A Closer Look

At first glance, oregano appears to be an iron powerhouse. When measured per 100 grams, dried oregano contains a very significant amount of iron, along with other essential minerals like calcium and manganese. However, this is where a critical distinction needs to be made: the iron content measured in bulk does not translate to meaningful iron intake during typical culinary use.

Dried vs. Fresh Oregano

Dried Oregano: Contains a highly concentrated nutritional profile. Just one teaspoon (approx. 1 gram) has about 0.4mg of iron, which is still a very small amount in the context of daily dietary needs.
Fresh Oregano: Has a much lower iron concentration due to its water content. It offers many of the same health benefits but in smaller quantities per weight.

The Tannin Trade-Off: How Oregano Inhibits Iron Absorption

The seemingly high iron number is misleading because of another compound found naturally in oregano: tannins. Tannins are a class of polyphenols that can bind to non-heme iron—the type found in plant-based foods—and inhibit its absorption in the gut.

The Impact of Tannins and Polyphenols

When consumed, these tannins can make the iron in both the oregano and other plant-based foods in your meal less bioavailable to your body. This inhibitory effect is most pronounced with highly concentrated products.

Culinary Use vs. Supplemental Intake: A Crucial Distinction

The way you consume oregano dramatically impacts its effect on your iron levels. For the vast majority of people using oregano as a seasoning, the impact is negligible.

Oregano in Daily Cooking

When you sprinkle a small amount of dried oregano on pizza or in pasta sauce, the amount of iron is minimal, and the tannins present are unlikely to significantly affect the overall iron absorption of a balanced meal. Using oregano for flavor is perfectly safe and still provides a range of antioxidants and other beneficial compounds.

Risks with Oregano Oil Supplements

For those who take highly concentrated oregano oil supplements, the story changes entirely. These concentrated products deliver a much higher dose of both active compounds and tannins. Health experts advise that individuals with iron deficiency or anemia should be cautious and monitor their iron levels if regularly using such supplements, as they can interfere with iron absorption over time. It is also recommended to take these supplements at least two hours apart from iron supplements.

How to Maximize Iron Absorption from Your Diet

If you want to enjoy oregano while optimizing your iron intake, there are simple strategies to employ:

Pair with Vitamin C: Consuming vitamin C-rich foods (like bell peppers, tomatoes, or citrus) alongside iron-rich meals significantly boosts the body's ability to absorb non-heme iron.
Separate Supplements: Take any iron supplements at a different time of day than concentrated oregano oil supplements to avoid potential interference.
Use Cast-Iron Cookware: Preparing food in a cast-iron pan can help increase the iron content of your meals.

Nutritional Comparison: Oregano vs. Other Iron Sources

To put oregano's iron contribution into perspective, compare it with common, reliable sources of iron.


Food (per 100g)	Iron Content (mg)	Iron Type	Key Co-factors	Absorption Impact
Dried Oregano	~37 mg	Non-heme	Tannins, Vitamin K	Inhibited by tannins
Beef Liver	~22.4 mg	Heme	B Vitamins	Highly bioavailable
Spinach	~2.7 mg	Non-heme	Vitamin C (variable)	Inhibited by oxalates
Lentils (cooked)	~3.3 mg	Non-heme	Folate, Magnesium	Enhanced with Vitamin C

As the table shows, while oregano has a high concentration, you consume it in such small quantities that it is not a primary source of iron. In contrast, organ meats like beef liver provide highly bioavailable heme iron, while legumes offer non-heme iron that can be better absorbed when paired with vitamin C.

Beyond Iron: Other Health Benefits of Oregano

Even with the absorption caveats, oregano remains a healthy addition to your diet. The herb is packed with antioxidants, which help protect cells from damage caused by free radicals. Its compounds, such as carvacrol and thymol, have been studied for their antimicrobial and anti-inflammatory properties.

Conclusion: The Balanced Perspective on Oregano and Iron

So, is oregano good for iron? The answer is nuanced. While dried oregano has a high iron concentration per weight, typical culinary usage provides only a trace amount. More importantly, the tannins it contains can inhibit the absorption of iron, a factor especially relevant for concentrated oil supplements. For most people, enjoying oregano as a culinary herb is a low-risk way to add flavor and antioxidants without significantly impacting iron levels. However, those managing iron deficiency should be mindful of high-dose supplementation and use strategies to enhance absorption when pairing it with plant-based iron sources. The best approach is to enjoy oregano for its flavor and broader health benefits, not as a primary solution for your iron needs. For more details on this herb's benefits and precautions, you can consult reliable sources like the Cleveland Clinic.

Frequently Asked Questions

While dried oregano has a high concentration of iron by weight, a typical serving size, like a teaspoon, contains only a trace amount. It is not considered a significant source of dietary iron for most people.

Yes, highly concentrated oregano oil can interfere with the body's absorption of iron due to its tannin content. Individuals with iron deficiency should be cautious when taking these supplements.

You can enhance iron absorption by pairing iron-rich foods with a source of vitamin C. For example, add tomatoes (rich in vitamin C) to a dish seasoned with oregano to help counteract the inhibitory effects of tannins.

Fresh oregano has a lower concentration of nutrients, including iron and tannins. However, the fundamental issue of tannins inhibiting non-heme iron absorption exists in both forms, so neither is a particularly effective source of absorbable iron.

No, there is no need to avoid all oregano. The small amount used in cooking has a negligible effect. The primary concern is with high-dose oregano oil supplements, which should be discussed with a healthcare provider if you have anemia.

Oregano itself will not cause an iron deficiency, especially when consumed in culinary amounts. However, excessive use of concentrated oregano oil supplements could theoretically interfere with iron absorption enough to matter for those already prone to low iron.

Tannins are compounds found in many plants, including oregano, that can bind to non-heme iron in the digestive tract. This binding prevents the iron from being absorbed by the body.