The Truth About Green Drinks: Do you get iron from juicing spinach?

November 4, 2025 •

3 min read

Despite the iconic "Popeye effect" myth originating from a misplaced decimal point in a 1930s study, spinach is not the iron powerhouse it is often portrayed to be. This begs the question, do you get iron from juicing spinach, and if so, is your body able to absorb it effectively?.

Quick Summary

While spinach contains iron, it's a less absorbable type known as non-heme iron, and its bioavailability is hindered by naturally occurring compounds like oxalates. Adding Vitamin C-rich foods to your juice or smoothie is crucial for significantly boosting absorption, rather than relying on juicing spinach alone.

Key Points

Low Bioavailability: The iron in spinach is non-heme, which is poorly absorbed by the body compared to the heme iron in animal products.
Oxalates and Polyphenols Inhibit Absorption: Natural compounds like oxalic acid and polyphenols in spinach bind with iron, preventing its uptake.
Vitamin C is Key: To significantly boost iron absorption from spinach juice, you must combine it with Vitamin C-rich ingredients like citrus fruits or pineapple.
Avoid Dairy and Calcium: Consuming calcium-rich foods like dairy alongside your spinach juice will inhibit iron absorption, so it's best to avoid this combination.
Blending Retains Fiber: While juicing removes fiber, blending spinach into a smoothie retains this crucial nutrient, offering a different set of nutritional benefits.
Moderation is Prudent: For individuals prone to kidney stones, consuming excessive spinach juice is not recommended due to its high oxalate content.

The Non-Heme Iron Challenge in Spinach

To understand why it's difficult to absorb iron from spinach, it is essential to distinguish between the two types of iron found in food: heme and non-heme. Heme iron is primarily found in animal products like red meat, poultry, and fish and is much easier for the human body to absorb, with bioavailability rates typically ranging from 15% to 35%. In contrast, spinach contains non-heme iron, which is found in plant-based foods and is significantly less bioavailable. On its own, only a small percentage of non-heme iron is absorbed by the body, often less than 10%.

The Iron Absorption Blockers: Oxalates and Polyphenols

The primary reason for the low bioavailability of iron in spinach is the presence of antinutrients, most notably oxalic acid (oxalates) and polyphenols.

Oxalates: Spinach is exceptionally high in oxalic acid. This compound binds tightly to minerals like iron and calcium, forming insoluble compounds that the body cannot easily absorb. The oxalates essentially hijack the iron, preventing it from being utilized. While cooking can help reduce oxalate levels, a significant amount remains, and juicing does not remove this inhibition.
Polyphenols: Polyphenols, another type of antioxidant, also inhibit non-heme iron absorption. These compounds are present in spinach and other plant foods, further contributing to the challenge of getting iron from leafy greens.

Juicing vs. Blending: The Effect on Nutrient Delivery

When it comes to preparing spinach, the method you choose can affect the nutritional outcome, particularly concerning fiber retention. Juicing, which extracts the liquid from fruits and vegetables and discards the pulp, provides a concentrated shot of nutrients. However, it removes all the fiber, which is crucial for digestive health. Blending, on the other hand, pulverizes the entire leaf, including the fiber, and retains more of the whole food's nutritional benefits. For iron intake specifically, juicing does not magically overcome the absorption inhibitors, but it does allow for easy combination with other ingredients that can help.

The Vitamin C Solution for Better Absorption

The most effective way to enhance the absorption of non-heme iron from spinach is to pair it with a powerful enhancer: Vitamin C. Ascorbic acid, or Vitamin C, helps convert non-heme iron into a more soluble form, making it easier for the body to absorb. This is why adding fruits high in Vitamin C, such as oranges, lemons, kiwis, or strawberries, to your spinach juice or smoothie is highly recommended. Research has shown that combining spinach with lemon juice can significantly increase iron bioavailability.

Maximizing Iron Absorption in Spinach Juice


Feature	Simple Spinach Juice	Optimized Spinach Juice with Vitamin C
Ingredients	1 cup spinach, 1 cup water	1 cup spinach, 1 cup orange juice, ½ cup pineapple, 1 tbsp lemon juice
Iron Content	Contains non-heme iron.	Contains non-heme iron from spinach.
Absorption Rate	Very low, as low as 2%.	Significantly higher due to high Vitamin C content.
Key Inhibitors	High oxalate and polyphenol content limit absorption.	Vitamin C helps overcome inhibitors.
Nutritional Profile	Good source of Vitamins A, K, and folate.	Adds extra Vitamin C, enzymes, and a more balanced taste.
Fiber	Juiced spinach contains no fiber.	Blended smoothie retains fiber for better digestion.

Important Considerations for Your Spinach Juice

Avoid dairy: Calcium is another inhibitor of iron absorption, so consuming milk or other dairy products with your spinach juice will counteract the benefits. For example, a spinach smoothie made with cow's milk will have reduced iron absorption compared to one made with water or a plant-based milk alternative.
Moderation is key: While beneficial, excessive consumption of spinach juice could lead to an overload of oxalates, which can cause issues for people prone to kidney stones. A moderate intake of a few times per week is generally recommended.
Blend for fiber: If you prefer to retain the dietary fiber, which is important for digestion and satiety, make a smoothie instead of a juice.
Consult a professional: If you have concerns about iron deficiency, it is crucial to consult a healthcare provider. While iron-rich foods are beneficial, they may not be sufficient to treat a diagnosed deficiency.

In conclusion, you do get iron from juicing spinach, but the amount your body can actually use is minimal without a dietary accomplice. By adding Vitamin C-rich fruits and following mindful practices, you can make your green juice a much more effective source of this essential mineral.

For more information on optimizing nutrient absorption from plant-based foods, you can visit the National Institutes of Health (NIH) Office of Dietary Supplements website for details on iron intake(https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/).

Frequently Asked Questions

No, the iron in spinach is non-heme, which is much less bioavailable and harder for the body to absorb than the heme iron found in meat and other animal products.

Juicing spinach does not, by itself, improve iron absorption. The presence of oxalates and polyphenols in spinach inhibits absorption, and juicing does not remove these inhibitors.

The famous myth about spinach being a super-rich source of iron, often associated with Popeye, stemmed from a decimal point error in a 1930s study. Popeye's creator actually intended to highlight its Vitamin A content.

You can add ingredients rich in Vitamin C, such as oranges, lemons, kiwis, or strawberries, to your spinach juice. Vitamin C helps convert the iron into a more absorbable form.

Adding milk or other dairy products is not recommended if you are trying to increase iron absorption. Calcium can interfere with the body's ability to absorb iron.

Both juicing and blending have pros and cons. Juicing provides a concentrated dose of nutrients without fiber, while blending retains the fiber, which is beneficial for digestion. For maximizing iron absorption, the key is what you add to it, regardless of the preparation method.

Excessive consumption of spinach juice is not recommended, especially for individuals at risk of kidney stones. Spinach is high in oxalates, which can contribute to the formation of kidney stones in large quantities.