Written By: Gloria Tsang, RD
Title: Founding Registered Dietitian
Alumni: University of British Columbia
Last Updated on:
Is Spinach a Good Source of Iron? Cooked Better Than Raw?
Touted as a high iron food, spinach jumped to center stage when it appeared in every episode of Popeye the Sailor Man from 1930s to 60s. So, should Popeye stick to eating his canned spinach? Or should he eat it raw?
Table of Contents
Iron Content: Raw Spinach vs. Cooked Spinach
Spinach is a source of non-heme iron, which is found in vegetable sources. Non-heme iron is not as bioavailable to the body as the heme iron found in animal products.
| (per 1 cup) | Raw Spinach | Cooked Spinach |
| Iron | 0.8 mg | 6.5 mg |
| Calcium | 30 mg | 245 mg |
Plus, spinach shrinks like crazy once it’s cooked! For cup-to-cup comparison, you’re likely eating 5 times more spinach if you choose to eat cooked!
Cooking Spinach Helps Reduce Inhibitor Oxalate Content
Spinach contains an inhibitor called oxalic acid or oxalate. Oxalate naturally binds with minerals like calcium and iron, making them harder for the body to absorb. As oxalate is water-soluble, cooking spinach helps reduce the amount of oxalate, and can help unlock these iron absorption inhibitors and hence increase iron bioavailability. In other words, cooking spinach helps make iron more available to your body.
Remember, men need 8 mg of iron per day, while pre-menopausal women need 18 mg (pregnant women need 27 mg). So, cooked spinach does provide a significant source of iron!
Should You Stop Eating Raw Spinach?
No, unless you have kidney disease, or your doctor recommended you to avoid it. Oxalate is naturally present in many foods; whole grains such as buckwheat and amaranth, vegetables such as chard and rhubarb, beans, and nuts all contain oxalate. If you are going to eat spinach (raw or cooked) and other iron-rich foods, pair them with the following iron absorption enhancers:
- Meat, fish, or poultry
- Fruits: Oranges, orange juice, cantaloupe, strawberries, grapefruit, and other Vitamin-C-rich fruits
- Vegetables: Broccoli, Brussels sprouts, tomatoes, tomato juice, potatoes, and green and red peppers
- White wine
The Bottom Line
It turns out that Popeye made the right decision eating his canned cooked spinach. Certainly, we have more fresh produce available now than in the ’20s, when the cartoon was first created. As water-soluble vitamins are lost during boiling, the best way to cook spinach is steaming or dry cooking like microwave cooking or stir-frying.
Tell Us: How do you cook your spinach?
Alumni: University of British Columbia – Gloria Tsang is the author of 6 books and the founder of HealthCastle.com, the largest online nutrition network run by registered dietitians. Her work has appeared in major national publications, and she is a regularly featured nutrition expert for media outlets across the country. The Huffington Post named her one of its Top 20 Nutrition Experts on Twitter. Gloria’s articles have appeared on various media such as Reuters, NBC & ABC affiliates, The Chicago Sun-Times, Reader’s Digest Canada, iVillage and USA Today.
iron, pregnancy, spinach, vegetables, vegetarian
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Interesting information. Thank you. I have searched for years for information about juicing all the wonderful green vegetables we need without a lot of success. Sixteen years ago radiation for a tumor damaged my intestines which means I can no longer have raw greens, anything with skins, etc. Since I can not have any insoluble fiber would juiced spinach, broccoli, and numerous other foods be an acceptable substitute?