Is Spinach a Good Source of Iron? Cooked Better Than Raw?

Written By: Gloria Tsang, RD

Title: Founding Registered Dietitian

Alumni: University of British Columbia

Last Updated on:

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?

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 SpinachCooked Spinach
Iron0.8 mg6.5 mg
Calcium30 mg245 mg
Table 1. Iron and calcium content in raw vs cooked spinach.

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!

All about spinach. Is raw spinach better than cooked ones in terms of iron absorption?

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?

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1 thought on “Is Spinach a Good Source of Iron? Cooked Better Than Raw?”

  1. 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?


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