Written By: Gloria Tsang, RD
Last Updated on:
Spinach jumped to center stage when it appeared in every episode of Popeye the Sailor Man in the ’70s and ’80s. So, should Popeye stick to eating his canned spinach? Or should he eat it raw?
Iron: Raw Spinach versus 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. Raw spinach contains an inhibitor called oxalic acid or oxalate. Oxalic acid naturally binds with minerals like calcium and iron, making them harder for the body to absorb. Cooking spinach 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.
| Raw Spinach (1 cup) | Cooked Spinach (1 cup) | |
| Iron (mg) | 0.8 | 6.5 |
| Calcium (mg) | 30 | 245 |
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!
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! Oxalic acid is naturally present in many foods – spinach is not the only food containing it. Whole grains such as buckwheat and amaranth, vegetables such as chard and rhubarb, beans, and nuts all contain oxalic acid. If you are going to eat raw spinach and other iron-rich foods, perhaps 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?
Gloria Tsang is the author of 5 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.
