About as much iron(y) as a tin can hold

A healthy spinach plant.

Green stuff that’s actually good for you.

Do you eat your greens? Many kids the world over have been cajoled conned persuaded reminded by their parents to eat their vegetables in order to be strong and healthy. If your mom/ dad/ grandma/ other authority figure in your life is anything like mine, you may be told that if you eat your spinach, you’ll be as strong as Popeye the sailor man. Despite all your protests about the taste.

Thumper knows what’s up.

Does spinach actually make you strong?

Popeye eating a can of spinach.

I’ve always wanted to know how he popped the can open beforehand, actually. Image credit: King Features

The image of Popeye taking the baddies out with a punch after downing a can of spinach is a common perception that seemingly supports the idea that spinach improves physical performance. What’s not commonly known is how that idea came to be.


An honest mistake…but that’s not the point

You'll see why in a bit. Image credit: Frank and Ernest

You’ll see why in a bit.
Image credit: Frank and Ernest

In 1870,a German chemist, Ehrich von Wolf, was investigating the iron content of different types of vegetables, spinach being one of them. He found that a 100-gram serving of spinach contained 3.5 milligrams of iron. But when he recorded his findings, he mistakenly wrote it down as 35 milligrams, misplacing the decimal point. That’s ten times more iron than the actual amount!

As a result, von Wolf’s research led many people to believe that spinach had such health properties. This error wasn’t discovered until 1937, but many people still believe in eating spinach for good health.

Pumping iron: how does spinach measure up?

Given that iron is important in your diet to stay alert and avoid nasty diseases like anaemia, we decided to see if it was better to eat like Popeye or J. Wellington Wimpy. A quick look at the USDA’s food database yielded the following figures. Apparently, spinach isn’t the only food you can eat to keep your iron levels up.


Food Spinach (boiled) Yam (boiled) Olive oil White rice (cooked) Hamburger Wheat cereal
Iron content (milligrams per 100g serving) 3.6 0.5 0.6 1.2 3.1 62.1

Ironing out the details

The amount of iron you need depends on your age, gender, and whether you’re pregnant or a nursing mother. Iron deficiency can mess with your gastrointestinal and cognitive functions, as well as your body’s ability to regulate its temperature. It can be even more damaging for growing children, where a lack of iron can interfere with their physical and mental development. In severe cases, the effects of the deficiency can last into adulthood.

Iron in excess

Too much iron can cause you to feel faint and suffer from an upset stomach, constipation, nausea and vomiting. Children can die from excess iron intake, so keep those iron supplements out of reach of children and stick to the recommended intake below.


Age Male Female Pregnancy Lactation
Birth to 6 months 0.27 mg* 0.27 mg*
7–12 months 11 mg 11 mg
1–3 years 7 mg 7 mg
4–8 years 10 mg 10 mg
9–13 years 8 mg 8 mg
14–18 years 11 mg 15 mg 27 mg 10 mg
19–50 years 8 mg 18 mg 27 mg 9 mg
51+ years 8 mg 8 mg

* Adequate Intake (AI)

Source: National Institutes of Health

You are what you eat (but I yam what I yam)


Disclaimer: This post is not in any way an endorsement of hamburgers. Image credit: King Features

Ultimately, eating spinach isn’t the only food you can eat to keep your iron levels up. (Sorry, mom!) Popeye the sailor man will probably get by just as fine, iron-wise on a diet of spinach, rice, yams or cereal (with a touch of Olive Oyl) as Wimpy will be with his hamburgers. But Mom is still right about one thing when it comes to iron consumption. Moderation is a virtue. And the Zap Zap Math team would also add another.

Never misplace a decimal point!

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