Can Japanese Tea Pots Increase Dietary Iron


Someone recently told me using Japanese cast iron tea pots is a way to introduce iron into one’s diet. I guess the theory is similar to using cast iron frying pans, which I’ve heard can do the same. One significant exception is Japanese pots are glazed inside. Makes me doubt any iron would seep into the tea. After all, if the pots aren’t glazed wouldn’t they rust?

This is a great question. Although it sounds like wishful thinking, you can get dietary iron from cast iron . Tiny molecules of the iron from the cookware hitch a ride with the food that’s being cooked and end up in our system (boosting our iron intake). A classic 1986 study, published in the Journal of the American Dietetic Association, tested 20 different foods after being cooked in cast iron — all of them had some iron increase post-cooking.

But, as you suggested, coated cast iron won’t really work.

Some cast iron cookware is “enamelled,” meaning it has a coating on the cooking surface. This cookware takes advantage of the great heat conducting properties of the iron, but the enamel keeps the food from coming in contact with the iron itself. This cookware is often favored by people who want the quality sturdiness of cast iron without the worry of upkeep (taking care of un-enamelled cast iron requires a little more care than your average pot to prevent rusting).

I’m not sure what sort of glaze they’re using in Japanese tea pots (it might be worth checking into to make sure there’s no harmful constituents in the glaze, like lead). But it’s safe to say if the iron interior of the pot never comes into contact with the actual tea, it’s probably not transferring any iron.

Studies have found the acidity of foods cooked in cast iron has an effect on whether or not iron is absorbed, too. A Brazilian study, published in the journal Ecology of Food & Nutrition in 2007, found for a food to absorb any iron, it has to be both acidic and water-based (like tomato sauce).

It’s ironic then, as a general rule, that cooking wet foods in cast iron cookware should be avoided (liquid substances tend to ruin the “seasoning” the pans build up over time — seasoning being thin layers of healthy oils). That rule is also why you generally shouldn’t use soap when washing anything cast.

With a pan, you can always rub a little oil on after you’re done cleaning in order to protect any exposed iron from rusting. But you wouldn’t want to do this with a tea pot, unless you happen to enjoy oily tea. For this reason, I can only guess you’re right, T — cast iron tea pots do not make for good sources of iron.

On another note, this study found tea consumption can actually interfere with iron absorption in those relying on non-heme sources (vegetarian ones). And remember, how much iron you take in is less important than how much iron you absorb.

The Healthy Foodie is Doug DiPasquale, Holistic Nutritionist and trained chef, living in Toronto.

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