One of my vegan cooking gurus, Isa Chandra Moskowitz, recently posted directions for producing perfectly browned tofu. She advises making it in a well-seasoned cast iron pan. I don’t have a cast iron pan, but am thinking about getting one. I eat tofu every single day, and love when it’s perfectly browned, so it deserves its own cookware.
Lately, though, people seem to be abandoning their cast iron pans. They are worried about the iron leaching into their food and causing iron overload.
It’s true that cooking in cast iron (and also stainless steel) can increase the iron content of your food. (1) It’s also true that high stores of iron may be unhealthy, promoting both heart disease and cancer, although this is a theory that has lost some ground lately. (2,3) Iron accumulation in the brain is also linked to Alzheimer’s disease, although whether the accumulation is a consequence or a cause of the disease isn’t known. (4)
Still, iron is a pro-oxidant, which means it can promote harmful oxidative processes in the body, and it’s wise to guard against excessive amounts of stored iron.
So, should you toss your cast iron pan? For a number of reasons, I don’t think you need to do so. First, while cooking any kind of food in these pans can increase its iron content, it’s really those foods that are both liquid and acidic that take up the most iron from these pans. So if you are cooking spaghetti sauce or applesauce in your cast iron pan every night, then, you’re probably getting lots of extra iron. If you’re browning tofu a couple of times per week, you’re only getting small amounts of extra iron.
Second, if your cast iron pan is well-seasoned, it may take up less iron. That thin film of oil is thought to create a barrier between the food and the iron in the pan
And finally—and this is really the thing that made me think about writing this post—we need to remember that when it comes to nutrition and chronic disease, the rules are different for vegans. For example, we can afford to indulge in some refined grains—like pasta or a piece of fresh ciabatta bread—because our diets are already packed with fiber and all the other good things that come from whole plant foods. We can worry less about the amount of fat in our diets because we eat good fats from plants.
And we definitely have less reason to be concerned about excess iron. People with the highest levels of stored iron are usually those who eat a lot of red meat. In the Framingham Heart Study, people who ate at least seven servings of whole grains per week had the lowest stores of iron. (5) I eat way more than seven servings of whole grains per week and I’ll bet you do, too. The reason whole grains protect against iron overload is that they contain phytates, compounds that bind iron and lower its absorption. Vegans absorb much less of the iron in their diets than people who eat meat and therefore tend to have lower stores of iron in their bodies. This is especially true for young (premenopausal) vegan women because they lose iron every month through menstruation.(6)
According to the Food and Nutrition Board, vegans require nearly twice as much iron as meat eaters because of this lower absorption. A little extra from a cast iron pan—especially when it’s used to cook foods that aren’t especially acidic—is not likely to hurt us. And it’s probably helpful for those who are struggling to maintain a healthy iron status.
1. Brittin HC, Nossaman CE. Iron content of food cooked in iron utensils. J Am Diet Assoc 1986;86:897-901.
2. Zegrean M. Association of body iron stores with development of cardiovascular disease in the adult population: a systematic review of the literature. Can J Cardiovasc Nurs 2009;19:26-32.
3. Zhang X, Giovannucci EL, Smith-Warner SA, et al. A prospective study of intakes of zinc and heme iron and colorectal cancer risk in men and women. Cancer Causes Control 2011;22:1627-37.
4. Castellani RJ, Moreira PI, Perry G, Zhu X. The role of iron as a mediator of oxidative stress in Alzheimer disease. Biofactors 2012;38:133-8.
5. Fleming DJ, Tucker KL, Jacques PF, Dallal GE, Wilson PW, Wood RJ. Dietary factors associated with the risk of high iron stores in the elderly Framingham Heart Study cohort. Am J Clin Nutr 2002;76:1375-84.
6. Waldmann A, Koschizke JW, Leitzmann C, Hahn A. Dietary iron intake and iron status of German female vegans: results of the German vegan study. Ann Nutr Metab 2004;48:103-8.
For some data to go with your paragraph about food types and uptake of iron, here’s a post about a study published in the Journal of American Dietician, 1986. They list a chart of foods and the amounts of iron absorbed by the food from a cast iron skillet. http://whatscookingamerica.net/Information/IronCastIron.htm
Aha! I see you sourced the same article! I posted before reading your biblio.
That’s okay, Julia. I’m happy to link to that informative article!
Walter Willet said that heme iron (from red meat, etc) can be overly absorbed, but not non-heme iron. (I think it was in “Eat, Drink, and Be Healthy”.) Which would be another reason for vegans not to worry about too much iron?
Thanks for this post.
Can animals even absorb many minerals from inorganic sources? My understanding is that we do not and require our minerals to first be processed by an organism, like a plant, before we can make much use of them.
Yes, we can. If we couldn’t, led/mercury/etc poisoning wouldn’t be a thing.
I absolutely love my cast iron skillet! I use it every single day for almost everything I cook. And it will probably outlast me!
I use my cast iron pan almost every day for everything. From toast to potstickers to tofu to salads. Ok, maybe not that last one but hmmm, lemme think about it some moar. But before anybody Googles anything about cast irons, it gets pretty culty beware. CAST IRNO FOREVAR!
So yeah I’ve been using it for a while and I terund otu fnie bveilee me!
I recently posted the translation into Spanish of an article posted by Norris on vegetarian children that also applies to vegan ones. A reader asked about her hemophilic son, saying the doctor wouldn’t allow him to be vegetarian or vegan, because he “needs” red meat. Fo you have any information on that? Is that true at all for hemophiliacs?
I’m not Ginny (obviously!) but I have Von Willebrand’s, a blood clotting disorder related to hemophilia, and although my haemotologist tests my iron levels regularly (I’m currently on a low dosage of prescription iron) he knows and is fine about my being a vegan… so I reckon it may well be worth asking a second opinion as even another haemotologist may feel differently. 🙂
I don’t know why someone with hemophilia couldn’t be vegan. Is the issue that people with hemophilia are at at higher risk for iron deficiency anemia? Then it would just be important to monitor their iron status and make sure they are getting enough from plant foods.
Veganism attracts a bunch of foil hat wearing weirdos. Iron and stainless steel cookware is completely safe.
Foil hats? What’s that mean?
I love your sensible blog posts. Thank you. 🙂
thanks for this article. i was a little bit confused by it though. in the case of vegans being on the lower end of iron consumption/iron in their blood (which i believe might be more the case than the opposite?), would it then make sense to watch out for those refined grains?
Vegans aren’t actually on the lower end of iron consumption. We tend to consume more iron than meat-eaters. And eating vitamin C at the same time as the whole grains can help to increase iron absorption. So, for those who are struggling to maintain healthy iron levels, the best idea is to consume more vitamin C-rich foods, rather than fewer whole grains.
I love my cast-iron! I have a virtual army of cast-iron cookware, and there’s no way I could cook without it. One of my pans, that I still use daily, is over a hundred years old. I love that!
Great post. I would hate for people to abandon their cast-iron, especially in favor of that junky non-stick stuff that leaches way worse chemicals than iron into their food.
[…] make it to Home Depot. Lucky for me, I read lots of blogs. Thursday Ginny Messina posted Iron Nutrition: Why the Rules are Different for Vegans and after reading the post I was a wee-bit obsessed about using my cast iron skillet both for […]
[…] iron this week, making my homework much easier. Ginny Messina advises plant-based eaters to think twice before abandoning our cast iron pans, since we seldom need to be concerned about excess […]
My 10 year vegan husband was diagnosed with hemocromatosis around 3 years ago. (Body stores iron and it eventually stores in liver and causes liver disease and death). The interesting thing with iron overload is that the only way to find out if you have it is to have a simple genetic blood test. People with anemia can actually have hemocromatosis, so they are killing themselves with iron supplements! The only reason we know and saved his life was because our Doc had a cousin with the disease and knew about the identified gene. The treatment is easy, give blood every 5 weeks depending on how much iron stores you have. The sad thing is that everyone should have the simple genetic blood test and it would save thousands and millions of lives. To make a long story short, no iron skillets for us:)
I’m so glad you said that about how having a well-seasoned pan probably means less iron leaching. I always think that! I really don’t think anything is coming up from my well-loved, well-seasoned skillet.
That said, it seems like often people have all these worries but no blood work to back it up. If you think you might not be getting enough iron, can’t you just, like, get a blood test and see? If you think you’re getting too much, wouldn’t that show up on blood tests?
Also, I want to add that for browning tofu, I actually find that the best thing is my wok, not my cast iron. Especially if you just coat your tofu cubes in a tiny amount of tamari (like 2 teaspoons for one tofu package) and then cook them in like a tablespoon of olive oil. They cook so nicely that way, in my experience. But cast iron is great too.
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