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.