Iron deficiency is the world's most common nutritional disorder. As many as two billion people have anaemia, mainly from not getting enough iron in their diet, according to the World Health Organisation (WHO). So, other than eating more iron-rich foods, another good way to increase iron intake is to cook foods in a cast iron pan. In their article, Examine.com looks at how cooking in a cast iron pan can impact iron levels in foods. It turns out that the amount of iron that can leach into foods is quite significant. For example, a fried egg that's been cooked in a cast iron pan contains approximately 2mg more iron than one cooked in a regular pan. Apparently, iron levels in even pancakes can be boosted from 0.81mg to 1.31mg, but cast iron pans don't seem to increase iron levels in all foods. Additionally, it's the non-heme form of iron, which means you're able to absorb less iron compared to heme iron from red meats; but vitamin C and other acids can increase iron absorption.
A caveat: While certain groups of people, such as menstruating and pregnant women, vegans and vegetarians, can benefit from more iron, iron intake for other groups of people can add up quickly, especially if you cook all of your foods in a cast iron pan every day. You'll want to be careful not to get too much. For healthy adult men, the daily recommended dose is 8mg; 18mg for healthy adult women. Too much at once can be toxic and lead to harmful effects, such as fevers, chills, blue-ish lips and nails and liver damage.
If you cook in a cast iron pan, it's worth noting that longer cooking times, a newer pan (as opposed to one that is old and well-seasoned) and liquid foods tend to leach more iron into your foods. For more about iron overload or the different ways cast iron pans can help increase iron intake, head over to the Examine.com article.
Are Cast Iron Pans Unsafe? [Examine.com]