Iron and Carcinogens in Cast Iron


I have used iron skillets for years. Some belonged to my Mother. A friend asked me if it was safe to use because of the iron in the skillet. I told her I have been eating from them and using them for years & never heard anything about the iron in the skillet not being safe. Please let me know. Thank-you for your informative care of the skillets. – Brenda Weldon (12/16/05)


Yes, cooking in a cast iron skillet can add significant amounts of iron to your food and into your body… if you eat it. This was proven by researchers who tested 20 foods, the results of which were published in the July 1986 issue of the Journal of the American Dietetic Association. They measured the iron and moisture content of these items when raw, and after cooking in an iron skillet and a non-iron (Corning ware) dish, separately. A new, seasoned iron skillet was used, in the event prior use might have affected iron absorption. The researchers also compared iron absorption when using a new iron skillet versus an older one.

Researchers found that cooking in an iron skillet greatly increases the iron content of many foods. Acidic foods that have a higher moisture content, such as applesauce and spaghetti sauce, absorbed the most iron. As a matter of fact, the big winners in the foods tested were these two items. For 100 grams of each (about 3 oz.), the applesauce increased in iron content from 0.35 mg. to 7.3 mg., and the spaghetti sauce jumped from 0.6 mg. to 5.7 mg. of iron.

Food cooked for longer periods of time absorbed more iron than food that was heated more quickly. They also found foods prepared with a newer iron skillet absorbed more iron than those cooked in an older one. Foods that were cooked and stirred more frequently absorbed a greater amount of iron as well, probably because they came into contact with the iron more often. Hamburger, corn tortillas, cornbread, and liver with onions didn’t absorb as much iron. This was probably due to the shorter cooking times, and the fact that they were either turned once or not at all, resulting in less contact with the iron.

Here are the changes the researchers found. Foods cooked at home may vary in iron absorption based on the age of the skillet used and the amount of time the foods are heated. This list can give you a general idea of the difference in dietary iron content cooking in an iron skillet can provide.

Foods tested (100 g./3 oz.)Iron content - rawIron content - cooked in Cast iron  
Applesauce, unsweetened.35 mg.7.38 mg.
Spaghetti sauce0.615.77
Chili with meat and beans.966.27
Medium white sauce.223.30
Scrambled egg1.494.76
Spaghetti sauce with meat.713.58
Beef vegetable stew.663.4
Fried egg1.923.48
Spanish rice.872.25
Rice, white.671.97
Pan broiled bacon.771.92
Poached egg1.872.32
Fried chicken.881.89
Pan fried green beans.641.18
Pan broiled hamburger1.492.29
Fried potatoes.42.8
Fried corn tortillas.861.23
Pan-fried beef liver with onions3.13.87
Baked cornbread.67.86


So, if you’re looking to increase your dietary iron, use a new cast iron skillet. After all, the iron in cookware is no different from the iron in our bodies — except we have much smaller amounts!



A friend recently said that she’d read that cast iron cookware gives of carcinogens. Is this true? – Gary Hollingshead (11/28/05)


I have not read any articles on cast iron cookware containing carcinogens. If you have some articles, please share them with me.

Cooking in cast iron pots can significantly increase the iron content of food, particularly foods with a high moisture content, high acidity and those cooked for a long time. For example, a serving of spaghetti sauce normally contains less than one milligram of iron, but when cooked in an iron pot, that can climb to nearly six milligrams. Whether or not this added iron is a benefit depends on your age and your health status. For most individuals the occasional use of a cast iron skillet will cause no health concerns

I have read that everything grilled or barbecued is full of carcinogens due to the fact that the food is cooked over burning coals, wood and/or gas. The carcinogens intrinsically produced in grilling are mainly free radicals that are produced whenever you heat a hydrocarbon (i.e. butter, fat, burnt-sugar, etc.) to high temperatures. This is why French fries are so unhealthy – not only are they high in fat but they are also loaded with free radicals.

I have also heard that Teflon pans contain carcinogens. A University of Toronto chemist has shown that Teflon coated pans release perfluorooctanoic acid (PFOA), a “likely carcinogen” and other chemicals when heated to 360 celsius.

Did you know that even black pepper contains 32 known carcinogens?

Wow! Pepper has 32 carcinogens!? That is nothing to sneeze at!



I am on a nutrition web program and one of our members brought up the question of how much iron is given off a cast iron skillet into the food you are cooking. Are you aware of any research on this subject? It would be one more benefit to using cast iron skillets. – Cathryn (10/15/05)



Cooking high-acid foods like tomato products or apple sauce in cast iron cook-ware is actually recommended to help increase the amount of iron in your diet.

In fact, in a classic study published in 1986 in the Journal of the American Dietetic Association, researchers tested 20 foods cooked in new cast iron skillets. They found most foods increased in iron content by being cooked in the iron cookware, some significantly so.

Check out all my web pages on cast iron pots, kettles, and Dutch ovens:


Main Page:
The Irreplaceable Cast Iron Skillet


Question & Answer Pages:

Ceramic Top (Flat Top) Electric Range and Cast Iron Pots

Hot Fire for Curing & Cleaning

Iron and Carcinogens in Cast Iron

Misc. Questions & Answers

Pre-Seasoned Cast Iron Pots

Salt for Cleaning Cast Iron

Sanding Cast Iron Pots

Self-Cleaning Oven for Cleaning & Seasoning

Warped or Cracked Cast Iron Pots

Washing Cast Iron Pots


Cast-Iron Pans    Cooking Hints & Tips   

Comments and Reviews

16 Responses to “Iron and Carcinogens in Cast Iron”

  1. samia

    does anyone know about in which form iron absorbed into food and its bioavailibity into blood stream

  2. Erica

    We accidentally left one of those backpack/pouch with strings on top of the cast iron skillet and of course it melted onto it…. will cast iron absorb chemicals? If we manage to clean it out is it safe to use?

  3. Kathy

    Rinse out your cast iron, dry it. Put it in your oven’s self cleaning cycle. All contaminants will burn off. Brush the remnants out and reseason your cast iron per methods prescribed by Cook’s. Use organic flaxseed oil for best result. It is a 6 step process but worth the time and effort.

  4. Anne

    I am also interested in the answer to the question about bioavailability. What is meant by ‘absorption’? And has anyone reported increases in individuals’ iron levels correlating to cooking with iron cookware?? I want to better understand about the absorption of this iron into the foods. Are iron particulates transferred? Is that what’s going on?? I have heard all of these recommendations regarding cooking with cast iron. I have no problems cooking with cast iron and have done so all my life. Yet, I still suffer from low iron levels.

  5. Marissa

    Thanks for the data on how much iron is released with cast iron. While I have already used cast-iron cookware, I was curious how much of dietary iron can come from the cookware. And not about the carcinogen part, never heard of it. It was the reason I switched from Teflon to cast-iron completely. Will do some more research.

  6. Jin

    The amount of iron leached from iron cast cookware from your average everyday cooking is about the same magnitude as recommended daily iron intake. The leached iron is bioavailable however not that much gets absorbed by the body.

    I don’t think one needs to worry about leached iron. Iron cast cookware were used around the world for centuries and the ancient Chinese has benefited from it as a reliable source of dietary iron, with the typical Chinese cooking being plant-based and lacking iron-rich animal products.

    I guess it’s far easier and likely to get iron over-dose by the way of taking too much iron supplement pills, rather than from cooking with iron cast pots and pans! The bit of leached iron that does get absorb is the same iron you get from food.

  7. Katherine Elizabeth Gates

    From the answer given to Gary Hollingshed on 11/28/05. It was discussed that there are free radicals in black pepper, but everywhere I read said that pepper is an antioxidant that fights free radicals.

  8. Dyllan Venezio

    Are there any studies on the differences between iron absorption in a well seasoned pan versus a pan that has not been seasoned?

  9. Asma Sheikh

    Iron that leached from iron cast cookware during cooking is really helpful or mandatory for human body?

  10. Judy Thompson

    I have moderate to severe allergic reactions to excess iron (such as Iron Pills or Molasses) and wonder if I should reduce my use of castiron cookware. I know as we get older some things will bother us more, and would cast iron cookware be likely to make me more sensitive to iron?

  11. Crazy Kitchen

    Thanks for sharing this awesome content.

  12. Carolina Arey

    Thanks for sharing this chart

    Rinse out your cast iron, dry it. Put it in your oven’s self-cleaning cycle. All contaminants will burn off. Brush the remnants out and reseason your cast iron per methods prescribed by Cook’s. Use organic flaxseed oil for best result. It is a 6 step process but worth the time and effort.

  13. Ashley

    Thank you for sharing this important information. I have heard long ago about old pans been harmful and carcinogen, but never knew there is some kind of measurement of how much iron we get from old pans and new ones and etc. I also heard that old one pans from or grannies were more safe… But for now i would rather change pans more often to be sure the surface of it has less scratches so it is more safe for my family.

  14. Barbara V

    Would a layer of parchment paper in a cast iron bread baking vessel block the absorption of iron? My body is unable to rid itself of iron naturally so I have to be very careful of intake.

    • Sandra B.

      I have the same iron issue as Barbara V and was wondering about parchment paper keeping the food (I’m baking bread) from absorbing the iron. I would love to know the answer to this.


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