The Skinny on Safe Cookware
Chances are that you know that aluminum and non-stick cookware have been deemed to be toxic. But what are the alternatives? In this post, I will update you on my research into what might be considered safe cookware. It turns out that what might be considered safe cookware is not so straightforward. And I have some unanswered questions, which I am hoping you, my readers, can help answer, and possibly even motivate companies to be more transparent and share the actual test reports of their cookware.
Safe Cookware: Stainless Steel Cookware
Stainless steel looks safe, and has earned a reputation as being safe. But how safe is it? Stainless Steel leaches chromium, nickel, and iron into food during cooking. While iron and chromium are essential nutrients for which stainless steel may be useful, nickel is not needed for our health.
This study determined that the amounts of chromium and nickel significantly increase with longer cooking times, with the use of new cookware, and with cooking tomato sauce. While generally these amounts are under the Tolerable Upper Intake Levels, some people may have adverse reactions such as dermatitis even when the exposure amounts are under the established tolerable upper intake levels.
I use a big stainless steel pot for making beef bone broth that I cook for over 36 hours. And I drink the broth almost daily. A recent heavy metal test, which shows how much if any heavy metals my body has accumulated over time, shows that I do have some nickel, but it is within the safe level.
Stainless Steel Cookware We Use
All-Clad. Pan and pots are made in the US. The accessories and tea kettles are made in China.
Safe Cookware: Cast Iron Cookware
Cast iron leaches iron into food during cooking. Iron is an essential nutrient; however, in this case, you can get too much of a good thing: iron overdose is toxic. Like with stainless steel safe cookware, acidic foods, high moisture content, and long durations of cooking increase the release of iron significantly. Studies show that the amount of iron varies from 1.7 mg per 100 g to 26 mg per 100 g, while the upper intake level for pregnant women, those who need iron the most, is 27 mg. So if you cook tomato sauce for long period of time, it is possible to overdose on iron. There is an inexpensive blood test to take to determine your iron level. For more information, check my post here.
My recommendation is to use cast iron for pancakes, bacon and hamburgers, and frying eggs and hash browns. If you’re curious how well cast iron works for frying an egg, see my video, here. It works like a charm. I’m sure it has more uses, but we do not use it as a staple when cooking because of the iron content issue.
Cast Iron Cookware We Use
Lodge. Made in the USA. We use it for frying eggs, hash browns, and making pancakes – things that I can’t do with other safe cookware.
Safe Cookware: Enameled Cast Iron
Le Creuset is a major producer of enamel-coated cast iron cookware. Le Creuset manufactures its cast iron cookware in France. I asked them what their enamel is made of. They informed me that the enamel contains nitrates, potash, agile, aluminate, bentonite, and clay. The enamels outside and inside are fired at 790 Celsius. The melting point of metals is below that, which makes the enamel inert.
I also addressed my concern of lead and cadmium. Good news! La Creuset emailed me a letter confirming that their enameled cast products are tested to California Proposition 65 standards for lead and cadmium and are found to be in compliance. The California Proposition 65 test is the most stringent test available to consumers. It requires companies to have a warning label on products when the amount of toxic substances they contain exceed certain levels. In this case if more than 0.1 micrograms per milliliter of lead or 0.049 micrograms per milliliter of cadmium leached into a 4% acetic acid solution (which is the standard used for the Proposition 65 test), Le Creuset would have to attach a warning label.
Also, Le Creuset stated that there might be traces of lead or cadmium in the exterior enamel. The two colors that do not contain any lead or cadmium are palm and dune. We own a red one, which I bought long before I started doing this research. If you own one already, keep it. But if you are in the market for a new dutch oven, go for palm or dune colors.
Safe Cookware: Slow Cookers
Slow cookers usually have ceramic inserts (unless you want to pay big, big bucks for commercial grade slow cookers). Ceramic slow cooker inserts may contain lead, either because lead is added or because it comes with raw materials used to make the ceramic cookware.
I talked to KitchenAid and they assured me their ceramic has very small amounts of lead – below the FDA’s limit – and that the protective glaze does not have any lead, which is re-assuring to some extent. They would not say how much and would not provide anything in writing. I keep heavy metals under scrutiny because they are bio-accumulative and persistent. In other words, once ingested, they accumulate and stay in the body for a long time.
We use Cuisinart’s slow cooker. Cuisinart assured me there is no lead or cadmium in their slow cooker inserts. However, they admit that they do not test for lead or cadmium because they know they do not add them, which did not sound very reassuring to me, because these metals are contaminants, and so the ceramic inserts may contain heavy metals. Also, Amazon has a link to Proposition 65, which means that the slower cooker might “contain[s] chemicals known to the state of California to cause cancer and birth defects or other reproductive harm if those products expose consumers to such chemicals above certain threshold levels.”
Cuisinart would not disclose what is in the glaze they use, which is not terribly confidence-inspiring.
Unfortunately, our slow cooker broke shortly after this research and I do not have a replacement for it yet. With what I know now, I am looking for a slow cooker manufacturer who can provide a copy of a test report that shows that the lead and cadmium levels are below those set by California Proposition 65. This is what you should be asking too if you are in the market for a slow cooker. Share in the comments what you have found.
Safe Cookware: Ceramic Cookware
Xtrema cookware makes ceramic cookware that they claim is free of lead and cadmium. It is the only ceramic cookware I know of that you can use on the stove top. Unfortunately, they do not fully disclose the ingredients of their ceramic so we would have to rely on their word.
As it turned out Dr. Mercola sells the same cookware under his brand name. His company representative sent me a list of ingredients, which include silicon dioxide, aluminum oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, titanium dioxide, zirconium oxide, cobalt oxide, chrome oxide, nickel oxide, and lithium oxide.
These minerals are fired at 2500ºF, which is way above melting points of all this minerals. For example, the melting point for aluminum is 1,227ºF. This is probably how this cookware is inert and leaching of any metals is extremely small. On the Dr. Mercola website, it states that leaching of aluminum is 0.01, although it doesn’t specify the units. Assuming it refers to micrograms, this seems insignificant to me (http://cookware.mercola.com/ceramic-cookware.aspx).
Xtrema cookware is in compliance with stringent California Proposition 65 limits for accessible lead and cadmium. In fact Dr. Mercola sent me the actual test report that showed leachable lead and cadmium into 4% acetic acid. The California Proposition 65 limit for this type of cookware is 0.1 microgram per milliliter of lead and 0.049 microgram per milliliter of cadmium. The test report shows less than 0.05 for lead and 0.01 for cadmium respectively, which is pretty good.
Keep in mind that Xtrema is not non-stick and you have to be careful with it since it is ceramic after all.
We use Xtrema cookware as a tool in our struggle to reduce our exposure to toxins. We own two pieces.
Safe Cookware: Glass Cookware
Pyrex glass cookware is the major glassware brand made by World Kitchen. There are different types of glasses and Pyrex glass is a tempered soda lime glass. Before 1998, Pyrex was made of borosilicate glass by Corning. European Pyrex called Pyroflam is still made of borosilicate glass, which is more heat resistant. However, when it is dropped instead of breaking into pieces, it shatters into tiny particles.
I called and emailed Pyrex and, unfortunately, they do not disclose the materials with which their soda lime glass is made. They recommended searching on the Internet, which I did and my blog came up (which I found extremely illuminating) (just kidding, kind of).
According to Wikipedia, borosilicate Pyrex is composed of (as percentage of weight): 4.0% boron, 54.0% oxygen, 2.8% sodium, 1.1% aluminum, 37.7% silicon, and 0.3% potassium. And according to Wikipedia also, “soda-lime glass is prepared by melting the raw materials, such as sodium carbonate (soda), lime, dolomite, silicon dioxide(silica), aluminium oxide (alumina), and small quantities of fining agents (e.g., sodium sulfate, sodium chloride) in a glass furnace at temperatures locally up to 1675 °C.”
As you might have noticed, both types of glasses contain small amounts of aluminum. I do not have much information on how much aluminum leaches into food. I found two studies here and here that pointed to the fact that aluminum can leach out into the content. I wish I could hear from the maker of Pyrex themselves about the composition of Pyrex glass and what I may be leaching.
In the meantime, I am not super concerned about the possibility of alumimum leaching. I have a feeling if there is any leaching, the amounts should be minimal. Unlike lead that has no safe amounts, our bodies can tolerate bigger amounts of aluminum before it becomes toxic. I have recently had a heavy metal test done and no aluminum was found in my body, while we use Pyrex all the time.
On the bright side, glass is not known to contain lead unless it is leaded crystal, which soda lime or borosilicate glass is not.
All in all, considering the alternatives, I think glass is one of the safest cookware to use. It is considered the gold standard being inert.
Be careful when you use glass cookware though. After World Kitchen switched to making Pyrex with soda lime glass, there are reports of glass containers breaking. It is glass after all. Do not subject it to drastic temperature changes and follow the manufacturer’s instructions. We use Pyrex all the time – some we bought before 1998 and some after, and have not had many breakages. Knock wood.
Safe Cookware: Carbon Steel Cookware
Carbon steel is commonly used for woks. There are virtually no studies done on the health effects of leaching elements from carbon steel. Carbon steel is an alloy consisting mainly of iron and small percentages of other elements such as carbon, manganese 1.65, silicon 0.60, copper 0.60. Copper and manganese are essential for good health in small doses, and silicon and carbon are part of our body compositions. Considering that carbon steel has small percentages of them, I do not think we should worry about them too much.
The main concern here is iron, which is essential to our health but can become toxic when the body is overloaded with it. But iron leaching is great if you have anemia. For more information on how much iron is too much, read my post here. Unless you have hemochromatosis, I believe carbon steel is a good tool to use for stir frying.
Carbon Steel Cookware We Use
In conclusion, while there are safe cookware options out there, there remain concerns and unanswered questions about each type of safe cookware. I recommend using a balance of stainless steel, cast iron and ceramic, in order to avoid the issues associated with any of the methods, and because different platforms are better for cooking different types of foods.