Peat Safe Cookware?

Dave Clark

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how about just plain cast iron?
I think the general knowledge is that the cast iron will emit a fair amount of inorganic iron into the food especially if cooking an acidic food, i.e. tomatoes,vinegar, citrus, etc.. This type of iron is similar to the enriched iron put into grain products, etc. and is not considered healthy. I suppose occasional use would be okay, but most would caution cooking with cast iron everyday, that's my understanding.
 
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@Dave Clark
How about enameled type cast iron whats your take?

so for everyday use its better to use stainless steel or the trending now ceramic pans?

@LiveWire

I meant the lodge/tramontina type cast iron without the enamel.
 

Dave Clark

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@Dave Clark
How about enameled type cast iron whats your take?

so for everyday use its better to use stainless steel or the trending now ceramic pans?

@LiveWire

I meant the lodge/tramontina type cast iron without the enamel.
Ceramic or enamel coated cast iron would be fine.......but, get a good quality type, there are reports of the cheaper stuff having lead or other contaminants in the enamel. I can;t tell you off the top of my head which brand would be good, but make sure you do a thorough search on which brand meets safety and non-toxic requirements. Stainless steel is not bad if it is a type that you can hold a magnet to, that shows that there is low levels of nickel and other alloys in the metal that can leach out when cooking. There are a lot of new type cookwares with copper and titanium, etc. but I don't think enough testing was done to see what, if any, metal leaches out when cooking. Buyer beware.
 
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@Dave Clark

thanks dave. I saw the crock pot brand, enameled color white inside the cookware. Ill search for information online if its safe but i read somewhere to get the white colored enameled. Ill try to find where i read but i remember that if its white is safe because of the glaze that was use?
 

GgOTi

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Would a potentially good middle ground be to season some 18/0 stainless steel? The layer of seasoning should behave in a similar fashion to how it does with seasoned cast iron, no? It would help prevent moisture from corroding the cookware and help to reduce metal from leaching into food.

Also, for those interested in sticking to nickel free stainless steel, this series of cookware may be worth looking into.

https://www.amazon.com/Chantal-SLIN-2024-Induction-Stainless-10-inch/dp/B00HXC7U9M?th=1
 
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Dave Clark

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Would a potentially good middle ground be to season some 18/0 stainless steel? The layer of seasoning should behave in a similar fashion to how it does with seasoned cast iron, no? It would help prevent moisture from corroding the cookware and help to reduce metal from leaching into food.

Also, for those interested in sticking to nickel free stainless steel, this series of cookware may be worth looking into.

https://www.amazon.com/Chantal-SLIN-2024-Induction-Stainless-10-inch/dp/B00HXC7U9M?th=1
This looks good in terms of the nickel. Just when we buy it we will find out that the titanium and chromium leaches out and is toxic, lol! Wondering if anything in terms of cookware is completely safe.
 

Inaut

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It's funny, on the most recent OneRadio Network interview with Ray Peat, Patrick mentioned how he uses Vision glass (orning) that he purchased off eBay. When I move out of the place I'm in, I'll probably buy a set.
 

Dave Clark

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It's funny, on the most recent OneRadio Network interview with Ray Peat, Patrick mentioned how he uses Vision glass (orning) that he purchased off eBay. When I move out of the place I'm in, I'll probably buy a set.
I know it has been talked about before on this forum, but be careful with Visions, I don't know if they improved it or not, but years ago I had a Visions casserole dish explode on the stove. I was a few feet away thankfully, and didn't get any shrapnel. I can tell you that when you experience that scenario first hand, you think twice before getting that cookware again. Just thought I would mention it again.
 

Amazoniac

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I searched the whole internet to find the answer to this, as surprisingly, nobody here gives the full answer. Finally I found it, so I thought I'd come back here and post my findings.

First of all, Peat's information to buy stainless steel that sticks with a magnet is nothing but provacative and is frustratingly uninformative. 18/10 (300 series) and 18/0 (400 series) cookware both stick to magnets (they're made that way to work on induction cooktops), however the 400 series sticks much stronger because of the lack of nickel. Because of Peat's concern for nickel, you'd assume he means to get the 400 series, which has 0% nickel, instead of the 300 series, which is 10% nickel. However, after significant research, I'd get the 300 over the 400.

Here's what you need to know:
Probably the safest cookware isn't Stainless Steel- it's enameled cast iron. Enameled Cast Iron is perfectly safe as long as the interior of the dish is white - the lack of color very likely indicating a lack of lead in the enamal (colored enamels more often have lead). Le Creuset makes a model but it's super expensive. The Lodge makes one that's nearly as good at 1/6 the price. http://www.amazon.com/Lodge-EC6D43-Enam ... ql_qh_dp_t

Second best option is Stainless Steel. Obviously you can't buy the cheapo 200 series, which releases a bunch of metal. So you're left choosing between the 300 (18/10) and 400 (18/0) series. The 400 series can have as low as >1% Nickel, which sounds like a great option. But here's the problem... it's much more corrosive than the 300 series, and although there's no nickel to leach in the 400 series, it has higher total release rates of metal than the 300 series, with the vast majority of the release being iron. (This info can be found in page 30 of the study provided in the forthcoming link.) Lastly, it's very hard to find pans that are 18/0 on the exterior and interior. Typically they'll be 18/0 on the exterior (for induction) and 18/10 on the interior. The only one I found that MIGHT be 18/0 on the inside and out is the Farberware Millenium Set, but honestly I don't care. A good quality 300 series (like All-Clad) is a better option. Once the sets are scratched, pitted, corroded and damaged, the release rates of metals is much higher. A quality 300 series set could last multiple lifetimes with little wear. The 400 series isn't likely to last 10 years without damage.

The remainder of my response is lifted from the comments section of gnowfglins.com's article on The Scoop on Stainless Steel Cookware, written by user Holly Gates. It sums it all up nicely:

300 series stainless is generally speaking more corrosion resistant than 400 series, meaning that less of the metal would get into your food).

Here is a very pertinent survey conducted by the government of Finland in 2010:

http://www.ttl.fi/en/publications/elect ... _steel.pdf

The study, titled “Review on Toxicity of Stainless Steel” is 87 pages long, with several dense pages of references at the end. For each potential area of concern with stainless affecting human health in every situations, the findings of numerous scientific studies are assessed and evaluated in light of EU guidelines for toxic material exposure. Whether or not you put any stock in the EU guidelines, the amounts and types of material which are found to transfer from stainless to food are interesting to think about.

As pointed out by others here, the main constituents of the stainless steels used in foodware are (300 and 400 series) are iron, nickel, and chromium. The materials of potential concern would be the nickel and chromium. In these alloys, the availability of nickel is found to be less than 0.1% of what it would be from a similar proportion of bulk nickel metal. The exception is alloy variants with sulfur added, typically to enhance machinability. These are not used for foodware. Even people hypersensitive to nickel (i.e. skin allergy) experience no reaction from intimate and lengthy contact with 304 or 316 stainless.

The availability of chromium however is approximately equal to what would be predicted given its proportion of the alloy. The question is how much chromium is coming off the metal during typical food preparation and storage activities.

The Finnish report finds that for medium to high pH range, even at cooking temperatures and with prolonged storage, essentially nothing transfers from the stainless to the food. Low pH materials result in some transfer.

One study cited in the report looked at storage of pickled lemon in stainless, which is lower pH than almost anything else you would think of using in the kitchen (pH 2.1). Kombucha is 3-4, pure white vinegar is 2.4. Other studies looked at prolonged boiling of low-ish ph foods in stainless. What was generally the result was that while some chromium and nickel transferred to the food, the actual amount was something like 10 times less than typical intake of these metals from the food itself (25ug/kg food is typical).

Exceptions are with the first few uses of new pots, and with some types of welds.

Many surgical implants and medical devices are made from 316L. This is because it is among the least reactive materials with biological systems that can be produced and worked at a reasonable cost.

To me, knowing that my food itself contains 10x the amount of what is coming off my pot makes me feel quite comfortable with the safety of my 304 stainless.

------

I hope this lays this issue to bed once and for all. For those of you wondering, here's the set I wound up purchasing: http://www.amazon.com/gp/product/B00421 ... UTF8&psc=1
- Release of nickel and chromium in common foods during cooking in 18/10 (grade 316) stainless steel pots

"[..]our study aimed to reproduce the worst possible scenario for Ni-allergic and/or Cr-allergic patients in an everyday domestic setting that can be considered to be common for many people, even in different nations. As there is general agreement in the literature that acid pH increases metal release from stainless steel (4, 6–11, 13), tomato and lemon were chosen because they are two of the most acidic foods that are commonly used in many cultures and in large areas of the world. Cooking procedures were also defined by keeping in mind that the amount of time dedicated to food preparation is nowadays relatively limited, particularly in urban contexts, and is significantly reduced in comparison with past decades (14, 15). Finally, in a typical domestic environment, a pot remains in use for several years, to cook different types of foods, and undergoes many cleaning cycles with a mixture of more and less aggressive procedures. These conditions are very difficult to reproduce in a laboratory setting, with a necessarily limited number of cooking and cleaning cycles: for such reasons, pots that had been subjected to domestic use for years were used in addition to new ones."

"Three commercial grade 316 stainless steel pots (18/10 steel, i.e. steel containing 18% Cr and 10% Ni) produced by manufacturers from different countries, used in a domestic setting for 10–12 years, and three unused pots identical to the above ones were chosen for cooking procedures. The stainless steel grade was engraved on each pot. Between procedures, all pots were washed with tap water and a common dishware detergent, reproducing the home scenario."

"Experiments were performed with tomato sauce (TS) and lemon marmalade (LM), two foods that are regularly consumed by many populations worldwide. Additionally, these foods are acid, and low pH is associated, according to the literature, with increased release of metals from stainless steel (6–9): thus, our choice was aimed at evaluating the maximum release that may occur in everyday conditions. In the first case, 750 ml of commercial TS was mixed with 50 ml of water before cooking; in the other case, 500 g of lemon pulp was mixed with 300 g of sugar to prepare an LM. The two preparations (pH 4.5 and 2.6, respectively) were cooked in each of the pots used, with a lid, for 60 min, mixing with a spoon every 10min. Five 5-ml aliquots were withdrawn at 0, 15, 30, 45 and 60 min."

"[..]an acid (citric acid 0.1 M in water, pH 2.3), a saline (NaCl 0.06 M inwater, pH 7.7) and a basic (NaOH 3 μM in water, pH 9) solution (1 l each) were [also] prepared and boiled in the pots for 60 min, and five aliquots were obtained at 15-min intervals."​

"In our experiments, the maximum amounts of Ni and Cr released by 18/10 (grade 316) stainless steel during food preparation were 0.144 and 0.098 mg/l, respectively, in TS, and 0.077 and 0.074 mg/l, respectively, in LM."

upload_2020-8-19_21-21-20.png

"In other words, the amounts of Ni and Cr in a standard portion of 126 g of TS – as defined by Kamerud et al. (4) – would increase by up to 18.1 and 12.3 μg, respectively, as a result of 1 h of cooking in stainless steel pots under ordinary domestic conditions; in a portion of LM (∼35 g), the additional amounts of metals following cooking would be approximately up to 2.7 μg of Ni and 2.6 μg of Cr. These values are below the limits reported in the literature as the lowest critical thresholds for elicitation of allergic reactions, which are 67 and 2500 μg for Ni and Cr, respectively (4)."

"There is general agreement in the literature on higher metal release from stainless steel pots at first use, with significant reductions being seen after a few cooking cycles, but the amounts reported by various authors are different (4, 6). Our results confirm the above trend, but suggest that the release at first use is below critical limits."

upload_2020-8-19_21-21-25.png

"They also differ remarkably from those reported in some of the previous studies. Early articles, dating back to the end of the 1970s, reported significant increases in the amounts of Ni and Cr in acidic foods cooked in stainless steel utensils (8, 10); later, in 1992, Kuligowski and Halperin not only confirmed such data, but even suggested that Ni-sensitive patients should avoid the use of stainless steel containers for food preparation, and that the cookware industry should consider switching to a non-Ni formulation (9)."

"In 2013, Kamerud et al. (4) reported significant release of metals from stainless steel pots, even if used for several cooking cycles. In particular, the authors suggested that the amount of Ni released into an ordinary serving of TS can be up to 88 μg, which is more than four times higher than in our study, and exceeds the minimum level required to elicit allergic cutaneous reactions, even without considering the Ni content of the food itself. Concerning Cr, the amount released into the same serving of sauce would be 86 μg, which is largely insufficient to cause allergic reactions, but is still over six times more than in our experiments. The contrast with our data is particularly evident and surprising in the case of this latter study; the different experimental setting might be a possible explanation. In the majority of their tests, Kamerud et al. (4) cooked TS in polyethylene tubes, adding stainless steel chips, and this obviously does not reproduce what commonly happens during food preparation. Moreover, the types of steel used for such procedures are different from those of our pots, and this could influence metal release in specific conditions. Last but not least, the minimum cooking time was 2 h, a time that often does not correspond to real-life conditions. Only one experiment was performed by Kamerud et al. with a commercial saucepan, made of grade 316 steel, but the cooking time was 20 h, which is definitely too long to be considered ordinary."

"Conversely, our data agree with those reported by Kumar et al. in 1994 (7), Flint and Packirisamy in 1997 (6), and Accominotti et al. in 1998 (5), which suggest limited release of metals during cooking procedures."

"Regarding procedures, foods and conditions that can be regarded as ordinary for a large part of the population, the amounts of Ni and Cr released from 18/10 (grade 316) stainless steel during cooking are insufficient to induce reactions in allergic subjects. For both metals, the daily intake mainly depends on the amounts naturally contained in foods, and recommendations for patients should be more focused on a correct dietary regimen."


"Leached Ni can, however, be relevant for highly sensitive patients, who can react even to a dose of only 67 μg. In that case, the amount of 14–17 μg per 100 g of food detected in some of our experiments could, even in the context of a low-Ni diet, exceed the individual critical level. Additionally, literature suggests that immunological tolerance to nickel can be induced by oral low dose exposure (18, 19). In such a context, the relatively small quantity of Ni leached from stainless steel pots might have significant importance, and should be kept into account when daily Ni intake is calculated. Although it appears exaggerated to suggest avoidance of 18/10 stainless steel cookware to all patients who are allergic to Ni, it is certainly advisable to perform careful testing and establish close collaboration between physicians and patients, to define proper personalized prevention measures."​

- Beneficial Effects of a Low-Nickel Diet on Relapsing IBS-Like and Extraintestinal Symptoms of Celiac Patients during a Proper Gluten-Free Diet: Nickel Allergic Contact Mucositis in Suspected Non-Responsive Celiac Disease
 
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Amazoniac

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Amazoniac

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- Speciation of Nickel

"The main route of nickel intake for nonoccupationally exposed humans is dietary ingestion of food and drinking water (Table 2.14.1). In most food products, the nickel content is less than 0.5 mg kg−1 fresh weight. Cacao products and nuts may, however, contain as much as 10 and 3 mg kg−1, respectively [45]. Several studies are dealing with nickel contamination of food products by cooking utensils and packing materials. Stainless steel pans and pots show only a small release of nickel to the cooking food even when the most aggressive (acidic) foods are prepared [46–48]. The values for nickel uptake were negligible under human health considerations so that the European Commission concluded in their report that nickel-sensitized persons who suffer from allergy gain no advantage by avoiding uncorroded stainless steel utensils [49]. Another study demonstrated that coffee machines also did not release nickel in quantities of any significance while on the contrary 10 out of 26 commercial available electric kettles released more than 50 μg L−1 nickel to water [50]. An earlier study shows higher nickel concentrations in canned vegetables, sugars and preserves, bread and cereals in comparison to other food groups, suggesting a contribution from food processing equipment, and possibly, food cans [51]. Diet studies indicate a total average oral nickel intake of 0.2–0.3 mg/day [4], with an absorption rate of less than 15% from the gastrointestinal tract [52]. The quantity of nickel absorbed depends on the nickel bioavailability and thus on the nickel species and nickel content in the food, wherein the Ni2+ cation is considered as the most bioavailable species."

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"Although dietary intake is the most important route for nickel exposure, information on nickel speciation in foodstuffs is rather scarce. The very few speciation studies concern mainly tea, soybeans and human milk. Nickel in black tea leaves was classified as a highly extractable element that is present as complexes with large organic molecules [53]. Organic nickel complexes in Kenyan and Indian black teas as well as Chinese green tea were found primarily associated with the flavanoid components [54]. However, the main part of nickel in tea infusions appears to be present in the cationic form as Ni2+, besides large organic nickel complexes in the size range of 4–6 kDa [55]. In soybean flour, 66% of the total nickel was extractable and was present mainly as complexes of 2–3 kDa size [56]. Also, in human milk, nickel was found to be associated with high molecular mass biomolecules, probably caseins, lactotransferrin, serum albumin or immunoglobulins [57]. The edible biopolymer arabinogalactan, extracted from the leaves of the Brazilian plant Pereskia aculeata and proposed as a food additive, was found to be a ligand for nickel. The molecule has a tridimensional web structure, where Ni2+ is complexed by galacturonic groups [58]."

"After absorption, the nickel is distributed in the body by the blood. The main carrier protein of nickel in serum is albumin, but nickel can also be bound to α-2 macroglobulin and histidine [73]. Reference values for nickel concentrations in serum and urine from healthy persons without occupational exposure to nickel compounds have recently been compiled [73, 74]. Values for serum/plasma are in the range 0.14–0.65 μg L−1; values of around 0.2 μg L−1 seem to be the most reliable. Corresponding values for urine are 0.9–4.1 μg L−1, with values of 1–2 μg L−1 the most reliable. For whole blood, values of 0.34–1.4 μg L−1 are given."

"On average, the body of adult humans contains about 0.5 mg nickel per 70 kg. The highest concentrations of nickel are found in the lung and in the thyroid and adrenal glands (about 20–25 μg kg−1 wet weight). Most other organs (e.g. kidney, liver, brain) contain about 8–10 μg kg−1 wet weight [75]."

"Nickel may undergo redox metabolism generating the trivalent form and thus forming reactive oxygen species. The intracellular release of nickel ion following phagocytosis of particles of oxidic and/or sulfidic nickel is an important metabolic pathway. Minute particles containing nickel have been found close to the nuclear membrane. Nickel ions may also enter the cell directly, although possible transport mechanisms are unclear."

"Absorbed nickel is predominantly extracted by the kidneys and eliminated in the urine [76]. Excretion via sweat, secretion via saliva and deposition in hair has been reported [77]. However, urinary excretion is the main clearance route. The biological half-time of nickel depends on the nickel species tested. For soluble compounds, the half-time of plasma nickel is 11–39 hours in humans; for particulate compounds, half-times of 30–54 hours have been recorded [78]. A urinary elimination half-time of 17–48 hours has been reported for the absorbed dose following experimental oral exposure in humans [52]. Nickel particles in nasal tissue and lungs can have a halftime of 3.5 years [79], while nickel was found in respiratory tissue of nickel refinery workers even more than 20 years after exposure. These particles were identified as trevorite, an insoluble, spinel-type mineral, which is probably biologically inert [80]."

- Concise Review of Nickel Human Health Toxicology and Ecotoxicology
 
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