Guest blog by Vicky Ware
Kitchen Utensils: The Good, the Bad and the Ugly
Our foods come into contact with all sorts of surfaces before we eat them. I’ve had second thoughts when tucking into food that has been prepared in a pan with a missing surface or stirred with slightly melted spatula. If the base of your previously non-stick pan is missing, at some point you’ve probably eaten it.
I’ve taken a look through the evidence to see whether there are any materials used in the kitchen which could be bad for health – silicon, aluminium, plastic, which materials are best for cooking, stirring and storing our food?
First though, it’s time for a dose of perspective.
Chemical Causes Cancer…
The word ‘chemical’ doesn’t mean ‘bad unnatural thing’. A more accurate definition would be ‘thing’! Absolutely everything is made of chemicals, from our food to our bodies. The word chemical is often used to scare people into reading an article; ‘chemical released from cooking utensil’ doesn’t necessarily mean there are any health risks – as we’ll see with soapstone below 1.
Dose is another really key factor when looking at lots of health issues 2. Chemicals which are bad for us at high doses may be good for us at low doses, or not do anything to us at low doses. Dietary iron is a good example – it’s essential for our health but poisonous if we have too much 3.
With this way of thinking about chemicals and doses, stories entitled ‘chemical released from plastic causes cancer’ seem less scary – depending on the source of information. They’re often used as scare tactics to get us to click on an article.
With that information under our belts, let’s take a look at the evidence behind health worries surrounding materials used in the kitchen.
Aluminium cooking utensils may release some aluminium into the food you cook on them. Early studies showed a link between high aluminium levels in drinking water and increased chances of developing Alzheimer’s disease 4;5. People with Alzheimer’s tend to have more aluminium in their brain than people who don’t have the disease but experts don’t know whether getting the disease causes aluminium to build up abnormally or whether the aluminium itself causes the disease 5.
High levels of aluminium exposure may be a health risk, however these are usually only found in occupational settings where people breathe in aluminium dust for years 6.
The Alzheimer’s Association state there is no increased risk between the dose of aluminium you get from using aluminium cooking utensils and your risk of getting the degenerative disease 7, however some experts disagree 8.
Some poor quality aluminium cookware has been found to contain high levels of lead, which then leaches in to food. The World Health Organisation hasn’t been able to establish a safe tolerable limit for lead – the safe limit is probably zero 42. Low level exposure to lead over a lifetime can cause reduced IQ and other neurological problems as well as affecting cardiovascular health 9. It’s unlikely that aluminium cookware bought in the UK contains lead so this shouldn’t be a major concern.
Cast iron is a reactive metal, meaning chemical reactions can occur between acidic foods and the surface of the pan. Cast iron also rusts quite easily, so has to be covered in a layer of fat to prevent rust forming. However, using cast iron pans may up your intake of this essential nutrient.
Cooking eggs in a cast iron pan may double or triple the iron content of the meal 10. If you’re at risk from getting too much dietary iron, it would be best to use other cooking utensils.
Copper pans heat very evenly, which makes them great for cooking food. However, acidic foods can react with the copper causing copper to leach from the surface which could result in copper toxicity although this is rare with modern cooking utensils. Only using pans which don’t have visible corrosion or wearing will help reduce the risk of this 11.
Glass doesn’t leach anything into foods and is also easy to clean meaning it won’t harbour any unwanted bacteria.
Glass is also a great way to store foods from dry foods like oats and rice to leftovers – or even your packed lunch if it’s a stew or soup. Recycling Lucy Bee Coconut Oil jars are great for this – especially the new 1 litre jars.
One of the key chemicals associated with health concerns surrounding plastic are BPAs, which are known to be hormone disruptors – they mimic oestrogen in the body. They are also linked with abnormal development of reproductive organs and women with the highest levels of BPA in their blood have increased chance of miscarriage and of developing problems with their ovaries 12;13. They’re also associated with multiple neurodegenerative disorders and affect our immune systems 14.
Experts are finding it difficult to decide how much BPA we can be exposed to before it becomes a risk to health 15. Although regulatory bodies in Europe and America have deemed BPAs to pose no significant impact on health, the scientific community have questioned this stance 15.
Our bodies can get rid of BPAs quite quickly, the problem is we are constantly exposed to them through food we eat that has been stored in plastic and pretty much anything plastic around you through skin exposure and breathing 16.
Although plastic bottles tend to get a bad rap, studies have found that the levels of BPA they release are very low – the maximum being 1% of the current daily tolerable limit defined by the World Health Organisation 17.
Of greater concern perhaps should be clingfilm which has been found to release a ‘significant’ amount of BPA into foods that come into contact with it. One use of clingfilm isn’t going to do you any harm but if you wrap every piece of food you eat in the stuff you might want to consider other food storage options 18. If you do microwave food covered in clingfilm, it’s important to make sure the film isn’t touching the food.
As of January 2015 the European Union has lowered the daily tolerable limit considered safe for health – while at the same time releasing a statement saying there is no health risk from current levels of exposure to BPA 19.
The problem might not be one product in particular but the fact that we are exposed to constant low levels of BPAs in practically everything we use that is plastic 16.
Phtalates, which I talked about in my skin absorption blog are anther hormone disruptor found in plastic packaging. Long term exposure to pthalates increases blood pressure 20 and also affects hormones. They’re thought to be one of the reasons girls are starting puberty earlier and earlier 21. They’re also linked with asthma and allergies 22.
The World Health Organisation has called for more research to be done on the effect of hormone disruptors such as phthalates on health because they’re worried about the health risks 23. It’s thought that there are probably a lot of endocrine disruptors besides phthalates which are not being tested because companies do not give enough information on what is in their product 23.
The World Health Organisation knows that close to 800 chemicals humans are exposed to are endocrine disruptors, however only a few of these have been tested to check they are safe 24.
Endocrine disrupting chemicals are thought to be risk factors for affecting male and female reproduction, breast development and breast cancer, prostate cancer, thyroid problems, metabolism problems and obesity along with cardiovascular health 25.
Silicon is an inert material, which means it doesn’t really change unless exposed to very high temperatures 26. Silicon cooking implements usually have written on them the temperature they can be safely heated to but most can sustain 360 degrees C safely.
Soapstone cookware is used primary by people in south-east Brazil but it might be worth looking into as leaching of chemicals in from these cooking utensils are a good thing. Research has found that regular use of soapstone can contribute to magnesium, calcium, iron and manganese intake – especially iron 27;28.
Stainless steel pots and pans don’t heat as evenly as thicker pans such as those made from copper and stainless steel so might not be the best choice if you’re a master chef. However you can get versions with copper bases which allow for more even heating without your food being exposed to the copper.
However, studies have shown that stainless steel does leach nickel, chromium and iron into food – the amount depends on how many times the pan has been used (leaching reduces over time) and how the food was cooked 29;30. Chromium and iron are required for health, however nickel has adverse health effects 31;32.
Naturally antibacterial, wood is the perfect material for knife handles, spoons and spatulas. While it might go black if you are absent minded and leave it directly on the heat, it’s not going to release anything dangerous into your food 33.
Some woods contain oils which stop them absorbing tastes – for example olive wood is a great material for chopping boards as it doesn’t absorb strong flavours meaning you can chop your mango on it without having to endure a garlic-flavoured-mango-sorbet.
There have been some health concerns raised about Teflon due to the old manufacturing process which used a chemical called PFOA. Since 2012 PFOA is no longer used to make Teflon coated pans 34.
PFOA is only present in very low levels on Teflon cookware and is more of a risk in the environment at large as it is released from industry into the environment. Some studies have found it is in the blood of just about everyone in the USA 35. The good news is that levels in people’s blood have been going down since 2000, probably due to improved manufacturing methods 35.
Rather than pans, it’s thought that the greatest levels of PFOAs we’re exposed to come from chemicals used to treat carpeting and flooring in our homes 36. Microwavable popcorn bags are thought to be a large source of PFOA and could account for 20% of the PFOA found in an individual who eats only 10 bags a year 37.
Over-heating Teflon cookware can release chemicals which could be a risk to health – therefore it’s important to keep the pan below 260 degrees C 35;34. One study found that as Teflon pans start releasing toxic gases when heated to 240 degrees C and at 360 degrees C they release at least six toxic gases including carcinogens and environmental pollutants 38.
There is no evidence that using Teflon coated cookware at recommended heats is bad for health 39.
Testing for Safety
The UK has strict regulations which all materials designed to come in contact with food have to pass in order to be sold. This means anything bought as a cooking utensil must have passed tests showing that if any chemicals transfer from the utensil to the food it must be within safe limits 40.
As we found when looking into cosmetics in the skin absorption blog, the problem can arise when people are exposed to a chemical or element regularly from lots of different sources 41. Although the dose we receive from one use isn’t going to harm us, a life time being surrounded by plastics might affect our health. This is harder for experts to test since everyone is going to be exposed to different products depending on what they chose to use in their home 41.
Overall, most materials found in the kitchen are fine for their intended tasks. However, there are some which seem to be completely safe and some which have possible health queries. It seems we should be more worried about things we don’t really think about – like plastic kitchen flooring – than things we maybe do consider like storing foods in plastic containers.
The main things I’ll take away from researching this post is to buy high quality cooking utensils – they last a long time and will be used to cook for all the people I care about most (myself included), to not over heat pans when cooking and to reduce my exposure to plastic as much as is possible in this plastic-coated age.
Vicky has a degree in Biological Sciences with a focus on biochemistry and immunology and is currently studying for a MSc in Drug Discovery and Protein Biotechnology. She is also an endurance athlete.
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- Dose, 2014. The dose makes the poison.
- Cabantchik, 2013. The molecular and cellular basis of iron toxicity in Iron Overload (IO) disorders. Diagnostic and therapeutic approaches.
- Rondeau, 2008a. Relation between aluminium concetrations in drinking water and Alzheimer’s disease: an 8-year follow-up study.
- Rondeau, 2008b. Aluminium and silica in drinking water and the risk of Alzheimer’s disease or cognitive decline: findings from 15-year follow-up of the PAQUID cohort
- Science Daily, 2014. Elevated brain aluminium, early onset of Alzheimer’s disease in an individual occupationally exposed to aluminium.
- Alz.org, 2015. Alzheimer’s Myths.
- Exley, 2014. Why industry propaganda and political interference cannot disguise the inevitable role played by human exposure to aluminium in neurodegenerative diseases, including Alzheimer’s disease.
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- Sugiura-Ogasawara, 2005. Exposure to bisphenol A is associated with recurrent miscarriage.
- Takeuchi, 2004. Positive relationship between androgen and the endocrine disruptor, bisphenol A, in normal women and women with ovarian dysfunction.
- Genuis, 2012. Human excretion of bisphenol A: Blood, Urine, and Sweat (BUS) Study.
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- European Food Safety Authority, 2015. No consumer health risk from bisphenol A exposure.
- Trasande, 2013. Urinary phthalates are associated with higher blood pressure in childhood.
- Chen, 2013. Phthalates may promote puberty by increasing kisspeptin activity
- Bornehag, 2004. The Association between Asthma and Allergic Symptoms in Children and Phthalates in House Dust: A Nested Case-Control Study.
- Neira, 2013. Effects of human exposure to hormone-disrupting chemicals examined in landmark UN report.
- Bergman, 2012. Endocrine Disrupting Chemicals, World Health Organisation Report 2012.
- Diamanti-Kandarakis, 2009. Endorcrine-disrupting chemicals. An Endocrine Society scientific statement.
- Food Standards Agency, 2005. Chemical Migration from Silicones Used in Connection with Food Contact Materials and Articles.
- Quintaes, 2002. Soapstone (steatite) cookware as a source of minerals.
- Diego Quintaes, 2011. Soapstone utensils may improve iron status in adult women. A preliminary study.
- Kamerud, 2013. Stainless steel leaches nickel and chromium into foods during cooking.
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- DuPont Guidelines, 2015. Key Safety Questions about Teflon Nonstick Coatings.
- Cancer.org, 2015. Teflon and Perfluorooctanoic Acid (PFOA)
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- Renner, 2006. It’s in the microwave popcorn, not the Teflon pan.
- Seidel, 1991. Chemical, physical and toxicological characterization of fumes produced by heating tetrafluoroethene homopolymre and its copolymers with hexfluoropropene and perfluoro(propyl vinly ether).
- Powley, 2005. Determination of perfluorooctannoic acid (PFOA) extractable from the surface of commercial cookware under simulated cooking conditions by LC/MS/MS.
- Food Standards Agency, 2015. Contaminants and food contact materials: Guidance for businesses.
- Koch, 2009. Human body burdens of chemicals used in plastic manufacture.
- World Health Organisation, 2010. Exposure to Lead: A Major Public Health Concern.
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