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Home » Food, Life in Holland » Reheating Spinach Dangerous in Holland, Fine in Rest of World

Reheating Spinach Dangerous in Holland, Fine in Rest of World


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Posted on Monday, May 11th, 2009 at 10:51 am CET

(Please note: I am not a food expert or toxicologist. Please do your own research or consult an expert before making a decision about reheating spinach. Nitrates caused by reheating spinach should be avoided by infants of up to 6 months!)

When my parents were visiting us here in Illinois last week, we had made some spinach-artichoke dip and were about to put the leftovers in the fridge when my mom told me that you can never ever keep spinach leftovers as reheating spinach is dangerous and causes cancer. I vaguely remembered something about this from my Dutch youth, but my American wife and her parents had never heard of such a thing. To be safe we threw the spinach away, but it did make me curious.

It turns out that it is a myth and reheating spinach is perfectly fine. It is true that reheating it many times can cause the formation of nitrites. These should be avoided by infants of up to 6 months, but the risks are negligible for adults.

What is funny, though, is that I could not find any English websites about the danger, but there are countless Dutch sites about it! Apparently, the life-threatening danger of spinach is only known to Dutch people.

Actually, the urban legend seems to be localized in the Netherlands, Indonesia (not surprisingly, as it is an old Dutch colony) as well as Germany and Switzerland. I’ve been reading some funny stories on several blogs from non-Dutch people being told by their Dutch friends that they shouldn’t have reheated the spinach.

On an episode of the British TV show Ready Steady Cook on the BBC, a Dutch viewer sent in a question stating that “as everyone knows one should never reheat spinach”, but she asked whether spinach soup was okay. The three British chefs were surprised by the statement about not reheating spinach. They had never heard of such nonsense.

I wonder how this myth got started in the Netherlands and why people are still believing it, even though most of the rest of the world doesn’t. The website of Iglo, a major spinach brand in the Netherlands, says that reheating spinach is no problem, but they still maintain that you shouldn’t keep it in your fridge for more than 2 days:

Vroeger was het opnieuw opwarmen van spinazie taboe. Zo zou er – net als bij andijvie en spitskool – te veel nitriet vrijkomen, wat schadelijk kan zijn voor de gezondheid. Uit onderzoek blijkt dat de toename van nitriet bij het opnieuw opwarmen van deze groenten meevalt. Hierbij is wel belangrijk dat de groenten snel worden afgekoeld en niet te lang in de koelkast worden bewaard (maximaal twee dagen). De spinazie van Iglo voldoet aan alle wettelijke normen voor nitraat. Doordat Iglo de spinazie direct na de oogst blancheert en invriest, wordt de vorming van enzymen stilgelegd en de vorming van nitriet tegengegaan. Daarom kunt u de spinazie van Iglo zonder problemen opwarmen. (Source: Iglo)

Toxic spinach

Comments

May 27, 2009
1:42 pm
#1 Karin Cooper-de Ruiter wrote:

Thank you for this. Being Dutch myself I remember growing up with exactly the same instructions. When I went on a Food Hygiene course a few months ago here in the UK I put this question to the course leader and she had never heard of it either. Tonight we had ‘spinazie stampot’ and my leftovers have gone in the freezer ready for another time!

Jun 28, 2009
1:59 am
#2 Irene wrote:

Hi & thanks for this.
Raised in Holland with the same myth and now immigrated to New Zealand where everyone seem to have no problem with reheating spinach! After having “advised” a couple of kiwi friends not to reheat spinach I went online and found your post on this. Better get back to them and to all the dutchies I know and tell them the truth, makes life easier too.
Irene

Oct 31, 2009
12:32 pm
#3 Daniel wrote:

Same, same. German myself and raised with the same myth. Glad I could enjoy yesterdays leftovers without a fear of my imminent demise. Thanks.

Nov 1, 2009
1:29 pm
#4 givi wrote:

erg interessant, dit.
i was always under the impression (aka, upbringing) that you couldn’t microwave any leafy vegetables, but could reheat them on the stove just fine; something to do with the radioactive particles speeding up the nitrite process. i think i’ll keep to those guidelines, just in case 🙂

Nov 25, 2009
12:33 am
#5 James wrote:

My Spanish wife is horrified when I attempt to reheat spinach, so I guess it’s not just the Dutch.

Jan 15, 2010
11:49 am
#6 Jeanette wrote:

I’m in Montreal now, eating reheated spinach. I always suspected it to be an urban legend, but as everyone in The Netherlands seems to believe it, I followed the Dutch advice. However as people here apparently also have never heard about it, I figured my suspections had been right. Thanks for this story!

Feb 13, 2010
5:18 pm
#7 caspar wijnberg wrote:

HA, This is so funny! I live in Serbia and My Serbian wife had never heard of reheating spinach being unhealthy.. I am Originaly Dutch so grew up with the believe that there are dangerous chemicals in reheated spinach.. i googled the issue and first hit was this blog.. and it’s exactly what i was looking for.. what a waist of the countless delicious spinach dishes i have thrown out in my life.. what a waist!

Feb 26, 2010
6:21 am
#8 miguel wrote:

The EU Food Information Council advises that reheating is not advisable
http://www.eufic.org/page/en/faqid/unhealthy-reheat-spinach/

Mar 18, 2010
5:25 am
#9 Helga wrote:

How funny! Have been running into the same issues myself. Glad to know I can make spinach soup in bulk and enjoy it whenever 😉

Mar 20, 2010
7:34 am
#10 Grace wrote:

Thanx for the enlightment. Being Indonesian, I grew up with that myth. Reading your article make me realize not only that reheating spinach is a myth, but there might be more myths we believe in were originally came from the Dutch. Well, I wish they inherit us more goods than bads. Thanx again for making up with this one 🙂

Apr 3, 2010
5:20 pm
#11 Petra wrote:

Thanks for posting this! I grew up being taught never ever to re heat Spinach (Germany) and now am asking myself the same thing, because none of my US friends and family had ever heard of this! Glad you researched it!

Apr 24, 2010
2:33 pm
#12 Suzi wrote:

Thanks! Only today in a Bulgarian food forum I read that you should not reheat spinach soup – and I always had before.. So I googled for more info, and was relieved to read it’s OK!

Jul 21, 2010
1:02 pm
#13 Florian wrote:

Oh, now that you guys all say it’s ok to eat reheated spinach I am so relieved. I will just discard what everybody in those non-english-speaking countries says. I am going to eat tons of reheated spinach tonight, and feed my 6 month and 1 day old baby reheated spinach. Maybe we will have that all week long, because it’s so healthy and no problem. And didn’t some sailor eat spinach because it contained so much iron and it gave him huuuge muscles? Was that reheated as well?

I think I am going to google for websites now that tell me how healthy smoking is. After all, I know people who smoked all their life and they are still fine at age 86. Isn’t that proof enough?

Now without the irony – read the text under Miguel’s link thoroughly, don’t just skim through it. It doesn’t say reheated spinach will make you keel over instantly, but it simply recommends caution, alongside with some chemically founded reasoning.

Here is the text from Miguel’s link:

Spinach and other leafy vegetables contain high concentrations of nitrate. The amount depends on the variety, season, and the soil and water conditions where the vegetable was grown. Nitrate itself is totally harmless, but it can be converted to nitrites, and then to nitrosamines, some of which are known to be carcinogenic. Enzymes present in bacteria convert nitrate to nitrite. This happens especially when spinach is heated, stored and then later reheated. Nitrite itself is a harmless compound, but it should be avoided by infants of up to 6 months. It can affect the ability of the blood to transport oxygen by transforming haemoglobin, the protein that carries oxygen in the blood, into methaemoglobin, a form of the protein which is unable to carry oxygen. This can be dangerous for babies and is commonly known as “Blue Baby Syndrome”. However, in view of the fact that acidic conditions favour the formation of nitrosamines from nitrite, coupled with the facts that nearly all foods contain some protein and are exposed to acid in the stomach nitrosamine production cannot completely be prevented. Hence the recommendation to avoid reheating spinach.

Aug 10, 2010
7:11 am
#14 Isabelle wrote:

Well, I think this myth comes from the time when most people cooked food in (not best quality) aluminium pots, because the aluminium and the nitrite would give a chemical reaction.

Sep 21, 2010
12:22 pm
#15 lieke wrote:

Just want to thank you for this post. I am Dutch, my boyfriend canadian, and I was 100% sure that he did the wrong thing by heating up spinach. It will be hard to admit I was the one who was wrong, haha!

Nov 10, 2010
8:56 pm
#16 Conny wrote:

You can add Austria to the countries where the myth about not reheating spinach persists! My mom claims she caused one of my sisters to get sick repeatedly as a baby because she was feeding her reheated spinach. Our family doctor, who couldn’t find anything wrong with my sister, finally told her that reheated spinach was toxic and was causing the fevers.
He forgot to mention that reheating spinach was only a problem for babies, though, so ever since, my mom’s been throwing out leftover spinach.

Nov 11, 2010
1:40 pm
#17 Andreas wrote:

Maybe it would be better to do a bit more research before posting misleading or at least controversial information on your blog. Here is an answer to the question “I heard it is unhealthy to reheat spinach. Is this true?” from the The European Food Information Council’s website http://www.eufic.org:

Spinach and other leafy vegetables contain high concentrations of nitrate. The amount depends on the variety, season, and the soil and water conditions where the vegetable was grown. Nitrate itself is totally harmless, but it can be converted to nitrites, and then to nitrosamines, some of which are known to be carcinogenic. Enzymes present in bacteria convert nitrate to nitrite. This happens especially when spinach is heated, stored and then later reheated. Nitrite itself is a harmless compound, but it should be avoided by infants of up to 6 months. It can affect the ability of the blood to transport oxygen by transforming haemoglobin, the protein that carries oxygen in the blood, into methaemoglobin, a form of the protein which is unable to carry oxygen. This can be dangerous for babies and is commonly known as “Blue Baby Syndrome”. However, in view of the fact that acidic conditions favour the formation of nitrosamines from nitrite, coupled with the facts that nearly all foods contain some protein and are exposed to acid in the stomach nitrosamine production cannot completely be prevented. Hence the recommendation to avoid reheating spinach.

Hope that helps your evaluation.

Nov 11, 2010
2:15 pm
#18 Wolfstad wrote:

@Andreas: Thank you for the link. I am not an expert, but I did do some online research when I wrote this article, and the vast majority of the websites I was finding state that reheating spinach being dangerous is an old wive’s tale / urban legend. People outside these few countries seem to agree that reheating spinach is perfectly fine.

I’ve read statements from food experts that the EU recommendation is overly cautious and misleading, and that there is no science to back their claim.

For instance this page says: “… I ran the issue by a food toxicologist to see if he had heard of this concern. We both agreed that the concerns about reheating spinach were baseless. […] I have written the European Food Information Council and alerted them to the misleading statements on their site.”

Jan 5, 2011
12:35 pm
#19 Anders wrote:

I seem to remember being told the exact same story during my childhood back in Denmark. I got worried a few minutes ago, because I was eating reheated spinach soup….

Jan 29, 2011
7:24 am
#20 Tommy wrote:

The ‘urban myth’ comes from 1980, when several packages of Iglo’s frozen food had high levels of nitrites and killed a few people. During the investigation the media speculated on the reheating of spinach in such fashion, everybody got scared of reheating spinach (and Iglo products). In the end the nitrites came from a leaking freezer. But the scare remained.

Feb 23, 2011
9:37 am
#21 Leopold wrote:

Wow, this happend exactly the opposite way to me.
I had never heard about this, although I´m german and live in Germany, until my friend, a hobby-chemist, told me that reheating spinach in the microvave causes the production of toxic nitrites.
Maybe I schould talk to him about the reliability of his knowledge…
🙂

Mar 27, 2011
1:14 pm
#22 popeye wrote:

After the whole world is dead from food poisoning, the Dutch will smile when they read this article.

Dec 20, 2011
7:57 am
#23 Caro wrote:

That Google didn’t provide you with English-spoken results depends in so many factors (didn’t you know Google results depend on your personal profile on top of the other stuff?) And thus hardly scientific lol

I’m Spanish and own mum and grandma said the same. But I also have an international background and therefore friends from many different countries and I assure you this is known/said practically everywhere else as well. And now I happen to live in the Netherlands and I had to tell my Dutch boyfriend who didn’t know!

Plus, there is some truth to it, but it’s not about cancer and also not about number of reheats but the duration of heating, and quantities.
Please do your research… 😉

Jan 4, 2012
12:08 am
#24 Olive Oyl wrote:

Tonight, my Spanish husband raised in the Netherlands refused to eat a reheated spinach dish left over from last night’s dinner – claiming that it was dangerous. I laughed, as I have been eating reheated spinach for nearly 60 years – and my mother and her siblings did so throughout their lives and all lived into their mid-90s without any cancers, etc. Until my husband’s objection tonight (perhaps he didn’t realize it, but he’s been eating reheated spinach throughout our marriage) I’d never before heard such a thing. While I wouldn’t reheat spinach repeatedly, nor at high heat – and I never prepare spinach in an aluminum pan – I’ll continue to eat and serve reheated spinach. “Waste not, want not.”

Jan 31, 2012
2:29 am
#25 Binn wrote:

Oh,so its just a myth? I’m Indonesian and I think i remembered I was being told that reheating spinach is danger. Meanwhile, i can find froZen spinach here in Canada. Oh well.

Feb 12, 2012
11:22 pm
#26 Yeptirani wrote:

Thank you so much for the information.. I’m Indonesian, and as you know, my parents, my teachers, my grands, told me to not to reheat spinach! it will be a poison! they said..

when i knew that it’s a myth, I told my parents, and you know, hard to change something we believe for years ^_^

Feb 17, 2012
2:02 pm
#27 Branka wrote:

Maybe it’ll be interesting for you to hear that some people in Serbia say the same thing. I grew up there, but have lived in the US for the past 20 years. My friend who is visiting told me about it last night, and that was probably the first time I heard about it. So looked it up today and that’s how I found this post. After a little research, I think I am safe to re-heat the spinach that I am about to consume.

Mar 22, 2012
3:01 am
#28 Christine wrote:

My French mother-in-law told me this last night as she poured the rest of my baby’s food down the sink. It had Spinach in it and under no circumstances was I to reheat it. I’d never heard of this. I am American and my mother is a dietician – all my life I’d never heard of this. I guess I’ll go bin the lovely leftover green spinach baby puree that didn’t get poured out. Thanks for the info.

Apr 29, 2012
7:32 am
#29 Kika wrote:

Long time ago I had a course with a holistic and meditation teacher to learn how to cook in a healthier way. I remember very well that she said that cooked spinach should be eaten in no more than the next 30 minutes, after this time they become toxic. Some time ago I happen to learn that results of a research about spinach conducted by Dr. Jocelem Salgado- a very well-known nutritionist in Brazil-were a bit scary. Basically, spinach can be very toxic for humans in big quantities. Also the acid present in its composition prevents the iron and calcium to be absorbed by our bodies. Apparently, many guinea pigs didn’t make till the end of the research and the post-mortem showed that there was a huge intoxication. She advice people to replace it for another types of leaves.

Sep 22, 2012
10:44 pm
#30 mick wrote:

hi, i’m dutch, and I just ate reheated spinach.. it was good knowing you, i’ll let you know if i survive

Sep 23, 2012
3:58 pm
#31 mick wrote:

I lived! 🙂 bit sick today though, guess coincidence

Oct 13, 2012
9:45 am
#32 Andrea wrote:

Something stuck in my head about being told not to put spinach in the microwave… (?) Just realised at work that I have brought my spinach-pasta leftover from yesterday and to be on the save side I googled it and nothing showed up! Where did I get this idea from then? You just answered my question: It’s my Dutch background! Living in the UK now, I am quite happy I haven’t asked anyone, that would have no doubt led to a lot of jokes about the Dutch….again… 🙂

Oct 13, 2012
9:59 am
#33 Andrea wrote:

BTW: I also remember a story about if you eat spinach with fish, you always need to have an egg with it to nutralise certain toxics that the combination of fish and spinach create. However; salmon and spinach is a classic combination. Also a Dutch legend?

Dec 11, 2012
2:25 pm
#34 katgrafix wrote:

Ok I just finished eating cooked, reheated spinach for the 5th day in a row…… how long is it supposed to take before it Kills you? By the way, it was a very tasty, spicy, hot dish cooked Nigerian style, with goat meat. I made some short grain brown rice to go with it. I reheated each dish in the microwave oven before I ate it. I’m not feeling sick yet.. how long is it supposed to take before I DIE? My husband is in Germany and he just told me about this reheated spinach legend, but it’s too late, I already ate the stuff! My advice to ALL you people in Germany, is listen to the old people, they are survivors, and they outlived Hitler and reheated spinach. If you live in Germany DONT EAT
THE SPINACH….. brought to you by Potato Eaters Anonymous of Deustchland

Dec 11, 2012
2:46 pm
#35 katgrafix wrote:

now, I’m really worried, because I decided to open a can of sardines and add to this reheated Nigerian cooked spinach and goat mix! HELP! it is really tasty, and I cannot resist. I’m having a second helping now, as I write . Is there , perhaps some antidote

Dec 11, 2012
2:49 pm
#36 katgrafix wrote:

oh, by the way. I’m living here in California, where all the fruits and nuts are grown.

Jan 14, 2013
11:42 am
#37 Popeye wrote:

And why would u reheat it (unless its a soup)?? Cold spinach leftover dishes are delicious!!
And yes, theyre only dangerous in Holland, where milk must be discarded off if it has been out of the fridge for more than half an hour and reheating most things is dangerous to health! 😉

Mar 16, 2013
7:48 pm
#38 Faith wrote:

After telling my husband how dangerous it is to reheat spinach, who by the way told me this was absolute nonsense and had never heard of it in all his New Zealand life, I thought I would have to look up the matter on the internet. Gosh didn’t realise that there were so many forums, blogs websites out there related to the subject. After reading several of them I studied the packet of deep frozen spinach bought from the Indian shop down the road to see if there were any danger signs printed on the packet, the indians obviously have no quarrel with reheating the green stuff as I could find no warning signs , the only thing that caught my attention was the fact that the spinach came from Holland. So either the Dutch don’t care about the Indians dying from nitrate poisoning or someone in the factory knew it was utter nonsense and had therefor refrained from printing any warning signs on the packet. I think I will have to let the myth go about not reheating Spinach , which is pretty hard for a Dutch girl , especially if you can hear mums’ , oma’s and the cooking school teachers voice in the back of your head reminding you of the dangers of it. As we say in Dutch the belief was pored in with the porridge spoon . Happy reheated eating from Melbourne Australia where they are oblivious of any issues that any one might have with reheating the popeye greens.

Jan 31, 2015
5:45 pm
#39 sander wrote:

Hi!
Recently got a question about this from a relative giving reheated spinach soup to her child. Found this article helpfull but maybe not robust in evidence. Here is a good article discussing the proposed dangers with food high in nitrite. I would not be worried eating reheated spinach myself but as proposed one migth be careful with infants because of the theoretical effects.
http://ajcn.nutrition.org/content/90/1/1.full

Jan 17, 2016
7:54 am
#40 Joke Debaere wrote:

I wanted to make spinach soup this morning and was about to start the process, until I heard the clear voice of my Belgian mother saying “NEVER reheat spinach!!!” It was indeed told to be a deadly thing to do.
So I postponed making the spinach soup to this evening, right before supper.
I wanted to get a second opinion from my South African boyfriend, yet he had never heard of this before.
The funny thing is, that even after reading all these comments, it still feels like possible suicide attempt to start making the spinach right now, and then reheat it a couple of hours later 🙂
thank you for all the comments, the things one finds on the net …

Trackbacks to this post. Thanks for the linkage.

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