I have recently been alerted of a large-scale French study of which the results were released in a report just a few days ago. It was really nice to know that there is indeed ongoing work on this problem! You can download the paper here. A survey was conducted with several thousands of PNS sufferers to describe the syndrome and the results are consistent with what I see from your responses so far. Still, please do continue to fill in my survey, as I have formulated the questions to help answer some of my hypotheses of the mechanisms. I would really like to find out the WHATs WHYs and HOWs of the unusual symptoms.
It was hypothesized in the French report as well as the research of the Nestle Research Centre that a particular species of Chinese pine nuts is the cause of the problem. There isn’t a proven answer on the causative agent yet, but for now, I would advise that it is best to avoid pine nuts that look like these ones in the pictures I have attached. They are smaller than normal (0.7-1.0cm length), duller in colour, oval-ish in shape, have a strange-looking tip, but don’t taste that much different from the other pine nuts. I have observed that suppliers / distributors that have many complaints (e.g. Trader Joe’s) contain solely such pine nuts, whereas others are mostly a mixture with the medium-sized angular ones that I believe are the Korean pine nuts that have been on the market for eons.
Picture 1 (above) shows the appearance of pine nuts from some of the brands I have received. The only exception is from Delhaize of Begium, where Italian pine nuts were implicated. I am still looking into this special case.
Picture 2 (above) singles out the described Chinese pine nuts that is believed to be the source of the problem (but causative agent is yet to be determined). The sizes range from 0.7-1.0cm.
Picture 3 (left) is a close-up of the funny-looking Chinese pine nut tip and…my big fat finger tips.
Picture 4 (right) is a comparison of the size of a Chinese pine nut with that of an Italian one. The Italian / Mediterranean pine nuts are larger, of a more long-ish shape, and do not have a brown tip. They are a pretty ‘safe’ bet.
My recommendations at the moment are that it is best that you avoid these Chinese pine nuts (not necessarily boycotting China altogether) and return to the more expensive European pine nuts (weren’t pine nuts expensive all along, anyway?) I hope that my descriptions and pictures are clear enough to help you identify which pine nuts NOT to buy. You could also refer to my newly compiled list of supermarkets /suppliers that provide these particular small, oval, dull-coloured, brown-tipped pine nuts and just avoid those brands. Even though Trader Joe’s declare ‘Product of Korea and/or Russia’ on their packaging, they ARE belonging to the same pine nut species that is declared on other packaged brands as a ‘Product of China’.
For those of you who have had previous reactions to pine nuts or reacted immediately upon consuming minute amounts (2 or 3 seeds), it is probably safer to avoid pine nuts or perhaps consider testing for an allergy. Update: It seems now that 2-3 of the problem seeds CAN cause a taste disturbance. Do give me a few more weeks to look into this. Meanwhile, I would play on the safe side by avoiding the Chinese pine nuts… How about trying cashew nuts!
The Great Pine Nut Mystery 
Great research! Thank you also for your komment and the information about your project in my blog 🙂
Thank you Gerry! And for allowing me to leave the comment on your blog. There were many other sites though that disallowed / deleted my comment though! But people whom I’ve managed to reach have been really helpful 🙂
I think, they do not really like it, when you put into the comments so many links – be careful 😉
This is such a helpful page. Having pictures makes it so easy to understand the difference. One of my work colleagues has just been diagnosed with this strange condition.
Thanks for working on this. While working in London, my husband and a lot of his co workers were served mixed nuts as a snack. They all had the same problem. It took about two weeks to subside. I checked out the nuts in the Whole Foods in Kensington and the Waitrose. All were from China, but I can’t say where the caterer purchased the mixed nuts from.
i feel so sick i ate pine nuts from treaders joes 6 days ago anything i eat tastes like shit i just dont feel right…. im sick to my stomach.do u think it could be a pesticide ?????
Thank you!!!!!!!!!! I had this from nuts which I bought here in South Africa (MONTAGU brand) and which are labelled as “produce of South Africa.”
They look just like the illegitimate nuts in your excellent photos.
Effects have last a week so far… all 5 members of family affected, including my daughter of 15 who only ate 2 or three!
Pingback: Ricette Classiche: Pesto Genovese | BELLAVITÆ
I recently developed a strong bitter after taste when eating. I decided to search on the internet and found the information on the Chinese Pine nuts and they look exactly like the ones I recently purchased at the Sydney Nova Scotia Bulk Barn. I consumed about six and found they tasted good at the time. I do not know if it is related but I have also become unusually tired. I telephoned the store and informed them of the potential issue.
Thanks for the post. I have this bitter metallic’ish taste…like some strange persistent chemical. Where it came from I was more at loss to say. As I ate (semi-typical as in about 2-3 times/year) a clove a garlic on the day it began, I suspected a relationship…after all, the strong smell of garlic was easy to blame. Still, I like the taste of garlic and it seemed so strange as never before did I suffer from such a lingering bitter taste. A query online for “bitter taste” and “garlic” brought returned some retrieves which contained “pine nuts”. Alarm bells. Three days before I DID have some pine nuts for the first time in my life (at least that I was aware of). The web page https://pinenutsyndrome.wordpress.com/2010/10/20/the-ones-to-avoid/ sheds light on my seemly bizarre acting taste buds. Pine nuts look like ones shown in the pictures on that web page. My plainly marked 4.75 ounce bag of pine nuts was obtained at a cost of 4.99. I ate approximately 1/5 of the bag. The balance I still have. Pine Nut Source: International Foodsurce, LLC.; 52 Richoynton Rd, Dover, NJ 07801. It has been six days since I ate these nuts and day 3 of the bitter taste. I do notice the taste more pronounced while eating and barely notice the taste afterwards. While the bag is not marked import, the source provider’s name make me wonder if at least some of the nuts in the bag are imports. While the taste is reported as leaving harmlessly, as an environmental chemist I add a serious advisory here: what you do today will effect you, even if much later in time and place…. there is something in the nuts that we should not take and brush off so lightly just because the bitter taste “eventually goes away.” Recommend a GC-MS scan of the ingredients and review of the toxicity registries. Possible natural anti-nutrients and/or aggregated biocides at play- Galesburg, IL.
I bought pine nuts from the bulk bins at Whole food several days ago to make homemade pesto, and for the past 2 days I have had this bitter taste in my mouth every time I eat, and so has my husband. I will make sure to buy the Italian pine nuts from now on.
Hello, My husband , 2 daughters an I aparently have this pine nut syndrome. We bought pine nuts on Wednesday of last week. We all ate them, we love them so we ate lots of them. By Friday I began with the bad taste, thinking it was just me I kept quiet. But by Sunday my daughter told me she was feeling the exact same thing. Once she mentioned it, my other daughter and my husband said they had the same problem. Now that I have been googling it, I assume pine nuts were the culprit. I bought this bag at a local Lowe’s/Big 8 Grocery Store in El Paso, Texas 79924. This is what I bought ShurFine Whole Baking Pine Nuts, 5 oz bag. Distributed by Western Family Foods inc. PO BOX 4057, Portland OR 97208.
I still have the bag with some pine nuts in it.
Like other people I was curious as the cause of a persistent metal taste in my mouth. I googled and found that the pinenuts and pesto I used for a pasta dish on Tuesday could be the cause. I purchased both in Tescos and apart from the pine nuts being smaller than usual I didn’t notice any difference in the taste. However, the after affects are driving me mad.
Krinos brand pignolia nuts did it to me. This is awful!
I baught Trader Joe’s pine nuts on Saturday by Sunday I had a bitter taste in my mouth their pine nuts are from russia and korea but I had the same effect as the chinese ones. It was a fresh bag just opened. can’t wait for this taste to go away.This is tuesday and I still have the bitter taste.
Anyone else have problems with trader Joe’s pine nuts.
Deb
I’ve gotten it twice: once from Trader Joe’s pine nuts, and another time eating my favorite salad at the MOMA cafe in NYC. They had substituted the expensive Italian pine nuts they had been using with tiny little Chinese ones. I scraped off as many as I could but they got me anyway.
Thank God for people like you Grace. I purchased my pine nuts from Trader Joes and will be visiting them today to bring the problem to their attention in hopes that they remove them from their shelves.
I’m on Day 3 of Pine Mouth. The offending nuts in my case came from Trader Joe’s, and were bought last week. I snacked on them for a few days before noticing Pine Mouth. During that time I also made a batch of pesto for a special birthday meal for my son yesterday. By yesterday morning I realized I was in the throes of Pine Mouth, and didn’t want my family to suffer, but also didn’t want to disappoint them with another menu. Luckily I had some older pine nuts in the freezer which had already been opened and had caused no problems, so I whipped up another batch. Everyone but me enjoyed it!
Yesterday morning I noticed this bitter taste in the back of my mouth while eating a couple of fried eggs. I told my wife I thought I had eaten a rotten egg and hoped I didn’t get sick. I then noticed that everything I ate from then on had the same reaction in the back of my mouth and was getting ready to call the doctor. This morning my wife started having this reaction to everything she was eating so we traced what we had eaten back a few days and then I googled “Bitter Taste in the Back of Your Mouth” and “Pine Nuts” appeared. We both ate them about three to four days ago. I am wondering how long does this syndrom last?
Thanks,
Gary
I ate 100g of pine nuts on 9th April and started to experience PNS on Monday 11th after eating a hard boiled egg. The nuts were purchased from Holland & Barrett. They are Neal’s Yard, Pine Kernels, Produce of China, best before March 10 (so out of date but they were not rancid). Marked as Healthy Choice, nutritionally balanced. Distributed by NBTY Europe Ltd., Burton-Upon-Trent, DE14 2WP. I have the packet with one nut left inside if anybody is interested. Also, I had two dark green motions the day after I ate the nuts. I am intrigued by what is causing this. I still have the bad taste in my mouth.
Dianne
Three days ago I ate pine nuts in a salad at a chain restaurant – Le Pain Quotidien. Last night, I noticed that yogurt tasted bitter, but other food seemed fine. Today, everything tastes bitter – even water.
I experienced pine nut syndrome last week three days after eating a few small Chinese pine nuts on a salad. The bitter aftertaste lasted about five days and was most noticeable after eating something blandly sweet–bananas, sweet corn, pretzels. They were Piggly Wiggly brand packed by Eillien’s Candies Inc. of Green Bay, WI with a sell by date of 10/16/10 (oops!). They’ve been in my refrigerator since last fall and I’ve eaten them on salads every so often with no ill effects before. My husband who ate them at the same time did not have the problem.
On June 8 or 9 I ate some raw pine nuts for the first time in years. A day or two later, everything i ate tasted bitter. Googled ‘everything tastes bitter’ and found the pine nut link. Mine were purchased from Trader Joe’s. I called the store and the lady hadn’t heard any complaints. She asked if I’d bring my nuts in so they could have them tested. Hope the bitterness goes away soon. There’s enough bitterness in the world. Thanks for collecting all of this information, Grace. Let me know if you want more info and congratulations on completing your thesis!
Just noticed on my bag of Trader Joe’s pine nuts it reads:
‘Some individuals may experience a reaction to eating pine nuts, characterized by a lingering bitter or metallic taste.’
Unfortunately I can’t find the article back, but some time ago I read they found the case for ‘pine mouth’.
Apparently there’s an inedible Asian type of pine nut that causes this, and unfortunately they regularly get mixed in with the edible Asian pine nuts, because they’re so cheap (being inedible and all that).
This is the article marcelle is talking about: http://www.which.co.uk/news/2011/03/pine-mouth-lingers-on-249471/
Wow!!! amongst many other things I could say….I have spent the past couple of months wondering what was wrong with me and it coincides with my current pesto addiction. However, I would not have had a clue about this had I not done a bit of scouring on the internet. I have never had the problem with jarred pesto so maybe that is a different pine nut….but the ones I have been making pesto with are from China. It’s such a relief that I think I have an explanation. now where can I get Italian pine nuts from?
I’m from SIngapore and have been eating pine nuts for years. Suddenly I started having the same problems last year. One batch after another gave me the same problem even though I bought from different stalls. But I am sure they all came from China. After that incident, I stopped buying altogether.
Early this year, I bought some from Hong Kong, also the short stubby type and experienced the same horrible effect. I threw that away.
Last week, I was in USA and bought a pack from Trader Joes and began eating them today. So far I have not experienced any metallic taste in my mouth. I happened to come across your blog today and read your warning about the ones from Trader Joes. Now I am keeping my fingers crossed and if nothing happens within a day, they should be fine for consumption.
I developed the same bitter metallic flavor in my mouth as well. This was after eating pine nuts from Trader Joe’s. The packaging indicated that these nuts were from China, Korea, and Russia. This article is such a great resource. Thank you for doing the research. I would also suggest reading another excellent article by Dr. Greggory Moller entitled “The Curious Case of the Epicurean Nut”, Food Technology Magazine, May 2010 Issue. http://www.ift.org/food-technology/past-issues/2010/may.aspx
I am in the throws of PNS from a bag of Dry Toasted Pignolias from Trader Joe’s (Best by June 15, 2013). It does contain the disclaimer about a “lingering bitter or metallic taste.” I had never heard of Pine Mouth before. I’ll be taking this bag back and avoiding all pine nuts henceforth! Almonds are just fine in pesto.
Care its latterly announced smaller sib, the P runs Humanoid 2.
3.7 atop a 1 GH z telephone with one script merely. An impressive
tv camera on the Sony Xperia P Цена enables you to
captivate total High Definition television low-priced cost,
and so Sony Xperia P Цена is a unquestionably a bright alternative.
Substance you will be iconic Xperia seem with the unequalled Xperia
logo along the underside, this new sony xperia p цена is effortlessly
beautiful.
Hi, I do think this is a great website. I stumbledupon it 😉 I will revisit once again since
i have book-marked it. Money and freedom is the greatest way
to change, may you be rich and continue to help other people.
I found mediterranean pine nuts at nuts.com — they’re much more expensive, but worth it.
I have a feeling that toasting the pine nuts is at least part of the problem. I’ve eaten pine nuts before without any ill effect. Last week I bought a bag of pine nuts from my local Co-op (in Oxford, UK) and there was something slightly rancid about the smell of them, so I decided to toast them and ate the lot. That’s the price of greed. Two days later and everything tasted like bitter ashes. It’s being going on for almost a week and of course I assumed it was a brain tumour. Thank God for google. Reading the posts above, though, I do wonder if the toasting of the nut has something to do with it…
PS. Also experienced diarrhoea, upset stomach and a red rash as part of the reaction.
I doubt if toasting is the problem. My experience with the bitter taste was with untoasted pine nuts from China. I ate only a few on a salad and the pine nuts themselves smelled and tasted fine. It was just everything else that had a bitter aftertaste for about a week after I ate them. I have eaten and toasted pine nuts from Italy with no problems.
Great article. I have experienced pine mouth on two occasions . I have learned to avoid Chinese pine nuts, which seems to be getting harder to do because these have almost replaced all others in the stores. I am still looking for pine nuts from the USA but they seem to have disappeared from the stores. Even most health food stores are stocking nuts from China.
Very helpful article – many thanks. My daughter and I have both gotten the pine mouth syndrome on a few occasions. It is very frustrating trying to find nuts that are safe and not from China. I found some Italian ones on Amazon, but they are $86.for a pound.
I wanted to say that we find eating foods with vinegar such as pickles or salt and vinegar potato chips works quite well to stop the bitter taste. I hope this helps some of you folks..
Interesting article, I tend to purchase himalayan pine nuts usually imported from Pakistan. Can safely say haven’t had any such issue and found them to be the largest and tastiest kernels. There are also several articles published by newspapers stating that chinese pine nuts have an issue with them. The UK FSA (food standards agency) site also acknowledges that China is now putting restrictions in place for pine nut exports to the EU.
I purchased some packaged bulk pine nuts from Natural Grocers and immediately developed pine mouth. I contacted them about their source and they researched it with their supplier and they emailed back and said they were from China. They said that they were going to investigate it further, but I’ve never heard back. I suffered with pine mouth for two weeks before I read a suggestion to swish with coconut oil for as long as possible (10-15) minutes. This is also called oil pulling. It worked wonders and the first time. I’d recommend the same method for anyone currently suffering.
Chinese Pine Nuts gave me PNS a few years ago. Avoiding those, I’ve had no problems with pine nuts since. I am very careful about them now.
Pingback: Friday Weird Science: The curse of the tasty pine nut | Neurotic Physiology
The red and white pine nut from china is the one to avoid. It was formerly considered edible and has been traced as causing the metallic taste, all others including the Korean and Japanese varieties are fine.
Yes, I get a days-lingering bitter taste from the stubby pine nuts. Fortunately, some Googling revealed the mystery, and I have been enjoying Italian pine nuts just fine!