Update: 12/11/10

Getting very much busier as the days of chemical analysis have commenced. Searching for the causative compound is like searching for a needle in a haystack… gosh I had no idea how much time / work is involved to do a screening of just one sample!

On another note… I had mentioned in my previous post that a particular species of pine nuts was observed across all the problem samples. However, because this species has been consumed in China for years, I had the impression that not all of these small oval-ish pine seeds will cause bitterness. And so I had a kind friend help me to purchase a pure batch of these from China (pic: right)… when I saw that the tips were slightly less dark than the ones in some of the problem samples, I was even more convinced that they would be fine. So I happily popped a heaping teaspoon of it from the freshly-opened packet right into my mouth (they tasted great, by the way!) and voila, I’m on board again with pine mouth [beginning Day 3 now]. Once again, I’d like to reiterate that if you see these particular seeds (pic: left and right) in your supermarket pine nuts, please avoid them until the mystery is solved. Doesn’t hurt to play on the safe side. Sometimes they are present in such small amounts that you don’t notice them until you take a very very close look. I will make a picture post soon of the different types of pine nuts I have seen in the supermarket samples.

That’s it from me for now… I would like to ask again for your help and patience — I am still collecting samples and complete survey responses for the research. In these next few weeks, I am planning a taste sensitivity test which I would like to involve some of you (if you have filled in the survey, you’d probably will be receiving emails from me in the coming weeks!). I will also be contacting some of you individually to resolve some blanks.

Thank you all for your help and here’s a quick statistics update again:

  • Number of hits: 3250
  • Number of surveys done: 171 (and 20+ more incomplete)
  • Number of samples received: 26
  • Number of samples promised but yet to be received: 26 (I’m still wondering about some who said they will send the seeds 5-6 weeks ago. If you’ve decided not to do so anymore, do kindly drop me an email, thank you!)
  • Number of samples I hope to receive: 50
  • Number of surveys I hope to receive: 200-300
Posted in Announcements, Research Updates | Leave a comment

Update: 30/10/10

It is now Week 7 of research. I’m starting to get used to being greeted ‘Hey grace, you’ve got mail’ / ‘Hey grace, how’s pine nuts?’ instead of the usual ‘how are you?’. Oh well! Somebody asked if I am sick of pine nuts yet?…gosh no, not yet! This is only the beginning.

It has been a particularly amazing week for me and pine nut research. Apart from the kind responses and generous contributions of samples that have been streaming in, a few very knowledgeable parties have come forth to share their expertise and resources in pine nuts and their findings on this issue. Special thanks to Penny — for she who has dedicated her life to protecting and promoting pine nuts is now actively assisting our quest to unravel the pine nut mystery by chipping in with her wealth of grower’s knowledge!

Here is the working space I have just been allocated to this week. I’ve spent much of the past few weeks at home and in the library, perusing journals, books and answering emails. Now I work in a cold (15˚C brrr…) food-grade room, and I’m in the midst of sorting and documenting the pine nuts within the samples that I have received so far. At the moment, a clear observation is that these samples are mostly a mixture of 2-3 species from a selection of 4 species I could visually identify. The one that I have featured in my previous post of ‘The Ones to Avoid’ is common across all the samples — be it in 50% mixture or as few as 2-3 seeds amongst a hundred. And indeed, 2-3 of these seeds have been enough to cause myself and 3 other people symptoms. I am still working hard to sort the samples for analysis (lumping good and bad seeds together is just going to dilute the results of the analysis and complicate matters), and so here I am sorting seed by seed by seed in preparation for the tests. Not yet an expert in identifying Pinus species (ordered some seeds from tree growers and pine nut suppliers for reference) but soon enough, I will be. Just a sneak preview of one of the samples:

Berkley & Jensen Pine Nuts, sorted. The ones at the bottom were common across the samples I have received so far. Some problem samples consisted only 1-2% by weight of these seeds.

I will make a post of my visual findings when I am done sorting and identifying this batch of samples (I still need more, please contact me if you have some to send, THANK YOU!!). For now, here’s a quick update on the statistics:

  • Number of hits: 1737
  • Number of surveys done: 133
  • Number of samples received: 23
  • Number of samples promised but yet to be received: 18
  • Number of samples I hope to receive: 50
  • Number of surveys I hope to receive: 200-300

Do help me to spread word of my research, as the more people we have on this, the more information we can gather, and the better are our chances to find a solution to the problem! Speakers of other languages, I need your help too! I’ve gotten/found reports of cases from Finland, Sweden, Norway, Denmark, USA, Australia, South Africa, Germany, France, Poland, Iceland, China, Canada, Netherlands, Belgium, UK — that’s just too many languages for one Singaporean to handle. Losing enough sleep over pine nuts as it is. :S Thank you all, and I will keep you updated to the best of my abilities.

PS: Thanks Luke and Penny for taking the time to write up a post about my research!

Posted in Announcements, Research Updates | 1 Comment

The Ones to Avoid

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!

Posted in Research Updates, The Great Pine Nut Mystery | 41 Comments

I think I might have pine mouth…

One of the few hypotheses that I am trying to figure out now (thanks to the advice of several pine mouth sufferers) is that bitter sensitivity could play a role in whether one experiences severe / mild / no symptoms of pine mouth after ingesting the incriminating pine nuts.

As a Chinese Singaporean, I love eating bitter foods such as bittergourd (a.k.a. bitter melon) with spicy soyabean paste [Picture source: The Cookbook Chronicles] and I would drink some bitter Chinese herbal drinks and strong black tea without any sweetening. Somehow it made me believe that I might not be at all susceptible to pine mouth.

Wednesday afternoon. I gave in to curiosity and decided to taste the pine nut samples that I have received. Pine nuts have never really been part of my diet (I’ve eaten it a couple of times in my lifetime) and I’m not very familiar with the taste to be honest. And so I tasted some small seeds, some oval, some more angular, some darker in colour, and also the one sample of big Italian ones that I have received. I also tried tasting the weird-looking tip of the seed separately. Oh, I bought capsules of PinnoThin (containing Korean pine oil) to taste too! I was curious to know how they differ in flavours, whether the samples were really rancid, or were they characteristic flavours of the seeds, or if the toasted ones from Trader Joe’s taste different from the raw ones? I was very cautious though, eating no more than 10 seeds.

Friday afternoon. Just before I headed off for my regular squash games, I started to feel a little bloated and uncomfortable in the tummy area. It must be the junk I’ve eaten (I am quite a compulsive snacker). Later that evening, I had a spicy-food sharing session with my Mexican and Malaysian friends and my mouth was burning of spice almost the entire night. Didn’t really notice anything except for a headache from the lack of sleep. I had an early night, but the next day (today), it seemed that my ice cream, peanuts and pretzels especially when the salt crystals dissolve! left a bitter-ish / sour-metallic taste in the mouth that lingers at the back and posterior sides of the tongue for a while but goes away soon after I rinse my mouth with tea. I wonder, if thinking so much about the pine nuts is making me imagine things (just like how we can salivate by just thinking of lemon juice), or am I really experiencing pine mouth??

Will see how it goes tomorrow. At least I now know how these pine nuts taste like, and that the ones I have received weren’t particularly off-tasting compared to fresh ones from a packet.

A couple of other posts coming up! It’s been a busy week, so I had to leave many things to the weekend~

PS: I have just realized recently after creating this blog that I have named it the same as The Greasy Spoon’s post on the syndrome. I must have come across it in my earlier searches and the catchy name stuck somewhere at the back of my mind. Thanks to the author who didn’t mind me keeping it 🙂 This blog, being relatively new, still has yet to appear on searches, so everyone please do help spread the word of this research! Thank you!

Posted in Miscellaneous, The Great Pine Nut Mystery | 2 Comments

Update: 16/10/10

Hi everyone!

Thank you very much for your detailed survey responses and for the additional information and research suggestions / resources you have provided! (And the lovely encouragements too!) Looking through your responses has been giving me many insights into the problem, and I assure you that I will continue working hard to understand the causes and mechanisms behind it. Do keep the responses coming in (please also ask your friends who have suffered from pine mouth to help fill in the survey), I am still far from target. Here are the current stats:

  • Number of hits: 800
  • Number of surveys done: 96
  • Number of samples received: 13
  • Number of samples promised but yet to be received: 20
  • Number of samples I hope to receive: 50
  • Number of surveys I hope to receive: 200-300

This week has been especially eventful and information-loaded, and I am trying to handle all the responses as best as I can. In other words, if you have posted a comment on the blog or written a note in your survey response that deserves a reply to, do give me a few days ok? – I have absolutely no intentions of ignoring anyone. We’re working with an almost-blank sheet now, and every bit of information you can give is a valuable piece to the puzzle. A few bits of news to share, I will post again really soon, some time this weekend.

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Update: 10/10/10

Hi everyone,

I was amused with the nice numbers of the date today, so I thought I might well do a quick number update to let you know how things are coming along. It has been 2.5 days since the launch of this blog, and so far the stats stand at:

  • Number of hits: 344
  • Number of comments: 1
  • Number of surveys done: 19
  • Number of samples received: 11
  • Number of samples promised but yet to be received: 18
  • Number of samples I hope to receive: 50
  • Number of surveys I hope to receive: 200-300

Thank you for your contributions so far! I really wish I could send each and everyone of you a personal email to thank you for your time and interest in this research, but it does take a lot of time writing individual emails. With the growing number of responses, it leaves me with little time to handle the other aspects of the research (research proposals, laboratory tests, reading journals and books, speaking with the professors). My sincerest apologies that I have to handle this in an increasingly impersonal manner!

I will post a little update about general survey findings when the numbers are a little higher (I don’t want to raise any premature alarms!). However, with these current responses, I am already beginning to notice some patterns–though, it is definitely not sufficient for proper research.

As this is a new blog, it has yet to start appearing on internet searches. Hence, if it is not too much to ask, may I request that anyone who has a blog / platform that reaches out to pine mouth sufferers, to please direct them here and to relay my pleas for survey responses and samples? If you would send me an email at pinenutsyndrome@gmail.com, I will be more than glad to link your site to this blog. Thank you very much! 🙂

Posted in Announcements | 1 Comment

Hello and Welcome!

Dear readers and sufferers of the pine nut syndrome,

this blog is dedicated to YOU.

Today marks an exact 4 weeks since my first meeting with my supervisors Assistant Professor Markus Stieger and Professor Kees de Graaf at Wageningen University to launch the project of unraveling the pine mouth mystery (click here to see who we are). Since then, I have been collecting information from literature, from forums and from your fellow pine mouth sufferers, and have made my best attempt to share what I have so far in this blog. I hope that the information I have (and will have, in the next few months) put up here will help you deal with your pine episode, or to perhaps give you a little consolation that at least 3 people in this world are trying really hard to get to the bottom of the matter.

At the same time, I must stress that the nature of research is that success is not guaranteed nor defined within fixed time frames. I can only promise you that I will try my utmost best, and with your help of offering relevant information and problem-causing samples, I believe that we will at least gain some insight into this issue. You with me on this?

My professors and I would like to extend our deepest gratitude to the 30+ individuals from USA, UK, Finland, South Africa, Netherlands, Belgium and Canada, who have enthusiastically responded to my earlier posts on blogs and forums (without even questioning my identity and intentions) with offers of samples, information and ideas, and magnanimous rejections of any offers of repayment. The information they have provided in the past few weeks have formed the basis of our hypotheses, the skeleton of this blog, as well as the materials for the upcoming experimental work.

Kijk! (that means ‘look’, in dutch) I have received your mail! 🙂

We are, by the way, still looking for more ‘problem’ samples and detailed reports of pine mouth experiences, so do fill in the SURVEY and drop an email to pinenutsyndrome@gmail.com if you have samples to send!

Meanwhile, feel free to browse, to leave your comments, to share your experiences, to encourage each other, and perhaps, to offer me some scientific expertise? Do forgive me if this site is lacking in any way as I have put it together very quickly whilst handling a heavy initial workload and the vexing inconveniences of resettling down in a foreign land. I will continue to improve on this site (with the help of your comments!) and to feed you with any updates I have as we go along! Do subscribe in the right side bar to receive notifications of updates via email!

A million thanks and blessings, from Grace.

Posted in Announcements, General Information | 2 Comments

The Great Pine Nut Mystery

Pine nuts have caused an unusual sensory disturbance that has driven countless people absolutely NUTS. You open a packet of pine nuts, pop some into your mouth and mix the rest into a dish. Two days later, your world is turned upside-down, as a repulsive bitter-metallic taste dominates all that you attempt to ingest for the next 1-2 weeks or more. The coffee tastes awful, and so does the toast… and the tomatoes, and the jam. OMG just what’s going on???

You might perhaps be wondering why…

1. you have been enjoying pine nuts for all your life without any problems and now, this;
2. it has been previously reported but no effort has been made to warn you;
3. your doctors hadn’t an inkling of it and suggested all sorts of frightening tests and scans that yielded no answers but a perpetuated fear of liver disease and brain disorder;
4. your supermarket received complaints from many customers but did nothing about it;
5. … they aren’t nuts, they’re seeds, yet they’re called nuts.

The pine nut syndrome (also known as ‘pine mouth’) was first described by a Belgian anesthesiologist in 2001, when a colleague’s second episode of taste disturbance and concurrent complaints by family and friends who shared a dish prepared from the same package of pine nuts raised the alarm. Several local case reports and taste experiments later, this phenomenon was diagnosed and published in the European Journal of Emergency Medicine [1] with many question marks and zero answers. Yet ironically, despite this ’emergency’ label, the pine nut syndrome remained appallingly unknown and unexplained, under-described and under-researched.

The years of 2001 – 2008 remained a mysterious vacuum on this topic until the recent boom of blogging mania. A handful of perceptive food bloggers [David Lebowitz, Roger Hyam, PinchMySalt, Babyccino, etc etc] linked their symptoms to pine nuts and wrote about their experiences, attracting hundreds and thousands of ‘me too! I ate pine nuts too!’ responses from all over America and Europe. Yet oodles of complaints to supermarkets and food authorities later, these products stubbornly remain on the market, with complaints snubbed with excuses like ‘no serious health complications’ or ‘just a few isolated cases does not warrant a boycott’. This prompted Munk, an assistant professor in Emergency Medicine (ah, ‘Emergency’ again), to make yet another case report in the Journal of Medical Toxicology this January, 2010 [2], calling it an ‘EMERGING problem’, a good 9 years after the first reports. Gee.

Good news is that the food and news agencies [USA, UK, Netherlands, Denmark…] are finally starting to shed some light on this phantom phenomenon, that growing awareness is helping people to identify their symptoms. Not so good news is that there aren’t any real answers yet – just hypothetical ideas based on a couple of diagnostic studies.

Do you want to know more? I want to know more. We all want to know more, don’t we? Read on for more about…what is so scientifically unusual about the pine nut syndrome, a review of the current research status,  the pine nut species we’ve been eating, or to find out about me and the research team, and how you could make a valuable contribution to the research by sharing your experience, telling us where you got your pine nuts from and taking time to complete the survey.

(1) Mostin, M. (2001). Taste disturbances after pine nut ingestion. Presented at the XXXVIII Congress of the Society for Clinical Toxicology (abstract). Journal of Emergency Medicine, 8(1), 76.
(2) Munk, M-D. (2010). “Pine Mouth” Syndrome: Cacogeusia following ingestion of pine nuts (genus: Pinus). An emerging problem? Journal of Medical Toxicology, 6, 158-159.
Posted in General Information, The Great Pine Nut Mystery | Leave a comment