The Perils of Pine Nuts

This morning I was warming up some beef broth for a recipe. When I tasted it for salt, I noticed that it had a bitter, almost metalic flavor. I threw it out, even though it was homemade and I had in the freezer for less than a month. For some reason it had obviously gone bad. When I ate the dish I had cooked (without the beef broth), it too had that same bitter taste, which lasted for some time after I had finished eating.

This afternoon, I made a ham and swiss sandwich out of cold cuts I had just purchased from the market. Bitter, metalic taste again. I removed the cheese and tried again. Same result.

I took to the internet to investigate the causes for a bitter, metalic taste in the mouth. All the usual suspects popped up: negative reaction to medication, gingivitis, liver disease, brain cancer... none of these seemed right. I came upon one forum, however, that seemed to deal with this very phenomenon. Dozens of people around the world had, and continue to, experience the same symptoms as me. And all the signs pointed to pine nuts. Yes, pine nuts. Those little white seeds that figure prominantly in so many recipes around the world, from italian pesto to middle-eastern kibbeh. I remembered that, while talking to a friend last night, I was munching on some pine nuts that I had purchased from Wegman's earlier in the week.

Pine nuts are harvested from the seed cones of several different conifers that grow in various parts of the world. In the souwest U.S., in countries around the Mediterranian, and in parts of Asia. The culprits in this case seem to be ones imported from Asia, most specifically China, although Russian, Korean and Vietnamese imports may also cause the same effect.

This "pine nut effect" has been noted in a number of places. Wikipedia's article on pine nuts includes a section titled RISKS OF EATING PINE NUTS. The European Journal of Emergency Medicine also describes the phenomenon, noting that "Examination of the pine nuts revealed they were oxidized and not fit for consumption."

The good news is that this nasty tast in the mouth is not a real health concern and will go away. The bad news is that it can take up to a couple of weeks to do so. To avoid suffering the same fate as me, avoid Chinese pine nuts and only use those that are grown in either the U.S. or Italy, and make sure they are from a place that has a lot of turnover in their pine nut supply.

If you are interested in reading more about this, here are some blogs and forums that may be of interest:

Pine nuts, origin and the bitter taste...

Bitter taste after eating for days - caused by pine nuts?

Bitter taste in mouth after eating

In the meantime, I am hoping that my taste buds return to normal in time for my trip to Toronto on Friday. After all, I have things to eat.