Wikipedia reports that since 2001 pine nuts from China and Pakistan have been known to cause serious, if only temporary, taste disorders. A bitter metallic taste can occur and last from days to weeks. Incidentally, cedar nuts are a variety of pine nuts that come from Siberian. They contain an average of 59.9% fat, 16.6% protein, and 12.4% carbohydrates.
From Wikipedia: “Pine nuts are the edible seeds of pines (family Pinaceae, genus Pinus). About 20 species of pine produce seeds large enough to be worth harvesting; in other pines the seeds are also edible, but are too small to be of notable value as a human food.”
“Pine nuts have been eaten in Europe and Asia since the Paleolithic period. They are frequently added to meat, fish, salads and vegetable dishes or baked into bread.
In Italian they are called pinoli (in the US they are often called pignoli, but in Italy pignolo is actually a word far more commonly used to describe a fussy, overly fastidious or extremely meticulous person) and are an essential component of Italian pesto sauce; the upsurge in the popularity of this sauce since the 1990s has increased the visibility of the nut in America, primarily on the West Coast. Torta della nonna (literally "granny's cake") is a generic Italian dish name that in most families indicates an old family recipe for any kind of cake but often is used for a tart or a pie filled with custard, topped with pine nuts and optionally dusted with icing sugar. Pignoli cookies, an Italian American specialty confection (in Italy these would be called biscotti ai pinoli), are made of almond flour formed into a dough similar to that of a macaroon and then topped with pine nuts. ...
Throughout Europe and Middle East the pine nuts used are traditionally from Pinus pinea (stone pine). They are easily distinguished from the Asian pine nuts by their more slender shape and more homogeneous flesh. Because of the lower price, Asian pine nuts are also often used, especially in cheaper preparations. Pine nuts contain thiamine (vitamin B1) and protein.
Pine nut coffee, known as piñón (Spanish for pine nut), is a specialty found in the southwest United States, especially New Mexico, and is typically a dark roast coffee having a deep, nutty flavor; roasted and lightly salted pine nuts can often be found sold on the side of the road in cities across New Mexico to be used for this purpose, as well as a snack.”
Pine nut oil:
“Pine nuts can be pressed to extract pine nut oil, which is valued for its mild, nutty flavor. One study indicates that Korean pine nut oil may suppress appetite.”
“Pine nuts can cause taste disturbances, lasting from a few days to a few weeks after consumption. A bitter, metallic, unpleasant taste is reported. There are no known lasting effects, with the FDA reporting that there are "no apparent adverse clinical side effects". This phenomenon was first described in a scientific paper in 2001. Publications have made reference to this phenomenon as "pine nut syndrome" (PNS), or as "pine mouth".
The Nestlé Research Centre has hypothesized that nuts from Pinus armandii, which occurs mostly in China, are the cause of the problem. The nuts of this species are smaller, duller, and more rounded than typical pine nuts. A 2011 study found results consistent with this hypothesis and also suggested that chemicals used in the shelling process might be responsible.
Metallic taste disturbance, known as metallogeusia, is typically reported 1–3 days after ingestion, being worse on day two and typically lasting up to two weeks. Cases are self-limited and resolve without treatment. Möller has postulated a hypothesis—to explain both the delayed onset of, and the long-lasting nature of, the metallic or bitter taste sensation—involving a well-known physiological process known as enterohepatic recirculation (EHR), which Möller describes as a "remove-recycle-repeat" digestive process where toxins could potentially circulate through the digestive tract multiple times.”
“Pine nuts have long been a dietary staple in some Native American tribes. Today, though some tribes still use pine nuts in traditional cooking, others use the hard outer shell of the pine nut as a bead for decorative purposes in traditional regalia and jewelry. In the Great Basin area of the US, collecting pine nuts is a protected right through state law and treaty.
In the northern California regions, pine nuts are collected from the Grey Pine (or Bull Pine.) Tribes burn designs into the hard shell, reflecting the same design they use in baskets, however oftentimes they are left in blank, or burned to blacken. These are more often used in women's regalia and jewelry.”