The raw cashews are then roasted at high heat, either by steaming them in a large rotating drum or vat of boiling oil to remove urushiol remnants before they can be shelled, thoroughly dried, and peeled. At this point, these cashews are still often labeled as raw, since theyre free of added flavorings. Cashews may be roasted a second time for flavoring purposes if theyre being sold as roasted cashews. Another round of roasting may also help ensure any remaining urushiol residue is removed before sale. Commercial cashews are then ready for quality checks, packaging, and sale. SUMMARY Truly raw cashews are still in their shell, which cannot be eaten. Even cashews sold as raw have been roasted once after being carefully harvested and shelled to remove any toxic oil residue. What toxins do they contain? Cashews naturally contain a toxin called urushiol. Urushiol is a substance found in all members of the Anacardiaceae family of trees, which includes cashews, mango, poison ivy, poison oak, sumac, Peruvian peppers, and pistachios (3). While urushiol resides in all parts of the plant, including the roots, stem, and leaves, it also tends to sit in the oil between the cashew shell and nut inside. Coming into contact with urushiol commonly results in allergic contact dermatitis, a delayed skin rash in humans thats similar to one you might experience after exposure to poison ivy (4). An urushiol-induced skin rash appears as bumps or patches on the skin that are itchy, inflamed, and may have secretions, potentially even causing an intense burning sensation or localized swelling (3). A 1982 report from the Centers for Disease Control and Prevention outlined how 7, 500 bags of cashews containing urushiol residue were sold along the East Coast as part of a fundraiser, causing around 20% of the purchasers to experience a rash (5, 6). In an older animal study, cashew nutshell extract was fed to rats in varying amounts, resulting in a wide range of symptoms, including licking, scratching, tremors, increased pain sensitivity, mucus secretions, passive behavior, and even death (7). The type and degree of reaction may depend on how much urushiol youre exposed to and whether you consumed it or had direct skin contact with it.
