First of all, cashews aren’t technically nuts. They’re seeds from the cashew apple, Botanically, they’re classified as drupes – not true nuts – but are commonly grouped with nuts due to culinary use.
Now, regarding the common claim that they’re “one of the worst nuts” because of PUFAs:
Cashews are actually relatively low in PUFAs compared to many other nuts. About 62% of their fat is monounsaturated (mostly oleic acid, the same heart-healthy fat found in olive oil), 18% is saturated, and only about 20% is polyunsaturated. That’s much lower than, say, walnuts, which are very high in omega-6 PUFAs. So if you’re avoiding high PUFA content for dietary reasons, cashews are far from the worst offender.
As for the urushiol concern – yes, raw cashew shells contain urushiol.
The danger here is for workers during the processing stage, not for consumers eating shelled, treated cashews.
It’s also worth noting that many plants contain natural defense chemicals – so-called anti-nutrients – but that doesn’t automatically make them harmful. Humans have been eating plant foods containing things like lectins, phytates, and oxalates for millennia. Context and preparation matter. soaking and fermenting significantly reduces most of these compounds.
It’s important to approach these discussions with nuance, not fear-based claims taken out of context…