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Comment by leafmeal | Hacker News Reader

Generally you don't want to get to close to cashew trees. The seed and other plant parts contain urishiol. This is the same compound in poison oak/ivy that causes allergic reactions.

In general people who harvest cashew fruit wear lots of protective clothing.

Also, fun fact, the seeds need to be heated before being eaten. There are no truly "raw" cashews at your grocery.

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That would explain why my mother got bad allergies on her skin after handling cashews (seeds and all) from our backyard. Thanks for the info, I will look more into it.

Also watch out for mangos. I can’t handle them without having an itchy breakout because the skins contains urushiol.

Was that raw mangos? Asking because I don't remember ever having such a problem with ripe ones (nor with raw ones, actually). And have eaten plenty of both, more of raw, in fact. But guessing the raw ones are more likely to have some irritating chemical.

I would guess some people are more sensitive to it. My entire family handles mangoes (raw, ripe or whatever) and only my mother has allergic reactions. She also cannot eat mangoes otherwise she has rashes in the skin, while I eat up to 10 mangoes a day and end up okay.

Same here. Pretty much no allergic reactions to either raw or ripe mangos (in me or anyone I know), unless you call a bit of irritation or sensitivity around the edges of the lips, a reaction, that too, only with more acidic raw mangos (or maybe also with the skin of ripe mangos). I say "more acidic" because there are some less acidic, almost non-acidic varieties that we used to love and gorge on as kids - named Rajapuri or Totapuri mangos. A bit larger than the average ripe mango. Mild but really good tangy flavor. We used to eat them with pinches of salt, but they were tasty enough to eat without. I think a little sweet-sour. And you could eat a large amount without getting a stomach upset, like a couple of them.

Edit: Those were raw mangos.

We kind of figured it the hard way — it’s mango season now and she has bad allergies as always. We have been handling mangoes for years now, and she started using surgical gloves, but it still doesn’t fully prevent allergies.

Remarkably, I never have a problem with mangoes, despite being super-sensitive to poison ivy. The faintest brush of poison ivy causes a deep, weeping rash, but I handle mangoes without any protection at all.

There must be enough chemical differences to cause different effects. Whew.

Interesting, I buy this RAW cashew butter often: https://artisanaorganics.com/products/organic-cashew-butter and they claim certified RAW, so what's the catch?

They boil them

https://cleanfoodcertified.org/wp-content/uploads/2017/12/IC...

5.3.2 The exceptions to this are when Federal, State or local regulations legally require an ingredient or the entire food item to be heated at or above 212F. A regulatory exemption to the temperature treatment threshold does not impact the Bioavailability score (see 6.0 below).

Looks like you've been spending $18 per jar of cashew butter for no reason. The first result for "how to harvest cashews" says "roast the nuts at 350-400 F. (230-260 C.) for 10-20 minutes" to deactivate the urushiol. Not very raw.

Grew up climbing cashew trees and frying cashew nuts, never have I had an allergic reaction. Any literature on this you can point me to?

I just looked up this Wikipedia page (note: contains slightly disturbing photos of people's skin rashes)

https://en.wikipedia.org/wiki/Urushiol-induced_contact_derma...

and it notes that

> People vary greatly in their sensitivity to urushiol. In approximately 15% to 30% of people, urushiol does not trigger an immune system response, while at least 25% of people have a very strong immune response resulting in severe symptoms.

I've also heard this about poison ivy. (I assume cashew plants have less of this irritant than poison ivy does.)

Yeah, my mom only has to walk past some poison ivy, within a couple of feet, and she will end up with a bit of a rash.

You can also acclimate yourself to it through progressively increased exposure.

But it also varies a lot among people. My wife has no issues eating/handling mangoes but her twin sister has horrible allergic reactions.

From what I've read, along with anecdotal experience, the opposite seems to be true. Its seems like you need to be exposed to urishiol a few times before you get a reaction to it.

Often subsequent reactions are worse than the initial.

Literally the wiki page for cashews mentions the compounds in the article. Your anecdotal true life experience may be an anomaly

Seems like it might vary just as much as poison ivy exposure, and for the same reason (or nearly so, since the plants may also have other irritating chemicals that aren't the same between species). Some people are totally immune to poison ivy and don't get any reaction from physical contact with it, although not too many.

My comment in this thread might address this.

Like most allergens, people have very different reactions to it and can grow tolerance over time with exposure.

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