Cashews, pistachios and mangos, oh my

Published 9:09 am Friday, January 31, 2020

Somebody told me about getting poison ivy itch from eating cashews. I looked it up and found out not only cashews, but pistachio and mango are in the family of plants that contain urushiol. Now that’s a word I have been familiar with for a long time.

My amateur phonetic spelling attempt for pronouncing it is yer-ooh-she-awl.

Urushiol is the oily chemical substance produced in some plants that causes people to have skin allergic reactions. The good news is store-bought cashews, pistachios and mangos aren’t going to bother the overwhelming majority of us.

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In poison ivy, urushiol is present in all parts of the plant, from leaves right on down to roots. For folks very sensitive, all it takes is brushing up against leaves to cause a reaction. For those of us who don’t get a rash by brief leaf contact, oil released by cutting or pulling up plants might nail us.

But in cashew plants, as well as those that yield pistachios and mangos, urushiol is confined to very limited areas, making it possible to eat the produce. It is the cashew nut shells that harbor the itchy oil. That’s why the people who have to be most aware and take precautions are the ones who harvest and process cashew nuts.

True, a bit of the oil might get on nuts, but the shelled cashews we buy have been rendered safe by roasting. Even so-called “fresh” cashews have been cleansed of urushiol by boiling beforehand.

It is also the shells of pistachios on trees that contain the allergen. But that’s the outer shells we never see.

Pistachio shells with the nuts marketed to consumers are the inner shells: no urushiol or not enough to matter.

And mangos? There is some oil in the rind, significantly more where the mango fruit was attached to the stem before harvest.

Again, the people doing the harvesting and handling of the fruit where grown are the ones who need and get protection from urushiol.

I don’t know how many washings mangos get before display at the store, but peeling sends whatever oil might be left to the landfill or compost pile. But never put poison ivy in compost. The full-strength stuff lasts too long.

Although rare, there are those among us who are sensitive enough to any minute level of urushiol that they have had rashes breakout after eating cashews or had itching of lips after eating mango.

For those unfortunate few, I say tell your doctor about it and life can still be good without cashews or mangos.

The older I get the more good things to eat and drink I have to abandon because they cause nasal swelling, funkiness of the throat and other allergy symptoms. So far I refuse to quit coffee but it might happen.

Now, for some itch-free plants, remember Arbor Day tree seedlings will be handed out Friday morning by the Warren County Soil and Water Conservation District at the USDA office on Sherman Avenue.


Terry Rector writes for the Warren County Soil and Water Conservation District.