At a young age I discovered that I am allergic to Pistachios. As a young adult training to be a Peace Corps Volunteer, I discovered that I am very allergic to Mangoes. What is the connection?
They are both plants in the Plant Family: Anacardiaceae. Interestingly enough so is the Cashew, yet I very rarely exhibit any reaction when eating cashews. For medical and scientific reasons that are far beyond my comprehension, all possess the toxin known as urushiol. For those of you that clicked on the link, you will also note that urushiol is also present in Poison Ivy, Poison Oak and Poison Sumac. All three of these plants are also a part of the Plant Family: Anacardiaceae.
When I think back on how I learned that I was sensitive to pistachios and mangoes, but rarely and only mildly with cashews a small amount of deduction reasoning helped create the complete picture. The oil urushiol is found in the skin of the mango and the shells of the pistachio and cashew. Given that it is near impossible that to slice a mango without exposing the fruit to the oils released from the skin, the urushoil makes contact with the fruit. Likewise, since most pistachios come in their shells, one cannot avoid touching the shell to remove the nut. The process used to remove the cashew from it’s shell is to roast the shell. Proper roasting of the shells destroys the toxin. One could surmise that pistachios are roasted differently and the presence of the shell with the nut makes for contact with the toxic oil more likely.
It was my father, with his passion for horticulture that uncovered this relationship (before the age of internet search engines) after the incident of with the mango. The irony of this discovery and having been given nickname “Musa Dutoe” (Moses the Mango in Mandinka) from my fellow Peace Corps Volunteers is that Mangoes and Cashews grew with little effort in the Gambia in West Africa where I was stationed as a Peace Corps Volunteer in 1993-1995. While my friends gorged on mangoes, enjoyed locally shelled cashews and the soft fruit of the cashew known as a cashew apple, I stayed far away from these foods.
Whereas my father was extremely allergic to Poison Ivy, I only exhibit the standard reaction to the plant. It is the eating some of the fruit and nuts of the family Anacardiaceae that causes me so many problems. What a shame.