Zel's Vegan NutGourmet

Zel Allen Goes Nuts for Good Health

SCIENCE EXPLAINS THE CASHEW AND MANGO DILEMMA

Posted by Zel Allen's nutgourmet on January 22, 2012

Within a few hours after I posted my family’s experience with allergic rashes from consuming mangoes and cashews, I received the comment below. It’s so well explained in scientific terms I thought it important to share in a post rather than a comment.

The information comes from Sandra J. Baker, author of The Poison Oak & Poison Ivy Survival Guide.

Thank you so much Sandra. Your information explains the science behind my husband’s and two sons’ itchy rashes after eating mangoes and cashews. Hopefully, this post and the previous one will benefit others who suffer the misery of itchy skin rashes and haven’t discovered the cause.

Sandra writes:
I can add to your quest for information. Mango, cashew and poison oak, ivy and sumac are all in the family Anacardiaceae. Then poison oak, ivy and sumac join the genus Toxicodendron which contains the allergenic oil urushiol in its resin. But, mango and cashew also have allergenic oils. Mango has resorcinol, and cashew has anacardiol and cardol. All of these allergenic oils have enough similarity that if you are allergic to one, you are probably allergic to the others.

Mangos’ allergenic oil is mostly in the resin canals in the skin (always peel first before eating), and is thought to be somewhat weaker than poison oak/ivys’ oil. Some people are extremely allergic to it, but a mango grower said his workers usually don’t get much of a rash at the beginning of working with the plants. After a while, the sensitivity usually goes away. The oil can migrate from the skin into the flesh, so it is a good idea to stay away from all mango products, even juice if you know you are allergic.

All cashews imported into the US (even those labeled raw) are shelled and cooked a bit beforehand, because that will destroy the allergenic potential of the cashew nut shell oil that is between the honeycombed layers of the shell. (the oil of the cashew itself is harmless). (Poison oak/ivy and sumac oil is highly resistant to heat by the way.

Very seldom, cashews are accidentally imported without being cooked, and may have been contaminated from the shell cracking procedure, Rashes have been documented. This is a much smaller problem than that of mango rashes.

39 Responses to “SCIENCE EXPLAINS THE CASHEW AND MANGO DILEMMA”

  1. Muriel Jelsma said

    Am a new vegan and just found this wonderful site.
    In the 70s I lived in Costa Rica and discovered I got a rash From raw green mangos. However, I amiable to eat them if cooked in chutney. However, raw ripe mangos don’t bother me so far.
    Growing up in the states, poison oak and poison ivy really attacked me—now I know why.

    • Zel Allen's nutgourmet said

      Hi Muriel, I’m so happy to know my blog post was helpful to you. Sometimes allergies pop up and surprise us. Even more surprising are the food families, such as mangoes, cashews, pistachios, poison oak, and poison ivy. Most people would never connect them. Since it’s been several months since my husband’s giant allergy rash disappeared, he’s feeling ready to give fresh mango a try, but in very limited quantity. Thanks so much for sharing. Zel

  2. Jayne said

    Thanks for all the interesting info. I myself broke out in a horrible rash. I went to the dr and have been tested for liver diseases, celiac ect. I just remembered tonite that I ate alot of honey roasted cashews. I am waiting for the results but I will call the dr to tell them my self diagnosis!

    • Zel Allen's nutgourmet said

      Hi Jayne,

      I’m always delighted when people are able to find that a-ha moment that brings awareness their weird rashes are the body’s way of telling them it wants to reject something you’ve eaten. Food allergies pose many challenges. The cashew/mango/poison ivy connection is one people rarely connect with, but if you read some of the other comments people have posted, you’ll find you’re not alone with this challenge. Both my husband and our son are now avoiding that food family and the ugly, itchy, and sometimes numbing rashes have disappeared. Your doctor may appreciate you calling this to his attention. Doctors don’t often connect health problems to foods that actually may be the culprit. So glad you’ve made that connection. Good health to you!

      Zel

  3. Missy W said

    My friend told me about the connection between mangos and cashews because her son was just tested. I m wondering why I would have had an allergic reaction to a mango however I have absolutely no problems eating cashews. I am confused by this fact. Could there be something else in the mango that I am allergic to that isn’t in cashews?

    • Hi Missy,

      It could be the oils in the mango skin causing you an allergic reaction. That same composition of oils may not exist in cashews. However, I would suggest you not overdo the cashews–large quantities may just push your body’s tolerance over the edge and create an allergic reaction. My husband had been eating large quantities of cashews daily for years without a problem. About a year and a half ago we went to the Philippines and ate generous portions of mangoes daily. That triggered a dramatic reaction for my husband–an itchy rash on his legs and his back. Back at home, my husband dug into the cashews again, and shortly after, he began itching. Next day, his legs and back were broken out in a giant rash. And all it took was one handful of cashews. Just be cautious to learn your body’s level of tolerance, and then, don’t push it.

  4. Norma said

    The upset stomach I had eating cashews finally led to anaphylactic shook the last time I ate a small amount, so it is good to know the relationships. I think I will just avoid mangoes, as all our family are very allergic to poison ivy, etc.

    • Hi Norma,

      So sorry for this very tardy reply. I am sad to hear you had such a traumatic reaction to cashews. This cashew/mango/pistachio/poison oak/ and poison ivy family can be quite challenging and even life threatening for some. Since you had such a serious reaction, you probably ought to avoid all of the nuts and plants in this family. When eating at restaurants, be sure to ask about ingredients, especially in Asian or vegetarian/vegan restaurants where nuts are often part of the cuisine. With mangos, it’s often the skin that contains the problematic oils that cause allergic reactions for some people, but it’s best to be cautious and avoid them. Here’s to a healthy and safe life without the cashew/mango family!

      Zel

  5. reizaal aziz said

    Hi, just to share some experience and insights on cashew and mango alergic reaction.

    I live in the tropic where we have a lot mango variety and probably a few cashew variety. The edible parts are eaten raw or cooked/pickled. The cashew shoots are often eaten as fresh salad.

    However particular care has to be taken while handling or harvesting the produce to avoid prolong contact with the sap. Cashew fruits used in cooking are usually boiled and strained, sometimes repeatedly. Although a really tree-ripe cashew fruit taste sweet, juicy and fragrant, it would leave your tounge and lips feeling unpleasant. Sap that stuck on your lips causes blisters. Cashew nut shells are throughly grilled over fire, preferably in a tin can filled with dry leaves and at times, loosely covered with a big lid cause the shells may explode and flew and hit you with the black booling sticky sap making a mark on your skin for days, or on your shirt forever. But I guess that’s what little kids do.

    There are a few exceptional variety of mango that cause blisters on the skin as well. The tree bark exudes lots of sap when broken, also from the thick skin of the fruit, but becomes less when ripen. The skin must be peeled generously thick to avoid that unplesant taste on your tounge. The fresh fruit is visually unappealing because of the dirty dried sap on the skin. These mango variety are never commercially exported. They are consumed locally as they have slightly different texture, taste and smell.

    Thanks.

    • Hi Reizaal,

      Thank you so much for your informative comments about cashews and mangoes. I’m aware both cashews and mangoes grow in tropical climates where many varieties we never see commercially are available locally. Your comments inspired me to do some research on the processing of cashews, since they pose quite a challenge to safely separate them from their very hard shells in order to avoid burning the hands when they come in contact with the natural oils or sap. I hope to share some intriguing information about the cashew shell oil on this blog in the near future.

      I’m curious to know where you live.

      All the best,

      Zel

  6. gary gough said

    Hello!

    I have been experiencing the mango reaction for a few years now, but I only get it on my lips. It feels sort of like really badly chapped lips with what feels like a bit of numbness and a bit of itching at different times. I don’t get the full body rashes right now, but I’m so afraid that it will grow into a life threatening issue that I just don’t eat Mango anymore, and its too bad because its literally my favorite fruit. Regarding Cashews, I hadn’t had any issue until very recently, now it appears that i get the same reaction on my lips as when i eat mango. Too bad, because wouldn’t you figure that Cashews are my favorite nut!

    • Hi Gary,

      I totally understand how frustrating it is to have to avoid mangoes and cashews, especially because mangoes are in season right now! What I’ve observed with both my husband and my son, who were experiencing similar symptoms from eating mangoes and cashews, is that by avoiding them completely for nearly a year, they were able to tolerate a small serving of mango occasionally–with several weeks between tastings. At other times, my husband would break out on his legs, chest, and back with an itchy rash that also made his skin feel hot. We, too, were concerned that it might become a life-threatening issue at some point, but our dermatologist said it was unlikely. He explained the skin reaction was pesty and uncomfortable, but not likely to send anyone to the hospital. Those with a severe nut allergy that sends them to the emergency room with anaphylaxis, must consider nuts and nut products to be life threatening throughout their lifetime. Because pistachios are in the same family as mangoes and cashews, I would avoid them, too. Take heart, though, there are many, many other delicious fruits and nuts to enjoy!

      Enjoy good health–eat lots of fruits and veggies,

      Zel

  7. Dana said

    XUrushiol is found in Cahews, Pistachios and Mangoes as far as food items. But I am curious if anyone gets the same reactions with raw Carrots? I do and I am convinced the skin has urushiol but cannot findany literature to back this up.

    • Hi Dana,

      Apparently you have an allergic dermatitis when coming in contact with raw carrots. However, it’s not caused by urushiol, which is only found in cashews, pistachios, mangoes, poison oak, poison ivy, and sumac. There were a few studies done on people who worked in a factory where they were processing raw carrots and suffered from skin irritation. They problem disappeared when they stopped handling raw carrots for some time. It might help to wear gloves while peeling carrots, and then try cooking them. If you still have the irritation, carrots are not your best friend. Best to avoid them. The studies I looked at were brief, so I don’t know the culprit that causes the dermatitis. You’re fortunate that you can identify that raw carrots are responsible for causing the skin problems. Many people suffer for many months, or even years, without being able to find the cause.

      Zel

      • Dana said

        Thank you. In my research, I have found that avocados and certain type of mushrooms also have urushiol.

      • pennytwain said

        Where did you find that avocado and some mushrooms have urushiol? And do you know what types of mushrooms? I knew about mango, cashew, and pistachio and their connection to urushiol because I am highly allergic and end up with basically poison ivy inside me from my lips to the end of the system if I eat mango (and last week cashew for the first time) but avocado was my first food allergy and I never found a connection. This is the first time that I’ve read that it included avocado. I was just prescribed an epipen by my allergist because the cashew one swelled my throat so badly and it hurt all down my esophagus (still does almost a week later), but he had never heard of this before me. I told him I had researched it so he looked it up and confirmed I was right. He’d been practicing 40 years and had never seen it before. So I’d really like to avoid any mushrooms that might have the same affect if you can point me in the right direction

      • Hi Penny,

        Can you tell me which post on my NutGourmet blog mentioned avocados and mushroom containing urushiol, so I can adjust it? I’ve looked all over and have somehow missed it.

        While avocados do not contain urushiol, they do contain latex that often causes unpleasant allergic reactions. Other fruits that contain latex include papaya, bananas, and kiwis. The mushroom connection to urushiol involved wild mushrooms growing in a poison ivy or poison oak area. Some of the leaves of the poison plants may have brushed against the mushrooms, coating them with the oil. You’re wise to avoid eating or handling foods in the mango family–prevention comes first. Good health to you!

      • pennytwain said

        Not sure which one. That was a couple of weeks ago (Sorry, I haven’t been on Word Press since then). I just did a Google search and found it that way

  8. My daughter & I are possibly experiencing this RIGHT NOW. We’re both very allergic to poison ivy, and she woke up today with swollen, chapped lips. I developed the tingling lips later in the day. It took me a few minutes to make the connection to the new package of cashews we had bought this Saturday. Since I’ve eaten cashews before with no reaction, I was wondering what it might be. My guess is that this batch of cashews wasn’t processed properly.

    Your article was very helpful, so thank you! It seems like there’s no more mangoes or cashews for us anymore!! I’ve had a sore tongue reaction in the past from pistachios, and certain kinds of white wine too, and am also allergic to mushrooms. This connection is very obvious now that there is a connection.

    • Hi Kimberly,

      I was just cleaning out my inbox and realized I had overlooked your email. Shame on me. Hopefully by now you’ve come to terms with the cashew-mango family. What my husband found is that by avoiding them, he can occasionally have a serving without a reaction, though sometimes he will develop the itchy rash. It’s rather unpredictable, but generally, by avoiding the whole family (cashews, pistachios, mangoes, poison oak, poison ivy, and even sumac, he and my son, who also has this allergic tendency, stays symptom-free. I’ve also
      learned that mushrooms and avocados may contain urushiol oil, the irritant that causes so much distress.

      Zel

    • pennytwain said

      Are you allergic to specific mushrooms or all mushrooms? I am wondering because I have an increasingly severe reaction to avocado, mango, and cashew, so I am trying to find out what else to avoid now that I am at epipen level

  9. loki said

    I am highly allergic to poison ivy. But I eat mangos with the skin on all the time – I make a salad with them – Thai type with green mangoes. I have no problems with this. Also no issues with pistachios either.

    • Hi Loki,

      Thanks so much for your comment. You’re fortunate that your allergic reaction is limited to just poison ivy. That’s pretty easy to avoid by taking careful precaution. Lucky for you that you can enjoy the other members of the poison ivy family (poison oak, mangos, cashews, and pistachios). A note of caution though–you may possibly have a reaction if you binge on those other foods. Hopefully, you can continue to enjoy them without a problem.

      Zel

    • pennytwain said

      Also, be aware that you can suddenly develop a reaction to those things where you haven’t had one before. I’ve eaten cashews for years without incident but suddenly last week they almost sent me to the hospital (actually probably should have gone but I hate hospitals). And with mango, it took me a long time to make the connection because I’d never had a problem with mango before that so I just thought I was somehow reinfecting myself with poison oak for a long time

      • Hi Penny,

        Yes, I am aware that foods you’ve enjoyed often can suddenly bring on an allergic reaction. That food becomes the straw that breaks the camel’s back. You’re right, it doesn’t have to be a big binge. My husband had been eating cashews as a nighttime snack for years without a problem. While we were visiting my son in the Philippines, we were eating mangos every day, sometimes cut into chunks and sometimes we were eating them off the skin. Handling the mango skin (that contains urushiol oil) and putting on socks resulted in a raging rash around his ankles. When we returned home, my hubby snacked on cashews one night. The next day his chest and back were all broken out. The mango family also includes cashews, pistachios, poison oak, poison ivy, and pink peppercorns. People rarely make the family connection, but now you do. Share the information with your family and friends–it could save lives.

        Zel

      • pennytwain said

        I didn’t know about the pink peppercorns. Thanks for the heads up! I’ll be sure and watch out for them. Yeah, I was devastated to discover the mango allergy and disappointed about the cashew one, but more so because I’m trying to be vegan and it seems so many vegan recipes have either avocado or cashew in them!

  10. Vinaya said

    I always got adult acne after eating cashew and mango ( not raw only ripe) and in India this attributed to the fact that these are heat inducing foods. Any cooling food taken along with mango used to bring down the acne. I now wonder if it is allergic reaction,

    • Hi Vinaya,

      Hard to say, but it hints that cashews and mangoes may be allergenic for you. Often, children outgrow food allergies, though not always. The key is how you react to these foods today as an adult.

      Zel

  11. Mads said

    I’ve seen cosmetics and lotions that have mango seed butter as an ingredient. Is there any chance that the allergenic oil could be in the seed butter? Should I avoid any product with the butter if I’ve had acute contact dermatitis from mango in the past? I’ve searched the internet high and low and haven’t been able to find any information about whether mango seed butter is a safe ingredient for people with this allergy. I’ve read to avoid the skin of the fruit and the sap, but can find no warnings about the seed.

    • Hi Mads,

      If you’re quite sensitive to mango, it might be safest to avoid mango seed butter. The mango skin contains urushiol oil–that’s the culprit that causes so many allergies to the mango family that also includes cashew, pistachio, poison oak, and poison ivy. In the process of manufacturing it’s possible that the mango flesh and the seed might come in contact with the oil in the skin. How about considering aloe gel or coconut oil in place of mango seed butter. These contain many beneficial vitamins and minerals and offer healing benefits.

      To your good health,

      Zel

  12. Dustin Ginsberg said

    I grew up eating mangoes, especially Haden mangoes, as my grandfather had a tree in his yard, when we would visit our father in South Florida in the summer, and never had an allergic reaction to eating them. Sometime in the early 1970s, I believe, when I was perhaps in my early 20s, I came upon vacant lot that had a mango tree with a lot of mangoes, both on the ground and also ones I could knock off the tree. As it was summer I happened I have my shirt off, and no bag to carry the mangoes to the car, so I made several trips cradling the mangoes in my arms against my body. Needless to say, some of the mangoes that I had knocked off the tree were still oozing sap. I guess within hours of carrying the mangoes against my skin, I developed a rash on my chest around the solar plexus.This was the day before I was to head back up to the northeast, and I brought a suitcase full of these mangoes with me. The rash persisted even though I washed the area thoroughly, and applied cortisone cream. After week it was still there, and I went to the drugstore and talked to the pharmacist about it. He asked me if I was still eating the mangoes, and I said I was, and he said to stop eating them because I had become sensitized to them. A day or so after I stopped eating them the rash disappeared. I never had any other allergic reaction after that from eating mangoes, except if, when I actually moved into the house with the mango tree after my grandparents we’re no longer there, in season I sometimes ate three or four mangoes a day, and while I didn’t get an allergic reaction, tended to feel toxic from all that being in my system, but I have to say, eating a good mango, especially the original Haden mango, is the most euphoric I get from eating food.

    • Hi Dustin,

      Thanks so much for sharing your interesting history with mangoes. Because my husband and two of my sons have this mango allegory, I’ve been able to see first hand what causes a reaction. When they’ve stayed away from the whole family (cashews, pistachios, and mangoes for several months, they can eat a few pieces of mango without any major reaction. It’s when they eat a whole mango or have mango several days in a row, that they break out in a rash on their ankles, chest, and back. My youngest son finds that it affects his mouth and makes it feel slightly numb. My husband has the rash when he eats cashews or pistachios. That food family also includes poison oak and poison ivy. They goodness, we haven’t had contact with those, but for sure, it could be a nasty reaction.

      My observation is that even though you’re not eating from the or handling the skin–that’s the part that has the very allergenic urushiol oil–your body is sensitive to the oil. Very sensitive people will also react to the mango flesh, even though they haven’t handled the skin. Your body is letting you know mango is probably something you ought to avoid. I totally understand that’s going to be difficult. Mangoes are really delicious, but it’s clear they are not your friend. You might also be observant about possible reactions to cashews and pistachios. Usually, if you’re allergic to one, you will have a problem with the whole food family. Hope you feel better soon.

      Zel

      • Dustin Ginsberg said

        Hi Zel,

        I guess your son inherited his sensitivity from his father. That reaction I got was a long time ago, over 45 years ago. I do eat cashews and recently have been eating shelled pistachios, and don’t have any problem with them. At one point in the early 1970s I was on vegetarian diet for about a half year and for protein I ate about a pound of raw cashews a day and didn’t have any problem. Nor have I had any allergic reaction to mangoes before or since that, although I make sure to wash my hands after handling them. I don’t get to eat as many as I used to when I lived near a juice bar and they got fresh local mangoes, but for about the first time ever recently, a few that I got from the supermarket turned out to ripen okay. Usually they are picked too green, and some in my second supermarket batch we’re like that, and also if they are cooled below 50° or 55° (the packing box they come in states not to do this), they will never continue ripening when they are warmed again, unlike most other fruits.

        There is the idea which has been floated since the 1960s, that one often craves things one is allergic to. Maybe that idea is a carryover from such things as narcotics, but I don’t know that it is true. However cashews, pistachios and mangoes can be sort of addicting but I don’t know if it’s related to their allergenic qualities. But then again you could throw in chocolate and Reese’s Peanut Butter Cups, coffee, and whatever else. I think sometimes it’s just people with self-depriving and/or obsessive/compulsive personalities making up rules for others similar to how religion is perpetuated. I’m being sarcastic here, but…

  13. Win said

    Hi Zel ,just stumbled across your info about the mangoes and cashews while checking what is meant by the internal heat which we hear about in traditional Indian and Chinese medicine.Lip eruptions and upset stomach due to eating too many mangoes are quite common in India and are attributed to internal heat .Never knew that the skin had allergens .We generally tend to not peel them and just cut them upturn the skins and eat them …rarely using a spoon .Guess on the whole we have a strong immunity to them .Have not heard of rashes from handling them .The cashew processing info is known to people who live in the cashew bearing areas and I was told about it by someone though other people again don’t know about this and on the whole nut allergies are very uncommon in India.

    • Hi Win,

      Thank you so much for your comment. I find it interesting to learn that even people who live in mango growing countries and eat them often can develop an allergic reaction to the urushiol oil in the skin of the mango. For people who are highly sensitive, even the mango cut away from the skin can have traces of the troublesome oil. When I read about the terrible allergic reactions suffered by people working with cashew processing, my heart goes out to them.

      In my own family, my husband ate cashews frequently for years without a problem. It was only when we visited our son who lives in the Philippines and we were eating mangoes every day that my husband developed a severe reaction. So glad to hear nut allergies are rare in India–not so in the U.S. where nut allergies are fairly common.

      Zel

      • Dustin Ginsberg said

        Zel, a little update on mango reactions. In the last couple of months I’ve been trying to find some decent mangoes at the supermarket and I found a few, surprisingly, but I also tried some of the precut mango slices packed in plastic containers. These are not fully ripe, but I enjoyed them in a sweet-tart sort of way. One day I ate nearly the whole container, and a number of hours later I had gastrointestinal distress and abdominal pain, although it didn’t last too long. That is the first time I ever got that from mangoes and I believe it was because I ate more than little bit of unripe mangoes–I don’t usually eat mangoes that are not fully ripe, and I believe unripened mangoes have more of the allergens.

      • Hi Dustin,

        Sounds like you overdid a good thing. Actually, unripe mangos have many benefits. They contain high levels of enzymes effective in tenderizing meat. They also contain high levels of vitamin C helpful for maintaining blood vessel elasticity and good for producing new blood cells. Green mangos help cleanse the intestines and helps clear bacterial infections. Now for the bad stuff–Eating too much unripe mango can cause throat irritation, indigestion, dysentery, and abdominal colic. Seems you suffered from the intestinal distress. Fortunately, green mangos are not poisonous–just don’t overdue it next time you’re tempted to buy heaps of mangos on sale.

        Here’s to good health,

        Zel

  14. Win said

    Hi Zel Someone had asked about mushroom in the comment thread .My Husband had an extremely severe reaction to eating lightly sauted Shitake Mushrooms …whiplash like red marks on the entire body and severe itching for about 10 days …researching his symptoms I came across the information that raw or lightly cooked Shitske mushrooms can have this severe allergy .A scientist Friend from a horticulture institute said that in fact all mushrooms should always be well cooked .

    • Hi Win,

      Thank you so much for sharing your husband’s experience with eating lightly sautéed shiitake mushrooms. I’ve not done any research on mushrooms, but I am aware that mushrooms should always be well cooked because they may contain properties that can cause bad reactions. Now that you’ve stirred my curiosity, I’ll do some mushroom reading. Thanks so much –I love to research!

      Zel

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