If you are allergic to nuts you may have been told to avoid chestnuts along with all the other nuts. You may never have even eaten them in your life. But do you need to continue avoiding them?
What are chestnuts?
The definition in dictionary.com explains: “any of the several deciduous trees constituting the genus Castanea, of the beech family, having toothed, oblong leaves and bearing edible nuts enclosed in a prickly bur, and including C. dentata (American chestnut), which has been virtually destroyed by the chestnut blight, C. sativa (European chestnut), C. mollissima (Chinese chestnut), and C. crenata (Japanese chestnut).” It also includes the fruit and wood of the tree and the horse chestnut or conker tree.
Chestnuts are part of the Fagaceae family of trees, along with beech and oak.
The Anaphyalaxis Campaign share information about allergy to sweet chestnuts here. They discuss how this allergy is likely linked to cross reactivity or oral allergy syndrome where someone reacts to some pollens and fruits and also to some nuts. It could also be lipid transfer proteins (LTPs) reactions. Check out this blog, Allergy, Oral Allergy Syndrome or Lipid Transfer Protein reaction?
Allergy to chestnuts is rare but it can cause serious reactions in rare cases.
Are all nuts from the same family?
I found a very easy to understand definition on Wikipedia “Nuts are a composite of the seed and the fruit, where the fruit does not open to release the seed. Most seeds come from fruits, and the seeds are free of the fruit, unlike nuts such as hazelnuts, hickories, chestnuts and acorns, which have a stony fruit wall and originate from a compound ovary.” It’s worth reading this definition in more detail. I hadn’t realised for instance that most nuts in the culinary sense, such as peanuts, brazil nuts etc. aren’t nuts at all.
The complexities of nut allergies
You can have anaphylaxis to ground nuts and tree nuts and also have cross reactivity to other food groups like legumes and seeds. Some people can be allergic to just one nut type while others are allergic to them all. I am allergic to peanuts for instance, which itself isn’t actually a nut at all, it’s a legume which is in the same family as peas and lentils. However, I’m also allergic to most of the other nuts, including pine nuts, but interestingly not almonds. The protein make-up is very similar which is why the body treats them the same. But like all allergies, it’s complex and people can differ greatly in which nuts they are allergic to the severity of their reactions.
Watch out for chestnuts at Christmas time
If you are all allergic to chestnuts the Christmas festivities should have you on high alert. You can find chestnut in turkey stuffing, Brussels sprouts are also often served with flaked chestnut or almonds to added flavour. They are also used in many baked goods and more so in foods made for the Christmas market. They may also be roasted by street sellers during the winter so if you have an airborne nut allergy steer well clear of these.
Cross reactions with chestnut and latex
Chestnut allergy is also linked to latex allergy and I’m also allergic to latex so that’s probably the likely link here. If you have a latex allergy this could explain why you also react to chestnuts and vice versa. If you are allergic to latex, check out Latex allergy #101.
Keep children away from conkers and horse chestnuts
The Anaphylaxis Campaign also advise caution even where conkers or horse chestnuts are concerned for someone with peanut allergy. I’ve never had a reaction to conkers despite many playground battles. The difficulty is that no two people are the same – we all have slightly different reactions to different foods. All very confusing.
Should a person with a peanut allergy exercise caution, even though chestnuts aren’t directly related to other nuts? For now caution is the buzz word and with good reason. I made plans to ask my allergy dietician and request tests for chestnut as well as lupin just to be on the safe side.
My allergy to chestnuts and how it started
I have always been allergic to peanuts, cashews, hazelnuts and other nuts but I’d never knowingly eaten chestnuts, so how do you know if you might react?
What I did was get some allergy tests done at my allergy hospital, which came back negative. This isn’t necessarily a green light to say you’re never going to be allergic though, as I found out to my cost, and it’s interesting to observe how it became an allergy.
I don’t seem to come across chestnuts in ingredients lists that much in my everyday life, but once I thought they would be OK I did some careful testing. A local cafe used to make lots of lovely freefrom cakes using chestnut flour. I asked to try a tiny bit and nothing happened. I first put a bit on my lip and waited. Then took a tiny bite, and still nothing. My nut allergies are immediate, fast moving and devastating so this clearly seemed to indicate I wasn’t allergic to chestnuts. Don’t do this at home unless you are sure of what you’re doing and have sought your doctors advice. This was the advice they gave me, do it at home and slowly. I’m not sure this always wise but it’s the usual advice if tests come back negative. You can, and should however, request observed introductions at hospital. That seems far safe to me and I know many, especially children are offered this when reintroducing allergens people have grown out of.
The fateful cookery course and the chestnut flour
The same cafe ran a cookery class to learn how to make the amazing cake you see above, so I booked onto that and learnt so much. Looking at that photo I can still taste the cake, it was so good. Well anyway, to cut a long story short, I took the cake home and we slowly polished it off with no allergic reactions.
However… and ironically, it was on the day I ate the last slice it all went wrong.
I managed to eat almost the whole cake with no reaction
I took it out on a walk and when we stopped for a drink in a pub garden, I ate the last slice of this amazing cake. I felt OK, just a bit snotty, my nose began to run. I thought nothing of this at first but then we started walking, up a very steep hill. I wasn’t worried at first, but as walked further I began to feel very off. I had hives all over my scalp but not the rest of my face. I also had hives and swelling, strangely and at the time embarrassingly as I didn’t know what was going on at first, under my arms in my armpits and all in my genital region.
Very weird hives in very weird places
I had thought maybe I needed the toilet but when I crept into the bushes and pulled down my trousers it was clear something was amiss down there!
It was then that I thought this was an allergic reaction. My breathing was fine though and I didn’t feel like I was having an anaphylactic reaction, but I was disorientated and confused. We had my adrenaline with us but on that occasion I just took some antihistamines and sat down for some time. The swelling eventually went down and we continued on our walk but I was walking really slowly and very concerned that it might all start up again, as it often can do.
Now I am allergic to chestnuts
Suffice to say I am now allergic to chestnuts but it took a whole ass massive cake to get me sensitised and allergic. I also cut this cake up and froze quite a bit of it so it was also happening over a prolonged time.
I now avoid all chestnut related products and now realise the sense in the advice to avoid all nuts, even if you’re not allergic to all of them.
Strange aside, I can eat almonds… and continue to include almonds, in small and regular quantities in my diet. I buy almond milk every now and then and eat free from foods with almonds in them, my favourite being the Free From chocolate brownies you can get in Waitrose which are AMAZING.
And finally, water chestnuts…
Thank goodness, the Chinese water chestnut (Eleocharis dulcis) is most definitely NOT a nut, it’s a grass-like sedge grown for its edible corms. It grows in marshes, underwater in the mud, so stir fries are safe – water chestnuts are our friends.
You may enjoy reading: Should a nut allergic person avoid water chestnuts?
So yes, you probably should avoid chestnuts if your nut allergic
So, the answer to the question is probably, yes, you should exercise caution where chestnuts are concerned. No restnuts choasting on my open fire – not since reacting to a cake made with chestnut flour. I don’t even know what chestnuts taste like on their own. What do they taste like? Are they nice? Are they nutty? Anyone out there with a chestnut allergy?