Food allergies seem to be everywhere, but there is a certain segment of foods that can cause allergic reactions and aren’t as commonly discussed as nuts, dairy, or even wheat, which gets a disproportionate amount of attention given the fraction of people who actually have a diagnosed gluten intolerance or allergy (Celiac’s not withstanding). No, I’m talking about fruits. There are a wide variety of fruits that can actually trigger an allergic reaction, and fruits, more than common food allergens, are rarely diagnosed by themselves. Bananas highlight this unique phenomenon that is known as cross reaction allergies.
In bananas, the enzyme chitinase (ky-tin-ace) is a primary allergen. Chitinase isn’t exclusive to bananas and can be found in other fruits such as avocados and kiwi. Chitinase is a multipurpose enzyme divided into 5 classes: plant, mammalian, insect, fungal, and bacterial. It’s used to break down glycosidic bonds in chitin (ky-tin), a main component in exoskeletons of insects and crustaceans, and the cellular wall structure of fungi. It’s also a very important polysaccharide in plants and organisms used to digest and break down chitin of other organisms and fungi or to rebuild and reshape its own chitin. Chitinase intolerance is even used in medical research and in the agriculture industry, so as you can see there is a plethora of uses for this enzyme!
Class I chitinase, aka plant chitinase, is a major allergen found in not just bananas, but avocados, and chestnuts as well. These fruits also have hevein-like proteins. These proteins are similar to pro-hevein, a protein that helps create the milking/coagulation of latex. Why is this worth mentioning? It is a key component to what causes cross-reactivity allergies from the aforementioned fruits.
Speaking of cross reaction allergies, this is what makes fruit allergies some of the more unique in the allergy world. Similar enzymes can sometimes link not only other fruits but also seemingly unconnected things together, and latex allergies are one of many like this. Latex allergies are linked to allergies of other foods like as bananas, chestnuts, mangoes and melons. It’s further (and perhaps better) explained on “The Doctor’s Laboratory” as:
“Individuals with reaction to specific allergens to foods, inhalants or substances can be known to develop allergy to others and it is becoming better recognized that reactions are occurring to different foods containing either the same allergen, or an allergen with a very similar protein structure. Reactions can be either light or heavy and this is known as allergic cross-reactivity. “
Cross reactivity is fairly common with latex and fruits or vegetables (known as latex-food syndrome), but cross-reactivity isn’t exclusive to food (though these tend to be the most common). Birch pollen allergies can lead to developing an allergy to celery, apples or even kiwis, a common allergen in Europe (especially in Scandinavia). Even dust mite allergies can bring on seafood allergies, and while these are rare, the connections exist.
It’s interesting to see how plants and pollens can be similar on a molecular level even though they aren’t even in the same family or kingdom. Practically speaking, it can also be pretty helpful for those with allergies to better understand and avoid cross reaction allergies.
Getting back to bananas, it’s likely best to steer clear of masks and other products that contain latex. All of our allergy masks such as Respro, Vogmask, and I Can Breathe masks are all latex free and suitable for anyone with latex allergies, AND those who might also be allergic to bananas!
To learn more about latex allergies or about cross reactivity.