Food allergies and Fungus
We regularly get people telling us about improvements made to their quality of life after avoiding certain foods – often those containing fungi (e.g. mushrooms, cheese, brewed drinks, bread, soy sauce, Miso and many more). Others find there is no difference whether they eat those foods or not. So what is actually known about food allergies in aspergillosis patients, or even those who are only allergic to the fungus Aspergillus rather than have an infection?
Firstly, it is important to note that very little is known about the influence that food has on the health of people predominantly living with allergies caused by breathing in allergens. Almost nothing at all is known about those caused by Aspergillus itself, so what follows are merely comments based on three or four research papers.
Do food allergies exist?
NHS introduce the subject as follows:
A food allergy is when the body’s immune system reacts unusually to specific foods.
Allergic reactions are often mild, but they can sometimes be very serious.
In young children, common food allergies include milk and eggs. In adults, allergies to fruit and vegetables are more common.
Nut allergies, including peanuts, are relatively common in both school-age children and adults.
Symptoms of a food allergy can affect different areas of the body at the same time. Some common symptoms include:
An itchy sensation inside the mouth, throat or ears
A raised itchy red rash (urticaria, or “hives”)
Swelling of the face, around the eyes, lips, tongue and roof of the mouth (angioedema)
Read more about the symptoms of food allergies.
In the most serious cases, a person has a severe allergic reaction (anaphylaxis), which can be life threatening.
If you think someone has the symptoms of anaphylaxis – such as breathing difficulties, lightheadedness, and feeling like they are going to faint or lose consciousness – call 999, ask for an ambulance and tell the operator you think the person has anaphylaxis or “anaphylactic shock”.
NHS also make the following important point about food intolerance:
What is food intolerance?
A food intolerance is not the same as a food allergy. People with food intolerance may have symptoms such as diarrhoea, bloating and stomach cramps. This may be caused by difficulties digesting certain substances, such as lactose. However, no allergic reaction takes place.
Important differences between a food allergy and a food intolerance include:
The symptoms of a food intolerance usually occur several hours after eating the food
You need to eat a larger amount of food to trigger an intolerance than an allergy
A food intolerance is never life threatening, unlike an allergy
Read more about the differences between food allergy and food intolerance.
There are many myths about food allergies and intolerances – can you tell fact from fiction? And what is the difference between the two?
If we are allergic to allergens we breathe in, can this cause us to become allergic to certain foods?
There are several non-fungal examples of this – one of the most common is developing an allergy to a particular pollen (something we can’t avoid breathing in) e.g. birch or ragweed pollen and this leading to an allergy to certain foods e.g. apple, nuts. This can be a serious allergy leading to anaphylactic shock. The reason for the allergy to the food is that our immune system fails to be able to tell the difference between the pollen and the fruit and therefore triggers a response based on cross reactivity of the two allergens.
Do fungi cause food allergies?
Not commonly when eaten as far as we know – and considering how much we eat them, that might be a surprise. However, they do cause a lot of allergies when we breathe them in, and of course when we have a chronic infection such as allergic bronchopulmonary aspergillosis (ABPA) and severe asthma with fungal sensitivity (SAFS). There are very few descriptions of people becoming allergic to inhaled fungi and also reacting to certain foods:
- Allergy to the fungi Alternaria and Cladosporium (both extremely common outdoor airborne fungi) have been shown to cross react with spinach and mushroom.
- In another case, eating the fungal-based food Quorn (made from Fusarium) triggered an allergic reaction based on cross reactivity of a Quorn allergen to an allergen in airborne fungi that the patient was allergic to – there are anecdotal reports of more cases of this type of allergy but only very few.
- Sunflower seed-fungus syndrome was thought to be an example of respiratory symptoms that could be exacerbated by eating a food (sunflower seeds). However, it turns out that nearly all of the allergy was linked to the action on peeling the seeds with the teeth rather than eating the kernal. It is presumed that the increase in symptoms was linked to inhaling the fungal spores on the nut husk while peeling!
Could inhaled Aspergillus/ aspergillosis cause a food allergy?
There is no published work that describes this happening, but several of the papers already described mention that Aspergillus can cross react with other fungi including Cladosporium, Alternaria and Fusarium. This suggests that Aspergillus could very rarely cause food allergies such as we have described for the other three fungi, but we have no evidence that they actually do. Much more work is needed in this area of allergy research before we can make firm conclusions, but perhaps if you feel that your respiratory or gastric symptoms worsen when you eat certain foods then a visit to your doctor to explore this possibility is a good idea.
What about food additives & enzymes manufactured using Aspergillus? Could they be causing allergies?
Aspergillus and other fungi are used to manufacture several different food additives, vitamins, medicines and industrial enzymes. It is impossible to answer this question without information about how much – if any – fungal antigen is present in these products, but it is thought to be a low risk as product purity is an important part of the industrial process. At the moment we have no information to confirm this.
Resources referred to:
- Herrera-Mozo I, Ferrer B, Luís Rodriguez-Sanchez J, Juarez C. Description of a novel panallergen of cross-reactivity between moulds and foods. Immunol Invest. 2006;35(2):181-97.
- Hoff M, Trüeb RM, Ballmer-Weber BK, Vieths S, Wuethrich B. Immediate-type hypersensitivity reaction to ingestion of mycoprotein (Quorn) in a patient allergic to molds caused by acidic ribosomal protein P2. J Allergy Clin Immunol. 2003 May;111(5):1106-10.
- Lara S, Sobrevía M, Bartolomé B, Marqués L, Alcoceba E, Almacellas J, Marín JP. Description of Sunflower Seed–Fungus Syndrome. J Investig Allergol Clin Immunol. 2015;25(6):449-51.
- US Food and Drug Administration: Microorganisms & Microbial-Derived Ingredients Used in Food (Partial List)
- Health Canada: List of permitted food enzymes
- AGRICULTURAL MICROBIOLOGY By D. J. BAGYARAJ, G. RANGASWAMI 2005 Microbial Biotechnology p388-405