Food allergy occurs when the body’s immune system wrongly identifies a food as a threat. When this happens, the body releases chemicals, such as histamine, in response. It is the release of these chemicals that causes the allergic symptoms.
The symptoms of a food allergy can come on rapidly. Symptoms can include:
The term for the more serious reaction is anaphylaxis. In extreme cases there could be a dramatic fall in blood pressure. The person may become weak and floppy and may have a sense of something terrible happening. This may lead to collapse, unconsciousness and – on rare occasions – death.
Most healthcare professionals consider an allergic reaction to be anaphylaxis when it involves difficulty in breathing or affects the heart rhythm or blood pressure.
If you suspect you have an allergy to any member of the legume family, it is important to see your GP. Your GP can refer you to an allergy clinic if needed. Your GP can locate an allergy clinic in your area by visiting the website of the British Society for Allergy and Clinical Immunology: https://www.bsaci.org/workforce/find-a-clinic/
At an allergy clinic, an allergy specialist will discuss your symptoms with you in detail. Skin prick tests and blood tests can help with the diagnosis. If your reactions are likely to be severe and you are at risk of anaphylaxis, you will be prescribed adrenaline auto-injectors (AAIs) for self-use in an emergency.
If you react to one member of the legume family, it is possible you could react to another member of this group. This process is known as “cross-reactivity” – where the proteins in one food are similar to those in another food.
Some people with a legume allergy will only react to that one legume, whereas others may react to other legumes as well. If you regularly eat other legumes with no symptoms, there would be no reason to suspect you will become allergic to them, however, always follow the advice of your allergy specialist.
It is difficult to determine how many people are allergic to multiple legumes, as studies show varying results. One study found that 5 out of 100 people with an allergy to one legume will also have an allergy to another legume. Other studies have higher estimates; however, this is highly dependent on geographical region and the prevalence of these foods in the diet in different countries.
The key message is to discuss any concerns regarding legume cross-reactivity with your doctor or allergy specialist. They will be able to give you specific advice regarding this and which foods you should avoid.
Top 14 allergens
Peanuts, soya and lupin are included in the list of top 14 major food allergens in the UK. This means they must be highlighted on food ingredients labels, for example in bold. For further information about peanut, soya or lupin allergy, see the link at the end of this article to read our individual factsheets.
The following list includes some other legumes that may trigger allergic reactions for some people. These are not included in the list of top 14 food allergens, which means they will be listed as an ingredient on food labels, but they will not be highlighted.
Read ingredient lists carefully every time you shop. When buying catered food, such as that sold in restaurants and takeaways, it is important to question staff directly. Staff may not be aware that legumes can cause allergic reactions. Make sure you name the specific legume or pulse that causes the problem.
More information can be found on our Factsheets webpage. If your legume allergy is diagnosed as potentially severe, you can read our factsheets on Anaphylaxis and Adrenaline in the General advice and information about anaphylaxis section.
See the factsheets on Soya, Lupin and Peanuts & Tree Nuts in the Food allergens factsheets section.