Oral Allergy Syndrome Is On The Rise – And It's Causing Reactions To Raw Fruit And Veg

Those with hay fever are the most at risk.
Aleksandr Zubkov via Getty Images

Raw food allergies are on the rise and pose a particular risk to vegans and vegetarians, one of Britain’s leading experts has said.

Pollen food syndrome (PFS) – also known as oral allergy syndrome – is a hypersensitivity reaction to certain fruits, vegetables and nuts when consumed in their raw form.

Cases have increased significantly in the last few years as a result of global heating, worsening pollution and changes in pollen patterns, Dr Isabel Skypala, the only consultant allergy dietician in the NHS, told the Guardian.

Around 13 million Brits who are allergic to pollen – especially birch tree pollen –and suffer from hay fever are considered high risk.

PFS is triggered by unstable pollen antibodies found in proteins in some raw fruits and vegetables, nuts and soya. However, it isn’t an issue when these ingredients are cooked.

What is raw food allergy?

If you are susceptible to allergies you can become sensitised to airborne pollens by breathing them in. This is most commonly seen with hay fever.

But many plant-based foods – fruit, vegetables, nuts and cereals – have a protein structure that is very similar to the pollen in trees, grasses and weeds.

PFS is hypersensitivity reaction to certain raw fruits, vegetables and nuts which usually causes mild symptoms. But it can also be caused by foods popular among people who tend to avoid animal products, such as soya milk, avocados, jackfruit, edamame beans and smoothies.

Other foods that can trigger PFS include raw apples, pears, kiwi fruits, strawberries, plums, cherries, cherry tomatoes, celery and carrot, the Anaphylaxis Campaign said.

As well as this, frozen fruit or vegetables and peeling potatoes or other root vegetables can lead to itching or swelling in the hands and eyes.

What are the symptoms?

Symptoms of PFS usually occur within five to 10 minutes of eating the allergic food. Most people who suffer from PFS will only experience mild symptoms, but more troubling symptoms an include:

  • Itching
  • Nausea
  • Vomiting
  • Difficulty breathing as their throat swells up

“While a lot of people with PFS are having a mild reaction, severe reactions are more frightening and more dangerous,” Dr Skypala said. “A PFS reaction, mild or severe, makes people extremely anxious, and they often cut out all fruit and nuts, because they are worried about having another reaction.”

According to Allergy UK, you may experience severe reactions if you:

  • Consume large amount of allergen in a short space of time such as nuts, soya milk, freshly squeezed juice and smoothies

  • Have allergies to several plant based foods

  • Have uncontrolled or asthma

Who is most at risk?

PFS affects about 2% of the adult population in the UK and is often linked to sensitivity to grass, tree or weed pollen. The people most at risk are those who suffer from hay fever. It’s someone’s inherent sensitivity to pollen, rather than the fact they follow a meat-free diet, that puts them at risk, Dr Skypala said.

Why has there been a rise?

“The rising prevalence of PFS comes at a time when there is a worldwide change in dietary habits, with more people adopting a vegetarian or vegan lifestyle. A vegan/vegetarian diet may also include soy and jackfruit, both of which can provoke severe PFS reactions,” The Anaphylaxis Campaign said.

The rise in cases is adding pressure to the NHS. But, specialist services are under-resourced so sufferers might have to wait months to be seen, Skypala said.

However, you should always seek advice from your healthcare professional if you are concerned you may have had an allergic reaction to a plant based food.