An “explosion” in a food allergy poses a particular risk to vegans and vegetarians, one of Britain’s leading experts has warned.
Cases of pollen food syndrome (PFS) have risen markedly in recent years as a result of global heating, worsening pollution and changes in pollen patterns, Dr Isabel Skypala said.
Attacks of PFS are usually triggered by eating raw nuts, fruit and vegetables. However, they can also be prompted by foods popular among people who avoid animal products, such as soya milk, avocados, jackfruit, edamame beans and smoothies.
The estimated 13 million Britons who are allergic to pollen, especially birch tree pollen, and suffer from hay fever are most at risk. PFS is caused by unstable pollen antibodies found in proteins in some raw – but not cooked – fruits and vegetables, nuts and soya.
Skypala, the only consultant allergy dietician in the NHS, said: “The last research into the prevalence of PFS in Britain, which I undertook in 2008, showed that 2% of adults had it, including 4% of people in London. I suspect that it has probably doubled since then.
“In my clinic at the Royal Brompton hospital in London about five out of every 10 people I see has PFS, whereas 10 years [ago] it might have been two. There’s a perfect storm of increasing PFS at the same time as you have a very great increase in people eating fruits and vegetables.”
It is someone’s inherent sensitivity to pollen, rather than the fact they follow a meat-free diet, that puts them at risk, added Skypala.
Most sufferers experience only mild symptoms such as itching or tingling in or around their mouth. However, growing numbers experience nausea, vomiting and even difficulty breathing because their throat swells up. “While a lot of people with PFS are having a mild reaction, severe reactions are more frightening and more dangerous,” she said.
Skypala said PFS sufferers often end up very nervous about what they eat. “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.”
The surge in cases is adding to the pressure on the NHS. However, specialist services are under-resourced so patients often wait months to be seen, she added.
Skypala has drawn up a new set of clinical guidelines for the British Society for Allergy and Clinical Immunology. These also advise doctors how to differentiate PFS from a nut allergy, with which it is often confused.
The Anaphylaxis Campaign said foods that can trigger PFS include raw apples, pears, kiwi fruits, strawberries, plums, cherries, cherry tomatoes, celery and carrot. Frozen fruit or vegetables can still provoke a reaction, and peeling potatoes or other root vegetables can lead to itching or swelling in the hands and eyes.
“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 charity added.
Margaret Kelman, a specialist nurse at Allergy UK, said: “The psychological effect of having PFS, especially where multiple foods are being avoided, can not only greatly restrict the diet but also can lead to anxiety and fear, and impact on an individual’s ability to carry out daily tasks.”
Sufferers should stop eating the trigger food, rise their mouth with water, take an antihistamine medication if they find that helps, and try eating some of the foods baked or roasted instead, she added.