Don't let allergies drive you nuts

Natasha Salmon cannot be in the same room as a bowl of peanuts without getting wheezy. The last time she ate satay sauce, she was struggling to breathe after only a mouthful.

“It was five or six years ago and I was in a Thai restaurant,” she recalls. “I accidentally ate some satay [made from peanuts]. Within seconds my face, lips and airways were completely swollen. I used the adrenalin pen that I always carry with me in case of a severe allergic reaction. But my friends had to call an ambulance and I was ill for about a week.”

Natasha’s allergy to peanuts first developed when she was just five, and her symptoms have grown worse over the years. The 21-year-old journalism student from Farnham in Surrey developed an allergy to raw fruit and vegetables at 15, and recently has suffered swelling of her lips, face and throat after eating salad foods such as lettuce, celery and cucumber.

“I can’t begin to describe how much I miss a fresh, crisp Golden Delicious,” she says. “In the winter my allergies are less severe and I will treat myself and eat just the skin of an apple. I’ll manage it by taking an antihistamine and putting Vaseline on my lips. But there is no doubt that my allergies are getting worse. My immunologist can’t explain why, though it’s thought to be related to my hay fever. I just have to deal with them and hope they subside.”

Food allergies such as Natasha’s have risen sharply over the past 20 years, with 1-2 per cent of adults and 4-6 per cent of children thought to be affected. The number of children admitted to hospital for food-related anaphylaxis (a life-threatening allergic reaction) has risen seven-fold since 1990 – but no one quite knows why.

The latest theory, published in the Annals of Allergy, Asthma and Immunology last week, suggests that chemicals called dichlorophenols could be to blame. US researchers who looked at food allergies in more than 2,000 people found that those with the highest levels of dichlorophenols in their urine had an 80 per cent higher risk of having a food allergy.

Their theory is that dichlorophenols, which they say are found in purified tap water and in pesticides and disinfectants, have anti-bacterial properties that could affect the microflora in the gut that are thought to protect against food allergies.

So should we stick to organic fruit and veg and substitute tap water for the bottled kind? Not just yet, according to Jonathan Brostoff, professor of allergy and environmental health at King’s College London. He says the study has several flaws, not least the fact that it classified people as having a food allergy by using a blood test that is only 50 per cent reliable. Food allergy diagnosis is a complex area, he says, and hard to diagnose without a clinical interaction with the patient.

“Another problem is that the study didn’t publish its results on how many people with the lowest levels of dichlorophenols tested positive for food allergy,” he adds. “It might be possible that these chemicals affect the balance of the immune function and the risk of food allergy, but we would need far more data to show cause and effect.”