5 common food allergies: How much is enough to trigger a reaction?

Turns out, the threshold for the most sensitive of people varied depending on the ingredient. John Moore/Getty Images

TORONTO – Peanuts, seafood and celery. They’re common food allergies but what amount is the baseline to trigger an allergic reaction in even the most sensitive diners?

These days, food labels often include warnings such as “may contain nuts,” or “trace amounts” of a common ingredient tied to allergies. In a new study, British scientists hoped to learn how much of a certain food could trigger an allergy attack.

University of Manchester researchers identified five of the most common food allergens that cause allergic reactions – peanuts, hazelnuts, celery, fish and shrimp. Depending on the severity of the allergy, people can tolerate different amounts of the food in question.

READ MORE: What doctors are warning about parents about allergies and asthma in kids

“What we wanted was to find a level of allergen which would only produce a reaction in the most sensitive 10 per cent of people. This sort of data can then be used to apply a consistent level of warning to food products,” Dr. Clare Mills, who led the research, said.

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“What we’d like to see are warnings which tell people with allergies to avoid certain products completely or just apply to those who are most sensitive,” she explained.

READ MORE: Did dated recommendations contribute to spike of food allergies in kids?

Mills and her team worked with 436 people who had allergies. They were given small doses of the food they’re allergic to while the doctors monitored their reactions.

Turns out, the threshold for the most sensitive of people varied depending on the ingredient:

  • Between 1.6 and 10.1 milligrams – or 1/1000th of a gram) of hazelnut, peanut and celery protein produced a reaction
  • 3 milligrams of fish was enough to elicit a reaction
  • 5 grams of cooked shrimp caused a reaction, but the researchers note that raw shrimp could have a different effect

READ MORE: Groups say babies may eat allergy-sparking foods as early as 6 months

(Leo Kavanagh/Global News)

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The Manchester-based doctors say that the number of people with food allergies has increased in recent decades to about five to seven per cent in kids and about two per cent in adults.

Their findings were published Monday night in the Journal of Allergy and Clinical Immunology.

Last year, research about allergy attacks triggered by pesticides on produce surfaced.

After eating an orange, a U.S. toddler went into anaphylactic shock – the first time such a case has been reported, according to doctors.

READ MORE: Can pesticides trigger allergic reactions? They did in a rare Canadian case

This isn’t the first peculiar incident recorded in North America. In September, Canadian researchers reported on a 10-year-old Quebec girl who had a severe allergic reaction to a slice of blueberry pie.

In that case, they warned that you might not be allergic to the food at hand, but the pesticides on the produce might trigger a bad reaction.

“As far as we know, this is the first report that links an allergic reaction to fruits treated with antibiotic pesticides,” lead author, Dr. Anne Des Roches, said in a statement.


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