Last Updated October 6, 2006
Peanut allergy research: from plant to pill
Researchers are working on several fronts to prevent peanut allergies and limit the potentially deadly reactions they can cause.
The efforts include attempts to breed peanuts missing the offending allergy-causing proteins; an experimental drug to lessen allergic reactions; and marketing alternatives to peanut butter.
People with food allergies usually have an antibody called immunoglobulin E in their blood, allergists say. Those who are allergic have a genetic predisposition to the condition.
It's estimated more than 150,000 Canadians suffer from peanut allergies. About two per cent of people can have an anaphylactic reaction to an allergen, and peanut allergies account for 50 to 100 deaths in the United States every year.
Anaphylactic shock is an explosive overreaction of the body's immune system. It starts with swelling, difficulty breathing, cramps, vomiting and diarrhea, and can proceed to coma and death.
In July, pediatric allergists in the U.S. reported about 23 per cent of children will eventually outgrow their peanut allergies.
The U.S. Department of Agriculture is working on growing a natural, hypoallergenic peanut. Scientists at the department have screened 300 varieties of peanuts in a quest for one lacking one of the major allergens, a protein that triggers allergies.
They say the NC 4 peanut lacks a protein called vicilin or Ara h 2, the leading allergen.
Removing allergens Ara h 1 and h 2 would reduce the number of people affected by peanut allergy by up to 50 per cent, according to Soheila Maleki, a chemist who led the discovery of the NC 4 peanut.
The problem is there are 14,000 varieties of peanuts, so finding one without the two allergens is like finding a needle in a haystack. Other researchers are using genetic engineering techniques to "turn off" the allergens in peanuts. Even if they succeed, parents will still have to ensure only "safe" peanuts make it into their kids' sandwiches and snacks.
A shot against deadly reactions
Developing drugs to raise an allergy sufferer's tolerance for peanuts is another avenue of research.
One such experimental drug, TNX-901, may work as a preventive treatment not a cure. The monthly shots work by blocking a chemical pathway involved in food allergies.
Researchers tested three different doses of the drug and a placebo on 84 people.
They found those who received the highest dose could handle an average of about nine peanuts' worth of peanut flour, compared to the equivalent of half a peanut at the beginning of the study.
The study was paid for by one of the drug's developers, with grants from the U.S. Peanut Board and the Peanut Foundation of the National Institutes of Health in the U.S.
The drug is on the fast track for approval in the U.S. but three companies with rights to TNX-901 are involved in a legal dispute over it.
If approved, patients would need to take lifelong shots of the drug. The drug may offer a safety zone against accidentally eating peanuts, but people would have to remain cautious and continue to carry life-saving shots of epinephrine in case of exposure.
Activated charcoal and non-peanut butter
Canadian doctors say people with peanut allergies may be able to drink activated charcoal after accidentally eating peanuts.
Their experiment, which was done in lab dishes, suggested charcoal binds to peanut allergens. Theoretically, it should hide the allergens from an over-active immune system.
Also, Canadians have invented an alternative to peanut butter called "peabutter." It uses dried peas, vegetable oil and sugar. Almond butter is another option. These solutions are only viable if the products are made in peanut-free facilities.
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