"Patients are still languishing in a time bomb-like existence, where a mouthful of the wrong food could mean death."
Credit: JONATHAN BURTON/Nature
LONDON: The best way to prevent food allergies may be to expose babies to high-risk fare rather than avoid it altogether, according to evidence from ongoing clinical trials.
Several groups of scientists are testing the theory that exposing a baby to foods like peanuts repeatedly at an early age will allow the immune system to tolerate them, and prevent an allergic reaction later in childhood. If successful, this could have significant implications for the 8% of children in the Western world that currently suffer from food allergies.
Twenty years after the death by anaphylaxis of a 15-year-old volunteer in a study on peanut injection immunotherapy, allergist John Oppenheimer, University of Medicine and Dentistry of New Jersey, who led the inital study, is "sad that patients are still languishing in a “timebomb-like existence” where a mouthful of the wrong food could mean death, though he is heartened by recent research progress," wrote journalist Rebecca Kessler, author of a review of the studies published today in Nature Outlook.
An immunological cocoon
Until recently, mothers of babies at high risk of reactions were advised to avoid eating potential allergens during pregnancy and only to introduce these items when the child reached three years of age.
However, in 2008, research comparing the incidence of peanut allergies in Britain and Israel found that Jewish children were 10 times less likely to suffer from the condition, despite eating significantly more food containing peanuts during early life. This led scientists to question whether they had been advising the correct approach. Both the American Academy of Paediatrics and the UK Department of Health revised their recommendations, concluding there is now insufficient evidence to support restriction in a child's diet.
"The idea was to wrap the infant up in a sort of immunological cocoon, and not expose them to proteins that could launch allergic reactions," said Gideon Lack, professor of paediatric allergy at King's College, London, and co-author of the 2008 study. "But there is a possibility that we were achieving the reverse of our intentions through this avoidance policy,"
Leaping forward
Lack has since begun a clinical trial to determine the best approach. The Learning Early About Peanut Allergy (LEAP) study, which began in 2006, is following 640 children at high risk of developing the condition to discover whether avoidance or consumption is more successful.
The first group of children will be prevented from eating peanut-containing foods until the age of three, whilst the second group are fed a peanut snack three times a week. During this time, the researchers will monitor changes in the children's immune systems, and an allergy test at age five will be used to determine which of the two strategies has a better outcome before the end of the trial in 2013.
Increasing tolerance
A second group of researchers, led by Wesley Burks from the Duke University Medical Centre in North Carolina, U.S., has also tested the consumption technique in a pilot study of 25 peanut-allergic children. The subjects were exposed to incremental doses of the allergen, a technique known as oral immunotherapy.
"We have shown that with oral immunotherapy, patients will tolerate more peanuts before they have an allergic reaction," explained Burks. In fact, as outlined in Nature Outlook, after one year of treatment the children in the test group were able to eat the equivalent of 20 peanuts, whereas the average tolerance in the control group was a single nut.
Treatment or cure?
This increase in tolerance corresponds to a significantly reduced risk of a fatal anaphylactic reaction. Apart from the obvious consequence for sufferers, this would be extremely valuable in countries such as the U.S. where the cost of treatment and lost productivity is estimated to exceed US$500 million.
However, Burks emphasises there is currently little evidence that tolerance will persist after the regular dose is discontinued. "We have not shown that this type of treatment will make the allergy go away permanently," said Burks.
Further research is therefore essential to determine the full potential of the treatment, and to ensure it is suitable for use outside a controlled trial. U.S.-based organisation Food Allergy Initiative (FAI) is campaigning to raise funding for a large-scale phase III clinical trial, which if successful could lead to approval for widespread use within seven years.
Prevent food allergies
The mother should be eating these suspect food while carrying the child and not wait until the child is born!
Just because the parent doesn't like a certain food, believes its not a healthy choice is wrong thinking.
Eating these foods exposes the child before the child is born and exposes the child to these foods at an earlier age allowing the child to develop a resistance to any allergy.