New Ways to Fight Nut, Milk Allergies
Studies Show Peanut-Rich Diets During Pregnancy and Injection-Free Milk Immunizations May Help
Can a Peanut a Day Keep Allergies Away?
Vivian Hernandez-Trujillo, MD, an allergist at Miami Children's Hospital, in
Florida, says that pregnant women with allergies often ask what they can do to
protect their babies from developing allergies "and we really don't know
what advice to give."
As a step toward finding out, researchers at Mt. Sinai School of Medicine in
New York City studied pregnant mice with peanut allergies.
Some of the mice were fed small amounts of peanut protein while they were
pregnant and breastfeeding, the idea being to increase their tolerance to the
nuts. The other mice were fed a normal diet.
After birth, the baby mice were given escalating amounts of peanut protein
for five weeks in an effort to further sensitize them to peanuts. Doctors call
this oral immunotherapy.
At the end of the study, the researchers "challenged" the pups with
a larger serving of peanuts, to see if it would evoke an allergic
Almost all the babies born to mothers who ate a normal diet had allergic
reactions, the study showed.
In contrast, only two of eight mice whose mothers ate a nut-rich diet during
pregnancy and breastfeeding had allergic responses, and both were mild.
"The results are fascinating and thought provoking," says
Hernandez-Trujillo, who moderated the session at which the studies were
Peanut Oral Immunotherapy
The best way to avoid food allergies is, of course, to simply avoid the
But that's not as easy as it sounds and accidental ingestion is common, says
Scott David Nash, MD, an allergist at Duke University.
For years, allergists have used immunotherapy, which includes the ubiquitous
allergy shot, to combat allergies to insect
stings and nasal allergies.
Nash's team tried another tactic: oral immunotherapy. They gave 20 children
with known peanut allergy escalating doses of peanut protein in the form of a
flour mixed into applesauce or other food. Once they reached a daily dose of
300 milligrams, about the equivalent of one peanut, they stayed on that dose
for four to 11 months.
At the end of the study, Nash's team challenged the kids with a hefty
serving of peanut flour. It contained nearly 8 grams of peanut protein, or the
equivalent of more than 13 peanuts.
"Nineteen of 20 (95%) of the patients were able to ingest the full
amount of the challenge, and most did not have any symptoms during the food
challenge," he tells WebMD. A few participants broke out in hives.
One person, who developed hives and airway tightening after the full dose,
was immediately and successfully treated with epinephrine.
Immune system changes from the start to the end of the study showed growing
tolerance to the peanut protein, Nash adds.
The long-term goal is buildup of enough tolerance so the food allergy
"goes away," says researcher Wesley Burkes, MD, chairman of the AAAAI
program committee and a professor of pediatrics at Duke University, Durham,
N.C. He also worked on the study.
"But for now we've shown that even though they have to keep eating the
food, the chance of having an accidental allergic reaction is less," he
More study is under way.