"We were shocked to find out that even in the first year of life, over 20% of infants with eczema already were sensitized [showed susceptibility] to peanut allergy," says Graham Roberts, MD, a pediatric allergist at King's College London.
"But we didn't know how early the peanut allergy started; we thought may at 3, 4, or 5 years of age," he says.
The new research suggests peanut allergy develop much earlier, Roberts says.
The study involved 640 infants aged 4-11 months with eczema.
The researchers measured blood levels of immunoglobulin E (IgE), an immune system protein the body makes in response to allergens. A positive result means a person is sensitive to and likely to be allergic to a certain food.
The results showed:
- 23% of the infants were sensitive to peanuts.
- 31% were sensitive to cow's milk.
- 22% were sensitive to sesame.
- 16% were sensitive to Brazil nuts.
- 20% were sensitive to hazel nuts.
- 21% were sensitive to cashews.
- 14% were sensitive to almonds.
Sixteen percent of the infants tested positive for more than four foods.
New Food Allergy Theory Being Tested
Roberts says this is the first step in an ongoing study designed to test the hypothesis that giving infants foods to which they are sensitized will prevent allergies later in life.
"Right now, people are told to avoid the food they're allergic to. Our hypothesis is that by introducing the food into the diet early on, the body will see it as normal and won't become allergic to it. We're questioning a fundamental preconception," he says.
In the ongoing study, infants with eczema who test positive for sensitivity to peanuts are being divided into two groups; half get peanuts in their diets and half don't. The researchers will compare the rates of peanut allergies in the two groups when the kids reach school age.
Results are expected in three years, Roberts says.
The hypothesis is supported by the fact that Jewish children in London are about 10 times more likely to have peanut allergies than Israeli children "and one of the biggest differences is that kids in Israel are introduced to [peanuts] early in life," says Hugh Sampson, MD, professor of pediatrics, allergy and immunology at Mt. Sinai School of Medicine in New York.
"This is an important study testing whether high-dose early exposure to foods is protective [against allergies]. It's a good theory, but one of several," he tells WebMD.