Prevention of Food Allergies - Can food allergies be prevented?
Over the past 20-30 years, the incidence of allergic diseases such as food allergies, asthma, and atopic dermatitis
(eczema) have increased dramatically. The incidence of peanut allergy has doubled in the last 10 years. While there
are some exciting new treatment prospects for food allergies, preventing them would be the ideal. Is this possible?
Here is the latest information on food allergy prevention:
Diet Restriction During Pregnancy
Several studies have looked at the theory that avoiding certain foods during pregnancy might help prevent food
allergies. None of these studies show that avoiding certain foods during pregnancy helps prevent food allergies. In
fact, some studies show the exact opposite. In one such study, mothers avoided cow milk and eggs from the 28th
week of pregnancy. It turns out that there were more egg allergic children in the group where mothers avoided eggs
and cow’s milk during pregnancy compared to the group that did not avoid anything.
Conclusion: there is no evidence that diet restriction during pregnancy helps prevent allergic disorders including food
Breast Feeding or Formula -- What is Best?
This has been a topic of debate since the late 1930’s when a study of 20,000 infants demonstrated that breast fed
infants had a sevenfold decrease in eczema compared to non-breast fed infants. While this study was not perfectly
done, it opened the door to more research and a number of studies have been published on the subject since that time.
Some of these studies have demonstrated that breast feeding is beneficial for the prevention of breast feeding, while
other studies do not show any benefit.
Conclusion: at this time there is no conclusive evidence that breast feeding, compared to formula feeding, reduces the
incidence of allergies, including eczema and food allergies
Diet Restriction During Breast Feeding
It is known that cow milk proteins, egg proteins, and peanut proteins will appear in breast milk when the mother eats
these foods. The question thus arises whether the presence of these foods in breast milk could lead to the infant
becoming allergic to cow milk, eggs, or peanuts.
One study compared two groups of children: One group had the mothers avoid cow milk, eggs, and fish for the first 3
months of breastfeeding. The other group had no diet restriction at all. The restricted diet group was found to have
less food allergies at 3 and 6 months of age compared to the no diet restriction group, but by 10 years of age there was
no difference between both groups. A study in 2003 in the New England Journal of Medicine found no association
with the consumption of peanuts while breastfeeding and the development of peanut allergy in infants.
Conclusion: The majority of studies looking at food restriction during breast feeding do not show any benefit with the
prevention of allergic disorders.
There are many different formulas to choose from to feed babies. This includes:
- Regular cow's milk formula (Enfamil, Similac,Good Start…)
- Extensively hydrolyzed cow's milk formula (Pregestimil, Nutramigen, Alimentum)
- Elemental Amino Acid formula (Neocate, EleCare)
- Soy formula
The difference between the regular cow's milk formula, extensively hydrolyzed, and elemental cow's milk formula has to
do with the processing of the milk proteins. The proteins in extensively hydrolyzed formulas are broken down in
smaller parts than regular formula. About 90% of cow milk allergic babies will be able to drink extensively hydrolyzed
formulas without problems. The few infants that cannot tolerate extensively hydrolyzed formula can use elemental
amino acid formula, which is broken down into even smaller particles.
Conclusion: The research demonstrates that there is no benefit in choosing a soy formula over a cow milk formula
when in comes to food allergy prevention. There is some evidence that cow milk formulas that have been
“extensively” processed (Pregestimil, Nutramigen, Alimentum) may offer a benefit in delaying the onset of food allergies
until about the 3rd year of life.
When should I introduce highly allergic foods such as peanuts in my child's diet?
For a long time, the recommendation was to avoid cow's milk until age 1, eggs until age 2, and peanuts until age 3 at
least, with the thought that delayed introduction of foods would avoid allergies. However, there is no evidence that
delaying the introduction of these foods prevents food allergies. In fact, it may just be the opposite!
For example, one study compared a group of Jewish children in the United Kingdom (where the introduction of
peanuts was delayed) vs. children in Israel (where peanuts were often introduced before 1 year of age). They found
that the prevalence of peanut allergy was 10 times higher in the children from the United Kingdom compared to the
children from Israel. There are other similar studies that also show that late introduction of solid foods was associated
with increased risk of food and environmental allergies.
Conclusion: There is no evidence that delaying the introduction of common food allergens such as cow milk, egg, or
peanuts beyond 4-6 months of age reduces the incidence of food allergies.
Updated 23 September 2013