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
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.
While some studies do not show any protective benefit of breast feeding, the majority of them do. Overall, the data
appears to demonstrate a significant decrease in the risk of developing atopic dermatitis (eczema) with breast feeding.
The decrease appears to be even more dramatic in families that already have a history of food allergies.
Conclusion: Exclusively breast feeding for at least 4 months may help decrease the risk of atopic dermatitis and cow
milk allergy for the first 2 years of life. The benefits are greater for those who have a family history of allergic
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. The majority of
studies looking at food restriction during breast feeding do not show any benefit with the prevention of allergic
Conclusion: Diet restriction during breastfeeding may decrease the risk of atopic dermatitis in the first few years of
life. There is no clear evidence that food restriction during breastfeeding reduces the risk of food allergy.
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.
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
What About Probiotics?
Probiotics are defined by the World Health Organization as “live microorganisms which, when administered in
adequate amounts, confer a health benefit to the host”. One example of probiotics is bacteria used to make yogurt.
Probiotics can also come in the form of pills. They are sometimes recommended by physicians to help prevent
gastrointestinal problems when taking antibiotics. In theory, it would appear that probiotics could be helpful in
preventing allergic disorders such as food allergies. But what do the studies show?
The results are mixed. One published study demonstrated a reduction in eczema at 2 and 4 years of age, but no affect
on asthma or environmental allergies. Another study, published in January 2007, looked at the effect of feeding an
infant from birth to 6 months of age with probiotics. The researchers did not see any reduction in food allergies or
eczema in the infants who were given probiotics compared to those that were not. On the contrary, they found that the
infants who were fed probiotics were more likely to have positive skin tests to foods and environmental allergens such
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.
The following recommendations (based on the American College of Allergy, Asthma, and Immunology, the American
Academy of Pediatrics, and the European Society of Paediatric Allergy and Clinical Immunology) are suggested:
- Exclusive breast feeding for at least 4 months.
- IF there is a family history of food allergies AND the infant cannot be breast fed, use an extensively hydrolyzed
formula (Pregestemil, Nutramigen, or Alimentum). There is no evidence that soy formulas help prevent allergic
- Do no introduce solid foods until 4 to 6 months of age. There is no evidence that delaying foods such as cow's
milk, eggs, or peanuts beyond 6 months of age is useful in preventing allergic disorders such as atopic dermatitis,
food allergies, or asthma.
Updated 14 December 2009
Fiocchi et al. Primary dietary prevention of food allergy. Ann Allergy Asthma Immunol 2003;91:3-13.
Kramer et al. Effect of prolonged and exclusive breast feeding on risk of allergy and asthma: cluster randomized trial.
Von Berg et al. The effect of hydrolyzed cow's milk formula for allergy prevention in the first year of life: The German
Infant Nutritional Intervention Study, a randomized double-blind trial. J Allergy Clin Immunol 2003;111:533-40
FAO/WHO (2001) Health and Nutritional Properties of Probiotics in Food including Powder Milk with Live Lactic
Acid Bacteria. Report of a Joint FAO/WHO Expert Consultation on Evaluation of Health and Nutritional Properties of
Probiotics in Food Including Powder Milk with Live Lactic Acid Bacteria
Kalliomaki et al. Probiotics in primary prevention of atopic disease: a randomized placebo-controlled trial. Lancet
Taylor et al. Probiotic supplementation for the first 6 months of life fails to reduce the risk of atopic dermatitis and
increases the risk of allergen sensitization in high-risk children: a randomized controlled trial. J Allergy Clin Immunol
Fiocchi et al. Food allergy and the introduction of solid foods to infants: a consensus document. Ann Allergy Asthma
Greer et al. Effects of early nutritional interventions on the development of atopic disease in infants and children: The
role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed
formulas. Pediatrics 2008;121:183-191.
Lack G. Epidemiologic risks of food allergy J Allergy Clin Immunol 2008:121:1331-6.
Du Toit et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy
Clin Immunol 2008:122:984-91.
Nwaru BI et al. Age at the Introduction of Solid Foods During the First Year and Allergic Sensitization at Age 5
Years. Pediatrics 2009