I am a new mother, and I have a family history of eczema and asthma. I am breastfeeding my baby. Which foods should I cut out of my diet to prevent allergies in my child?
Common sense suggests that if there is a family history of allergies, a mom who breastfeeds should avoid the ingestion of common foods associated with allergies such as milk, eggs, nuts, and fish. But common sense and scientific studies do not always end up on the same page.
Previously, experts have suggested that lactating moms with infants at high risk for developing allergies should avoid peanuts, tree nuts, eggs, cow milk,and fish from their diets while nursing. Based on further research, these suggestions are no longer true.
In the January 2008 edition of Pediatrics, a position statement was published concerning the effects of early nutritional interventions on the development of allergies in infants and children. The experts who crafted this paper consisted of pediatricians on the Nutrition and Allergy Committees of the American Academy of Pediatrics. These experts also consulted with the Canadian Pediatric Society, the FDA (US Food and Drug Administration), CDC (Centers for Disease Control), and the National Institutes of Health.
In other words, when doctors make recommendations, which may impact the way a pregnant or lactating mom eats in order to prevent allergies in their babies, they never make it based only on individual studies. Instead, a wide variety of published data are reviewed and double-checked by people with wisdom on how nutrition may impact the development of allergies.
Here are some of the highlights of the position statement mentioned above, based on current evidence:
- At the present time, there is a lack of evidence that dietary restrictions during pregnancy play a significant role in the prevention of conditions such as asthma, eczema, or food allergies.
- Avoiding certain foods such as eggs, fish, nuts, and milk during lactation does not prevent allergies later in life, with the exception of atopic dermatitis (eczema).
- Breast feeding exclusively for at least 4 months decreases the incidence of eczema and cow milk allergy, but only for the first 2 years of life.
- Exclusive breastfeeding for at least 4 months protects against early wheezing. There is no convincing evidence that exclusive breastfeeding protects against asthma occurring beyond 6 years of age.
- If a mom breastfeeds but supplements with formula, it may be wise to not use a cow milk formula or a soy-based formula if there is a high risk of allergies given a family history. Instead, a hydrolyzed formula (the protein in the formula is either fully or partially broken down to make it less allergenic) may be the better choice. The experts noted that not all partially or fully hydrolyzed formulas have the same effects; some may work better than others, but who decides this remains highly controversial.
What about the issue of when to introduce solid foods? The experts recommend that solid foods not be introduced before 4 to 6 months of age. In Calgary and the rest of Canada, parents have been told that solids should not be introduced before 6 months of age.
There are some gastroenterologists and allergists who see very little difference between introducing solids at 4 months or 6 months. Nor do they think that the 6 month ideal will prevail as more and more research pours in. Furthermore, most experts agree that delaying the introduction of solids beyond 6 months has no significant protective effect on the development of allergies, regardless of whether infants are fed cow milk protein or human milk.
Being a doctor who has only worked with infants, children, and adolescents for the past 25 years, I take these recent expert opinions with a grain of salt. Here is why: position statements often evolve in contradictory ways.
For better or worse, expert opinion needs a review every 4 to 5 years. It never stays the same; it changes back and forth constantly. And it always ends with the words "additional studies are needed". The recent statement, predictably, concluded that additional studies are needed to document the long-term effect of dietary intervention in infancy to prevent allergies, especially in children older than 4 years and in adults.
What does this mean practically to the parent of a child at high risk for allergies?:
- There is very little data that restricting ones diet during pregnancy helps to prevent allergies.
- Breast feed exclusively for at least 4 months.
- If there is a high risk for allergies and you supplement with a formula, do not use a cow milk formula or a soy formula.
- Do not introduce solids before 4 to 6 months.
Finally, remember just because there is a lack of evidence that restrictions work, the use of restrictions - as dictated by common sense - should not be disproved either. I doubt we will ever see a paper about a baby whose mom did not eat peanuts during pregnancy and suffered damage as a result! The opposite may, however, be true one day.
Currently, there are 800 plus articles on allergy prevention when one uses the search box at www.aap.org. A similar search on the Canadian Pediatric Society’s site (www.cps.ca) failed to find any additional information.
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