Reduce Allergies in Your Child During Pregnancy with Your Diet!

Inside passage, Canada

Hello! Our move to the east allowed us a little travel through the beautiful Inside Passage. I miss those mountains terribly. Alas, I’m holding out for the pretty fall of Virginia.

Today we’re chatting allergy prevention in babies.

Within the prenatal series happening around the blog is a focus on nutrition. Some women don’t realize that what you eat during pregnancy can have an effect on your child’s allergies after they are born. How crazy and also very cool is that fact?!

In my last position, I got to work with some of our pediatricians a lot more closely than my previous positions as a nurse midwife. I learned loads from them but specifically, I learned a lot about food allergies from one provider that went on the specialize in pediatric dermatology.

When I started to look into the evidence, there’s actually quite a bit. And more so, how much of this education are women hearing during their pregnancy? If I had to guess, not a lot.

Let’s dive in.

Twenty years ago, the United Kingdom’s medical officer for Toxicity of Chemicals in Food made a poor recommendation. The officer recommended that mothers without a peanut allergy should avoid consumption of peanuts and products containing peanuts to avoid a peanut allergy in their baby. Well, that sounded like a good idea. The problem is that when a mother eats her body makes an immune response to that food, something called immunoglobulins, and these immunoglobulins pass through the placenta and to the baby during pregnancy (Fujimara et al., 2019).

The result of the medical officer’s recommendation to avoid peanuts during pregnancy resulted in the highest prevalence of peanut allergies in 4 to 5 year old children. Avoidance was causing more harm than good (Fujimara et al., 2019).

What evidence is there for a protective effect when pregnant mamas eat certain foods while pregnant or breastfeeding?

  • A study of 6,288 children in Finland demonstrated that eating/drinking milk products in pregnancy resulted in a lower risk of an allergy to cow’s milk in mothers not allergic to milk (odds ratio: 0.30; this means in this study, the mothers than ingested cow’s milk were 70% less likely to have a child with a milk allergy because they ingested milk during their pregnancy). This specific study found immunoglobulin A in the cord blood samples of children who did not have milk allergies. This finding supports that the maternal ingestion of milk helps produce an immune system response during pregnancy that protects the child from a future milk allergy (Fujimara at al, 2019).
  • A study of 8,205 children between 10 to 14 years old found that children of the mothers who ate peanut or tree nuts at least 5 times a week during pregnancy were 69% less likely to have a peanut allergy. An important note in this study was there was not a protective effect observed in mothers who were already allergic to peanuts or tree nuts. The reduction in peanut or tree nut allergy risk was only noted in pregnant women not previously allergic to peanuts or tree nuts (Fujimara et al., 2109).
  • A cohort study in the United States examined 1,277 mother-child pairs and found a number of factors that reduce allergy and asthma in children. This study in particular demonstrated that early exposure to allergens in the first or second trimester of pregnancy may contribute to tolerance rather than contribute to allergy development in children.
    • Ingestion of peanuts in the first trimester by pregnant women was associated with a 47% less likelihood of peanut allergy in the child.
    • Ingestion of milk during the first trimester was associated with a 17% less likelihood of asthma and a 15% less likelihood of allergic rhinitis.
    • Ingestion of wheat in the second trimester was associated with a 36% less likelihood of atopic dermatitis (Fujimara et al., 2019).
  • Breastfeeding mothers who consumed peanuts while breastfeeding and who introduced peanuts to their child before 12 months of age had reduced incidence of peanut allergy in their children (only 1.7% of population demonstrated a peanut allergy). Mothers that waited until their child was older than 12 months or avoided peanuts altogether had a 15.1% and a 17.6% increased risk of peanut allergy in their children (Fujimara et al., 2019).

If you are a woman with an allergy to peanuts, there is good news as well. The LEAP trial, a randomized controlled trial published in the New England Journal of Medicine in 2015, found that introducing peanuts to infants at higher risk for peanut allergy reduces the incidence of peanut allergy (Fujimara et al., 2019)! You can check out the LEAP study here. The study is currently looking at how long children have immune protection after exposure to peanuts and if there are other parent characteristics that could contribute or impact peanut allergy development.

Dietary supplements can also contribute to lower likelihood of asthma in childhood. Two studies (Vitamin D Antenatal Asthma Reduction Trial and the Copenhagen Prospective Studies on Asthma in Childhood) have examined Vitamin D supplementation during pregnancy and found that children of women who ingested 2,400 to 4,000 international units of Vitamin D daily during pregnancy had a 25% reduced risk of developing asthma or recurrent wheezing from ages 0 to 3 years (Fujimara et al., 2019).

Maternal intake of fish oil supplements or a diet of oily fish has been shown to offer protective effects against asthma and wheezing in children, as well as a reduction in atopic eczema and allergy to eggs.

Another area of great interest is the microbiome – the microbes that make up the intestinal gut in a newborn baby. The route your baby is born into the world may affect their propensity to have an allergy. Babies born via cesarean section have higher incidences of atopic dermatitis, rhinitis, asthma and eosinophilic esophagitis. Babies born vaginally are exposed to microbes in the birth canal and demonstrate more protection than babies born via cesarean section (Fujimara et al., 2019).

As always, when you review evidence you should always ask: “What’s the clinical application?” or “What’s the takeaway?”

  • If you’re a provider, consider offering education about the possible benefits of eating nuts, milk and wheat in pregnancy. Tailor recommendations to a woman’s allergies and reactions.
  • If you’re a pregnant mama or planning a pregnancy, consider incorporating these foods into your diet on a regular basis during pregnancy.
  • If you’re a breastfeeding mama, consider eating peanuts while breastfeeding and introducing peanuts to your child before 12 months of age.

Example: Pick up the mixed nuts next time you’re at the grocery store. A serving of nuts is also a great afternoon snack!

If you’re interested in how to introduce peanuts to your baby, this is a great video…

My middle babe has eczema and I had no idea about when to introduce peanuts to him!

What guidance have you received during your pregnancy regarding nutrition? In my experience, there’s very little education about nutrition and the benefits for infants – definitely an area to improve!

See you Friday for the Five!



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1 year ago on the blog…Friday Five (#22)

Links in the post

How to Introduce Peanuts to Your Baby:

LEAP study:


Fujimara, T., Zing Chin Lum, S., Nagata, Y., Kawamoto, S., & Oyoshi, M.K. (2019). Influences of maternal factors over offspring allergies and the application of food allergy. Frontiers in Immunology, 10. doi: 10.3389/fimmu.2019.01933

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