by Megan Garcia

The topic of food avoidance and a healthy pregnancy diet comes up a lot because I work with mamas who eat paleo, AIP, or “real food” that may not include things like grains, legumes (peanuts, holla!), and dairy.

But during pregnancy, these allergenic foods are also information for baby’s immune system.

And as it turn out, food proteins may help to build up baby’s tolerance.

Tolerance means that the body accepts them and doesn’t mount an immune response, which is what we see with sensitization or allergy.

Common allergens for babies include peanut, cow’s milk, and egg.

Hint: Avoiding allergens doesn’t work

As far as we know, avoiding allergens or following a limited pregnancy diet will not protect baby’s immune system.

According to the American Academy of Pediatrics, this is true whether or not baby is “high-risk” and has an immediate family member with allergies. Instead, we are seeing evidence that a limited diet might do just the opposite and increase the risk of food allergies. Food allergies often include eczema.

This is worth talking about.

Because it wasn’t too long ago when doctors recommended that high-risk mamas restrict allergenic foods during pregnancy and while breastfeeding. The idea was that it would protect baby from the development of allergies.

Why allergens may have a place in your pregnancy diet

We know that the proteins in food have the potential to tone and educate baby’s immune system.

For example, researchers found that drinking cow milk products during pregnancy might protect little ones from developing cow’s milk allergy, especially those babies of non-allergenic mamas.

And in an interesting study published in 2014 in the Journal of Allergy and Clinical Immunology, researchers looked at mama’s diet during the first and second trimesters.

They found that a higher intake of allergenic foods during early pregnancy was associated with a lower risk of allergies and asthma. For example:

  • Eating peanuts during the first trimester was linked to a 47% reduction in odds of childhood peanut allergy.
  • Drinking milk during the first trimester was associated with reduced odds of asthma and allergic rhinitis.
  • Eating wheat during the second trimester was associated with reduced risk of childhood eczema.

But how is this possible? What’s going on with baby’s immune system during pregnancy?

Well, we know that baby’s immune system is functional at 16 weeks. And by 22 weeks, the fetal immune system is capable of mounting an immune response.

In a recent review, researchers from Utrecht University questioned whether or not this hinted at a crucial time window of time for baby to acquire tolerance.  

A healthy pregnancy diet is inclusive

During pregnancy, your immune system does a little dance.

The first trimester is marked by inflammation (this helps with embryo adhesion). Then in the second trimester from week 13 to week 27 it is characterized by an anti-inflammatory environment. So any ongoing proinflammatory signals or infection during this time can affect the stability of the pregnancyBy the third trimester, your immune system swings back to a more inflamed state (Th1 type dominated, to be specific). And this is ideal because it supports labor and delivery.

When it comes to allergen exposure, this dance may work in baby’s favor.

In real life, this means that you might be able to eat foods that you typically need to avoid. Mama, I’m not suggesting that you eat gluten if you know that your body will forever reject it in the most gnarly way possible – for example, in the case of celiac disease. However, if you avoid gluten (or any other food) out of principle and can generally eat it, then you may want to work that food into your diet during pregnancy and while breastfeeding.

The idea here is diversity.

You want a wide range of foods, flavors, and information to come into your body and begin training your baby’s immune system so that it’s flexible and tolerant.

Be inclusive when you can.

And of course, maintain those Whole30 standards of quality. This means shopping for food that’s minimally processed, organic when it makes sense, and sourced from farms that care about how their animals are raised.

You know the rules.

Whole30 isn’t a diet

Whole30 is a reset. It’s for 30 days. And it’s about your relationship with food. This includes how food makes you feel.

When it comes to allergens, the science isn’t conclusive. But we’re seeing it lean towards the direction of a “healthy” pregnancy diet that doesn’t exclude foods.

With all the veggies, eggs, and grass-fed protein, Whole30 gives an excellent framework for a healthy pregnancy diet that’s worth maintaining during pregnancy and beyond. Based on the current research, you may want to consider doing Whole30 during your last trimester since early pregnancy might be a time when you want to include allergens.

Just a thought.

Ultimately, do what works for you. Get neutral with food. And stay curious, #becausefoodfreedom.

While it’s safe to say that refined vegetable oil and some food additives (hello, Red40) are forever best avoided, your little one might be okay with grains or cow milk.

That’s tolerance. And it’s a good thing.


megan garciaMegan Garcia is a mama to two boys and lives in Los Angeles. She has a master’s degree in Traditional Chinese Medicine and is the creator of First Foods & Beyond. Her interest in baby health, combined with a big love for all things food and gut related, has become the heart and soul of what she does in her own little corner of the web, at megangarcia.com.