Gut Health: A Game Changer in Pregnancy, Newborns, and Beyond

The vast majority of our immune system lives within our gut, and the entire foundation for gut health, which affects our overall health into adulthood, is laid in just the first 2 to 3 years of life! This is a critically important topic for new parents and desperately needs to be brought to the forefront of conversation as we look to give our children their best chance at a healthy life from day one. It all starts with the gut!

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Award-winning gastroenterologist and microbiome expert Dr. William Bulsiewicz, also known as Dr. B The Gut Health MD, is on a mission to educate the public on the critical importance of gut health. He spoke with us at The Mom Report to key us in on why gut health is something we need to pay far more attention to during pregnancy and our children’s early years.

Today we discuss how pregnancy and the days, weeks, and years following are a crucial time in the development of your child’s microbiome. In true Dr. B fashion, he shares some mind-blowing and incredibly underreported information that will forever change the way you think about the food you feed yourself and your family.

Why is it important for parents to pay attention to the gut health of their children?

I would make an argument that all health starts in the gut. We know that the gut plays a central role in regulating our metabolism, immune system, expression of our genetics, even our mood, energy levels and cravings. Now take all of this, and recognize that the entire foundation for gut health is laid during the first 2-3 years of life and the health consequences will echo into adulthood. We need to be sure to nurture gut health in our children if we want them to not only be healthy children, but even healthy adults.

What is the most important time for our children in the development of their gut health?

On the day a child is born, their gut is nearly sterile. You’ll notice that a baby’s poo doesn’t smell for the first few weeks. From nearly sterile at birth, a child will have a fully adult size gut microbiome by age 3, and potentially even before that.

When a baby is in utero, are there things that can impact their gut health before they are born?

Without question we know that the environment in utero, as controlled by Mom, has health implications for the sweet baby. While Mom’s microbiome is not yet transferring to the child, we know that Mom’s microbiome has a profound impact on the levels of nutrients and the amount of inflammation that the rapidly growing fetus is exposed to. It is for this reason that I strongly encourage a healthy diet during pregnancy, focusing on maximum diversity of plant foods, such as fruits, vegetables and whole grains.

What can pregnant women do to nurture a good environment for the development of their soon-to-be child’s gut health?

The most important thing is eating a clean diet. The ideal time to start eating clean is, honestly, today. Do it for yourself, and then when the time comes that you’re ready to have a baby, you’ll already have a healthy gut microbiome to transfer on to your baby. That said, if you’re already pregnant and questioning whether it’s too late, I’d encourage you to still follow through on making some changes. The goal here is to maximize the fresh fruits and vegetables in your diet. Ideally organic. If you consume animal products, do it on a limited basis to the greatest degree possible. And to the best of your ability, avoid processed foods.

Although a woman has little control over how their child is born, what impact does passing through the birth canal have on a child’s gut health?

Passing through the birth canal is Mom’s gift to her newborn child. It is the first major inoculation of the gut with Mom’s bacteria. Curious enough, late in the third trimester, Mom’s vaginal microbiome actually changes to resemble her gut microbiome. How cool is that!!! We know that children born by cesarean section are more likely to be obese, have asthma or eczema, or have diabetes. This speaks to the importance of fostering the microbiome early in life.

If you have a c-section, are there ways to get that good gut bacteria to our babies through breast milk?

Don’t worry if you had a cesarean section! Although we were hoping it wouldn’t be this way, my wife and I have had two children, both by c-section. And it’s still completely possible to foster healthy children with healthy guts in this setting. Breastfeeding is perhaps the most underrated thing we can do for our children. I can’t imagine a more perfect food, crafted through millions of years of evolution, designed to promote the vitality of a newborn. Our culture has missed the point on breastfeeding. We shouldn’t be limiting it to 6 months, or even a year. We should strive to continue as long as possible! I’m very proud of my wife, who provided breast milk to our children past 2 years of age. At times she had to work outside the box (outside the breast?!) by pumping and mixing it with almond milk.

The backbone of a healthy gut is the diversity of plant foods that you consume.
— Dr. William Bulsiewicz

What role does breast milk play in the development of healthy gut?

It’s absolutely huge. One of my favorite things about breast milk is that it contains something called human milk oligosaccharides (HMOs) that provide zero, yes literally ZERO, nutritional value to the baby. These are food for the gut bacteria. In other words, through the power of evolution Mom’s breast milk offers an energy source for the non-human inhabitants in baby’s gut. And it’s not just 1 or 2 types of HMOs. There are well over 100 different types identified so far.

Are there things mom can eat while breastfeeding that will help the child develop a healthy gut?

To me it once again comes back to Mom taking care of herself and her own microbiome first. If Mom is consuming a diversity of fruits and vegetables while she is breastfeeding then she is offering her infant baby those amazing phytonutrients to help maximize the health of that sweet little child.

What about formula that has pre- and probiotics added for moms that can’t breastfeed?

In a perfect world, if an infant can’t be breastfed then it would be ideal to have a breast milk donor. That said, formula that contains prebiotics as a substitute for HMOs are a good idea. Even if they can’t recreate the whole thing, our studies suggest they get pretty close and definitely achieve the effect of altering the gut microbiome in a positive light.

When our children start eating food, what are some foods that we can give them to help them develop and maintain a healthy gut?

From my perspective, what’s most important is what you don’t give them. When we introduce processed foods, meaning chicken nuggets and things of that variety, we are certainly not contributing to a healthy gut, and we may be damaging it. We all want our children to eat fruits and veggies, and this is where the food that Mom ate not only while breastfeeding and during pregnancy but even before pregnancy matters. For example, my wife has been vegetarian for years. That’s the way she ate for years before pregnancy, during pregnancy, and after while nursing. What would you know, my son LOVES plant foods. That’s because the microbiome forms your taste buds. If that’s the way you eat, you will eventually form a taste for it. What’s amazing is that my son will actually eat broccoli sprouts. They’re insanely bitter, but my wife ate them every day during pregnancy and now my son loves them.

What foods will negatively impact their gut health and why?

The same rules of gut health apply to both children and adults. The backbone of a healthy gut is the diversity of plant foods that you consume. There are very clear cut studies to support this. There are also clear cut studies to show us that drifting away from a plant based diet has deleterious effects on the gut. Our gut grows different bacteria to process animal products, and our studies show that those bacteria do very little to make us healthier but they definitely seem to promote inflammation. For this reason, we really need to moderate our animal product consumption, if we are including that in our diet. Processed foods are probably even worse. There are literally 5,000 – 6,000 chemicals in our processed foods, very few of which we know much about other than they didn’t exist until recently and now we are exposing our gut to them when we eat those boxed/bagged/packaged goods. I’m a big fan of striving towards a plant focused diet – whatever that means for you! We ALL have opportunities to do better!

What should a parent do if they are having great difficulty getting their child to eat fruits and vegetables? (Especially toddlers!)

Try to make it fun! Combine lots of different colors, which is fun and also great from a health perspective. Consider putting them on a kabob stick (make sure to get rid of the pointed tip) or cutting them into fun shapes. Include some nuts or whole grain popcorn along with the fruits and veggies. And probably the hardest part is just not ever getting started on the processed stuff. Once you give them chicken nuggets, they’re going to want them again.

In the past, you have mentioned the correlation between gut health and eczema in children. What would your advice be to all the parents out there struggling to soothe their child’s eczema?

I would have a very low threshold to introduce probiotics in a child with eczema. There are clear cut studies showing that probiotics are effective in eliminating infant eczema, and I can testify first hand because my son had horrible eczema until we started him on a probiotic. Then it went away in 3 days.




Dr. B has ventured well beyond the walls of his office and become an incredible resource to people across the globe, sharing gut health expertise through his popular Instagram account and insanely good podcasts.  He has made it his mission to help us understand the importance of having a healthy gut and the changes we can make to drastically improve our overall health and wellbeing.

We give a big thanks to Dr. B for taking the time to educate readers of The Mom Report! Follow Dr. B on Instagram or visit his website here.