The Importance of a Virgin Gut: Breastfeeding Is More Essential Than We Thought

virgin gut

If you've heard the phrase, “virgin gut,” you may already know how important it is to the health of your baby. If you haven't, you're not alone. In essence, a virgin gut is a new term used to describe the clean slate gut of an infant who has yet to take in formula or solid foods and has only ever had breast milk as a form of nourishment.

Breastfeeding has come in and out of favor in the last several decades, but as research continues to shed light on just how essential breast milk is for health, society is thankfully moving back towards exclusive breastfeeding and delaying solid food until after six months.

Infant Feeding Through the Ages

Infant feeding practices have changed remarkably over the last century, and we’ve come a long way in our understanding of infant care and the importance of breastfeeding to long-term health.

Early 1900s: Mothers (or wet nurses) breastfed their babies exclusively for the first eight or nine months of life, providing all the nutrients needed for optimal health and a strong immune system.

1900-1920s: As doctors began recommending scheduled (as in, shortened and less frequent) feedings, many mothers struggled to make enough breast milk and cow milk became popular. Babies failed to thrive on animal milk, and experts encouraged the introduction of solid foods between two to four months of age to supplement.

1920s: Scientists began developing non-milk formula, and aggressive advertising led to a steady decline in breastfeeding rates all over the world.

1930s-1960s: Pureed fruit and vegetable baby foods became available in the 1930s and many parents introduced these early in order to get babies ready for finger foods at six months.

1970s-1990s: Although breastfeeding enjoyed a renaissance in the 1970s, by the 1990s the majority of babies were eating some form of solid foods by four months.

2002: The World Health Organization recommended exclusive breastfeeding for the first six months of life; several other organizations have since followed suit and breastfeeding rates are on the rise!

Indeed, new research is showing that maintaining a virgin gut by exclusively breastfeeding for the first six months is crucial not only for growth, but also for proper development of a baby’s delicate microbial system, the human microbiome.

The Power of the Microbiome

Home to around 100 trillion microorganisms, your microbiome hosts a combination of good and bad microbes that work together to exert a powerful influence on your wellness and vitality, including the state of your digestive system, your immune and endocrine systems, and even the health of your brain.

But, we aren’t born with a balanced microbiome teeming with good bacteria. In fact, before birth, infants have nearly sterile guts—it’s not until babies begin to leave the womb that they start to acquire the bacteria that will make up the microbial mix that is their foundation of health.

With 80% of the immune system residing in the gut, it comes as no surprise that a healthy balance of microbes plays a pivotal role in the strength of a baby’s immune system, not just in infancy but for many years to come.

Breast is Best for a Balanced Microbiome

An infant’s first kickstart of microbe inoculation begins as they prepare to enter the world, gathering bacteria as they pass through the birth canal. Directly after birth, they continue to acquire bacteria from skin-to-skin contact, the environment, and—perhaps most importantly—from their mom’s breast milk.

Breast milk is truly a miracle food, dynamic, individualized and packed with vitamins, minerals, probiotics, antibodies, growth factors, and tons of unique sugars full of prebiotics that selectively feed your baby’s good bacteria. You see, babies can’t digest these sugars—their sole purpose is to feed the beneficial bacteria in the gut, particularly Bifidobacteria. A healthy population of flora helps babies absorb nutrients, produces vitamins and antibacterials, and stimulates the immune system.

Here’s where it gets interesting. For the first four to six months of life, infants have “open” guts, meaning that there are actual spaces between the cells in their small intestine that allow large molecules to pass into their bloodstream and influence their overall health and development. Just what passes through depends entirely on what the baby eats.

Not only does breast milk provide the perfect ingredients for beneficial bacteria to multiply, but it seems to affect how they grow as well. Researchers at Duke University Medical Center tested bacterial growth in breast milk, cow’s milk, and infant formula and found that in breast milk the bacteria grew together into layers that protected the gut and sealed the openings1.

This could help explain why studies also show that the open gut closes more quickly in babies who breastfeed exclusively2 and why breastfed infants are notoriously healthier, both during infancy and as they grow.

If you are exclusively feeding your baby this “liquid gold” during the first six months of life, the only things passing through the open spaces and into the bloodstream are beneficial antibodies and other compounds designed and evolved specifically to sustain life and set up your baby’s immune system for lifelong health.

A baby who is exclusively breastfed is receiving the perfect balance of nutrients to support growth and development of both the baby and the baby’s microbiome. Solely providing breast milk to maintain your baby’s virgin gut for the first six months of life protects the gut environment so that it can develop and mature as nature intended, thereby laying the foundation for optimal health.

Giving Formula and Solid Food Too Soon

But what happens when you introduce formula or solid foods before the gut has a chance to close and mature? Well, the proteins in formula and solid food—that your baby isn’t ready for—slip through the cracks and enter the bloodstream, possibly resulting in an overstimulated immune system.

Furthermore, without those valuable prebiotic sugars (found only in breast milk), the microbes that your baby does have no longer thrive and different, less beneficial, bacteria begin to set up shop in their gut.

In other words, the moment you introduce even one bottle of formula or one scoop of rice cereal into your baby’s open gut (even if you are also breastfeeding), you could be altering your baby’s microbiome for the worse. In one recent study, researchers found that infants who consumed both breast milk and formula had microbiome compositions that were similar to exclusively formula-fed infants3.

Maintaining a Virgin Gut

The best thing you can do to maintain your baby’s virgin gut is exclusively breastfeed for the first six months. Just remember to stay vigilant, as this is often not as easy as it sounds! Well-meaning nurses, friends, and even family members may still be operating under the old paradigm of thought and may be quick to suggest supplementing with formula soon after birth in an effort to help you adjust to being a new mom (and in your sleep-deprived state, you may be tempted to agree).

However, formula given during the first week of life can delay the development of healthy gut flora by two to six weeks—a critical time of development—so sticking to your breastfeeding plans comes with a big payoff for your baby4.

Luckily the tides are changing, and scientists, doctors, and mothers alike are realizing that there’s just no substitute for breast milk. The American College of Obstetricians and Gynecologists (ACOG), the World Health Organization (WHO), the American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) all now recommend six months of exclusive breastfeeding for infants.

Maintaining a virgin gut until your baby’s half birthday will ensure proper microbial and immune system development and is one of the best gifts you can give to your child for lifelong health and wellness.

Remember: Healthy Mom, Healthy Baby

While you’re doing everything you can to make sure your baby gets the best possible start by breastfeeding, you need to make sure that you are taking care of your microbiome as well. Now that we understand how bacteria transfers from mom to baby and why it is so important, we know how vital it is to ensure that your gut environment is teeming with good bacteria to pass on to your baby.

While you’re breastfeeding—and preferably starting prenatally—you can supplement with a high-quality, tailored probiotic like Hyperbiotics PRO-Moms to make sure you have an abundance of beneficial bacteria to pass on to your little one, encouraging an optimal start at a healthy life.


1. Zhang, A. Q., Lee, S. Y., Truneh, M., Everett, M. L., & Parker, W. (2012). Human Whey Promotes Sessile Bacterial Growth, Whereas Alternative Sources of Infant Nutrition Promote Planktonic Growth. Current Nutrition & Food Science CNF, 8(3), 168-176.
2. Catassi, C., Bonucci, A., Coppa, G. V., Carlucci, A., & Giorgi, P. L. (1995). Intestinal Permeability. Changes during the First Month. Journal of Pediatric Gastroenterology and Nutrition, 21(4), 383-386.
3. Madan, J. C., Hoen, A. G., Lundgren, S. N., Farzan, S. F., Cottingham, K. L., Morrison, H. G., . . . Karagas, M. R. (2016). Association of Cesarean Delivery and Formula Supplementation With the Intestinal Microbiome of 6-Week-Old Infants. JAMA Pediatrics, 170(3), 212.
4. Walker, Marsha. (2013). Breastfeeding Management for the Clinician: Using the Evidence. Burlington, MA: Jones & Bartlett Learning.


Julie Hays is the Communications Director here at Hyperbiotics. Health writer and mama of two little girls, Julie's on a mission to empower others to live lives free of the microbial depletion many of us face today. For more ideas on how you can maximize wellness and benefit from the power of probiotics, be sure to subscribe to our newsletter.

Posted in Mom + Child, Pregnancy & Breastfeeding