There is a persistent myth about infant gut development that comes up in nearly every online discussion of starting solid foods. It’s the myth that infants have a “virgin” or “open” gut until around 6 months of age. I’ve received so many emails, Facebook posts, and comments about the virgin gut over the last few years that I thought it was finally time to take a look at the science – and lack thereof – behind this myth.
I have written before, in my book and on my blog, about the controversy around when to begin introducing solid foods to a baby. Some health organizations recommend 6 months of exclusive breastfeeding, while others recommend starting to offer solids between 4 and 6 months, following baby’s cues of readiness as your ultimate guide. Based on my analysis of the most current science, I believe that the second approach is more evidence-based and helps parents to focus on their baby’s unique development rather than the calendar. I also think that it’s just fine to wait until 6 months if that is your preference.
However, whenever I discuss this science, someone lectures me about infant gut development, and they usually send me a link to KellyMom’s page on the topic, which urges parents not to offer solids before 6 months. Here’s what it says:
“In addition, from birth until somewhere between four and six months of age babies possess what is often referred to as an “open gut.” This means that the spaces between the cells of the small intestines will readily allow intact macromolecules, including whole proteins and pathogens, to pass directly into the bloodstream. This is great for your breastfed baby as it allows beneficial antibodies in breastmilk to pass more directly into baby’s bloodstream, but it also means that large proteins from other foods (which may predispose baby to allergies) and disease-causing pathogens can pass right through, too.”
Wow, that does sound scary! I can see how this “open gut” idea would worry parents approaching the transition to solid foods. But here’s the thing: There are no references given to support these statements, and in all my reading of the research literature on readiness for solids, I have not encountered science backing this concern. Yet somehow this idea of the open gut comes up over and over in online discussions, complete with judgment for parents who offer solids before 6 months and non-evidence-based suggestions about how to “heal” a baby’s gut. All of this only serves to increase anxiety in parents, which is the last thing any of us need.
It’s time to get to the bottom of this. Let’s look at some science…
What do we mean when we talk about an “open” or “closed” gut? How do we measure this? Read more