What is the Virgin Gut?
Until around six months of age babies have what is often referred to as an “open gut”. This means the spaces between the cells of the small intestine will allow large molecules to pass directly into their bloodstream. Consequently, as well as the beneficial antibodies in breastmilk passing into baby's bloodstream, allergy-triggering proteins from other foods, disease-causing pathogens and other nasties can also pass through.
If breastmilk is all that has ever entered baby’s gut, it is often referred to as a “virgin gut”. Antibodies and other constituents of breastmilk create this unique environment (Wade 2010; Current Nutrition & Food Science 2012; Molecular & Cellular Proteomics 2012). For instance, some of the sugars found in breastmilk promote the development of a substance called Lactobacillus bifidus, which makes the gut more acidic, thus helping to stop harmful bacteria from growing. Another substance found in breastmilk - Lactoferrin - binds with iron in your baby, thus starving harmful bacteria of the iron they need to multiply.
Furthermore, recent research has linked a component of breast milk called oligosaccharides (HMO for short) to the maintenance of the perfect virgin gut. Here's how it works: the human body does not possess the enzymes to break down HMO, so it passes through intact to the large intestines. HMO then produces short-chain fatty acids which beneficial bacteria feed on, thus maintaining a healthy population of microbial in the infant's intestines. But wait! It gets even more interesting, "As the baby grows older and its digestive patterns change, the breast milk automatically regulates the bacterial levels to maintain a healthy balance that suits the baby's evolving needs" (Khalfan Al Ghazal 2012). These beneficial bacteria strengthen the immune system so that in the long term it can fend off chronic health problems like food allergies and asthma (Donovan 2012; Chapkin 2012).
If you’re a combined feeder look away now.
Here comes the killer fact. Only small amounts of formula or solid foods cause a shift that destroys this environment, changing acidity and destroying the immunoglobulins that coat mucosal surfaces. “Just one formula supplement per 24 hours will result in an almost immediate shift from breastfed to formula-fed gut flora - in which good bacteria (Bifidobacteria) are no longer dominant” (Mackie, Sghir, Gaskins. Bullen, Tearle, Stewart). This means that your baby is more likely to develop allergies later on as your baby's gut becomes 'sensitized' (Lim 2009). The process has been described as follows:
That foreign proteins damage a young baby's immature gut was noted by the BBC in 2007 in an article about HIV transmission. Babies of mothers in developing countries who did not exclusively breastfeed were almost 11 times more likely to acquire the infection. "This higher risk is due to the larger, more complex proteins which may lead to greater damage to the lining of the stomach, allowing the virus to pass through the gut wall" (BBC).
More recently, researchers from Duke University grew bacteria in samples of infant formulas, cow's milk and breast milk. The infant formulas and the cow's milk were incubated with two strains of E. coli bacteria – helpful cousins to the dangerous organisms associated with food poisoning. Within minutes, the bacteria began multiplying in all of the specimens, but there was an immediate difference in the way the bacteria grew. In the breast milk, bacteria stuck together to form biofilms - thin, adherent layers of bacteria that serve as a shield against pathogens and infections. Bacteria in the infant formula and cow's milk proliferated wildly, but it grew as individual organisms that did not aggregate to form a protective barrier (Current Nutrition & Food Science 2012).
Even more shockingly, recent research has revealed that formula actually causes cell death, whereas breast milk does not. In the study, cells that line the intestine and blood vessels, along with white blood cells that control inflammation caused by trauma, were virtually eliminated during the process of digesting formula (you can read the study here).
How to recover your baby's gut
However, before you reach for the hangman’s noose, all is not lost. "Virgin" gut seems to suggest that once a baby’s gut has lost its virginity it can never get it back. This is misleading as such acute sensitivity only applies to the first seven days of life. Providing you gave your baby formula after this time, “if breastmilk is given exclusively again, thereafter it would take 2-4 weeks for the intestinal environment to return again to a state favouring Grampositive Flora” (Brown & Bosworth; Gerstley, Howell, Nagel). In other words, you can repair your baby’s gut if, like me, you ignorantly administered a formula top-up or two. Several weeks of exclusive breastfeeding should restore the “damage”. This means no water, formula or other complimentary foods. The Department of Health, Word Health Organisation and Unicef recommend maintaining the virgin gut for six months, after which solids can be introduced.
So let’s assume you’re a bona fide Alpha Parent and have maintained your baby’s virgin gut. Firstly, hark at you! I salute you. Secondly, be smug. It’s no mean feat exclusively breastfeeding when everyone around you (in-laws, friends, health visitors) are pressuring you with formula top-ups, juice and boiled water, as well as cracking open the
What about Calpol?
Or infacol or gripe water?
Some commentators argue that Calpol is of equal danger to formula measure for measure. However as baby isn’t given 200ml of Calpol at a time (I hope!) then formula is much more detrimental to the virgin gut than the odd 2.5ml/5ml of Calpol.
Other commentators maintain that only items containing foreign proteins or enzymes will damage the virgin gut. This is because only they penetrate the gaps between the cells of the wall of the intestines. Calpol, Infacol and the like are designed so they pass through the system unabsorbed (unlike milk protein) so technically they don't count.
Either way, the general consensus is that Calpol and other medicines do not ruin a baby’s virgin gut. The Word Health Organisation's definition of exclusive breastfeeding allows for vitamins, minerals and medicine.
However, Calpol has other problems. As a product, it contains E numbers which can trigger eczema in sensitive children. In fact, some forms of Calpol have been banned in the UK. An alternative to Calpol is soluble Disprol which is essentially pure paracetamol sans the pink additives.
What about bacteria, particles of soap, etc?
When I originally discovered the virgin gut theory my first thought was “I fail at life”. My second thought was “this is tripe”. Babies are constantly sucking on (not very clean) things and ingesting random items. I wondered whether the virgin gut research used a definition that meant “never had formula” or was it “never had anything but breastmilk”. Because if was the latter then it would be virtually impossible to guarantee and control between babies across any study. As a Mumsnet user elegantly put it, “I think my son's downfall was the day I caught him licking the dog.”
The answer to this conundrum is a fascinating one. Breastmilk flushes out viruses, bacteria, particles of dirt, and other small microbes while at the same time lining the gut to protect it against allergens and infections until it closes up at around 6 months. Anything other than breastmilk (food, formula, water, Calpol) will affect the virgin gut but the breastmilk will then re-coat the gut afterwards. This re-coating process may take a few days or weeks depending on the quantity of foreign product given. However the process is not without its limitations. If formula is given within the first week of a baby’s life, the gut may be too immature to repair itself, and virgin gut status may never be maintained.
So ultimately, how important is the virgin gut?
The idea of virginity, aka a clean slate, appeals to the Alpha Parent in us. It provokes perfectionist tendencies. Hands up if you have ever been on a diet and refused a crisp because it would ruin your fat-free clean slate. Even though one crisp would not damage your diet, there is a compelling drive to be flawless.
If a baby is born into a family with a history of allergies, their parents may want to pay particular heed to the virgin gut theory. Research suggests a link between the virgin gut and a lower incidence of allergies and food sensitivities. The theory is that the porous nature of the immature gut allows irritants to go straight through and cause a life-long over-reaction whenever that substance is encountered. Thus, just one bottle of formula can sensitize babies who may be allergic to cow's milk protein or soy protein. However, for the vast majority of babies, the idea of virginity is far less important than a baby's general health and comfort.
Always remember that failing to maintain the perfect virgin gut does not negate the bulk of breastfeeding benefits. Any amount of breastmilk, aka liquid gold, is significantly better than none.
For further information on the virgin gut, I urge you to read this article: “Just One Bottle Won’t Hurt” - or Will It?