cesarean sectionResearchers have recently reported a possible connection between method of delivery and allergies, including food allergies. The study, completed by researchers from Scotland and Sweden, was published in the journal Gut

The small study followed 24 children from birth to age two. Fifteen of the children were born vaginally and the remaining nine were born by C-section. Tests showed impaired diversity of gut bacteria in children born vaginally compared to those born by C-section. Of particular concern were the Bacteroidetes, associated with allergy protection. Researchers also noted children born via C-section are at increased risk of irritable bowel syndrome (IBS) and diabetes, as well. 

At the heart of the difference is contact with bacteria. When an infant moves through the birth canal they come in contact with bacteria found in the birth canal. These bacteria find their way into the body and spark the development of diverse gut bacteria. C-section deliveries are different in that infants never come in contact with bacteria found in the birth canal. 

In an attempt to counteract the intestinal impact of a C-section delivery, studies are planned that involve collecting bacteria from the birth canal and smearing the bacteria on the face of the newborn immediately after birth. The smear could mimic contact with the birth canal and thus spark diversity in gut bacterial development. 

Researchers also found high levels of Th1 cells in infants born vaginally. Th1 cells are known as chief cells. Chief cells can mute allergic response, something that is clearly missing in children with allergies. Infant born via C-section have lower levels of Th1 cells thus immune response to allergens is stronger. 

When infants are born the gut is sterile. It is only through contact with bacteria during delivery that initial species of gut bacteria start to grow in the intestines. Contact with the outside world, including a variety of foods, improves gut bacteria diversity which could mean infants born via C-section may require contact with solid foods earlier than infants born vaginally. “It might not be so good to have six months of only breastfeeding. Earlier exposure to ordinary solid foods may stimulate a higher diversity of the gut microbiota,” claims Maria Jenmalm of Linkoping University. 

Source: Jakobsson HE, Abrahamsson TR, Jenmalm MC, Harris K, Quince C, Jernberg C, Björkstén B, Engstrand L, Andersson AF. Decreased gut microbiota diversity, delayed Bacteroidetes colonisation and reduced Th1 responses in infants delivered by Caesarean section. Gut. 2013 Aug 7. doi: 10.1136/gutjnl-2012-303249.