Building a Healthy Gut for Baby

Our intestines are a miraculous part of our living system. In our gastrointestinal tract, foods are broken into their component nutrients and are distributed throughout our body. But our digestive tract is also home to a complex array of microorganisms that either keep us healthy or make us sick. This part of our immune system has innate mechanisms to protect us from disease, as well as adaptive components that develop over time or from exposure. When the intestines are full of good bacteria, potentially harmful bacteria have a lower chance of causing illness.

Happy BabyThat being said, the first microbiota that colonize a human gut will pave the way for our future health. Researchers have long believed that babies are born with “virgin guts,” or, in other words, sterile gastrointestinal tracts. It was thought that the first microflora to colonize a baby’s system were those the newborn was exposed to via the mother’s skin and genitourinary tract during and immediately following birth. More recent research, however, seems to show that a baby begins to acquire his gut bacteria in utero from the mother’s digestive system. These bacteria are affected by the maternal diet and lifestyle, and have been linked to an increased risk of the child developing different types of disorders.

Once the baby is born, he is exposed to trillions of microbes that begin to show up in the mucosal lining of his gut. The types of microbes are dependent on a multitude of factors, including how he was born and how he is nourished following birth. Babies born vaginally have different gut bacteria compared to babies born by cesarean surgery. In one study, for instance, babies who were surgically delivered had a higher colonization with C. difficile – a microorganism that causes severe diarrhea and intestinal disease – than their vaginally born counterparts. The babies born vaginally had higher counts of bifidobacteria, a “friendly bacteria” that helps to maintain gut health. Other research has shown that babies born by cesarean are at an increased risk of developing allergies, asthma and other immune system–related troubles than are babies born vaginally, and the gut colonization may be the source of this morbidity.

Individual properties found in human milk provide protection for the baby’s developing immune system, but more importantly, these protective factors may work in concert to provide even greater protection than previously realized. One of the greatest effects of human milk is the “protective coating” it imparts within the newborn’s immature gut. Babies are born without tight junctures between the cells of the intestinal lining. Because of these gaps, pathogens are more likely to cause problems for the baby’s health. Colostrum and then mature breastmilk contain secretory IgA, an antibody that coats the intestines, providing a protective barrier until gut closure, which can take as long as several months.

Babies are born with passive immunity to environmental insults – they have the protection of maternal antibodies passed to them via the placenta before birth. Breastfeeding continues this process by providing a baby with active immunity. Active immunity is a cornerstone of health – when the immune system is exposed to a pathogen it creates a memory of the contact that can be recalled to produce an immune response in the future. When a breastfed baby encounters a pathogen, he can trigger the entero-mammary pathway where the mother’s body recognizes the challenge (through contact with the baby’s saliva), creates an antibody, and then delivers that antibody to the baby through the breastmilk. This relationship is absent for babies who are fed formula.

Indeed, the gut flora of a formula fed baby is very different from that of a breastfed baby. Breastfed babies tend to have more probiotics in their systems, keeping them healthier overall, while formula-fed babies are more likely to be colonized with pathogenic bacteria. Formula changes the acidity of the gut environment, potentially leading to the overgrowth of pathogens, while breastfeeding helps to create an acidic gut milieu unfavorable to growth of harmful bacteria. Even just one bottle of formula for a breastfed baby can disrupt the balance in the gut, and it can take several weeks to restore the integrity though breastfeeding.

With all of these factors impacting a developing baby’s immune system growth, parents may wonder what they can do to maximize their baby’s gut health. Consider these tips:

  • Eat a healthy diet in pregnancy. Choose a variety of natural foods, and limit highly refined or processed foods. Eat organic foods, when possible.
  • Avoid cesarean birth. Increase the chances of a vaginal birth by choosing your caregiver thoughtfully, hiring a doula to support you in birth, staying active during labor, using non-pharmacological methods of pain relief in labor, and using spontaneous pushing.
  • Advocate for and request immediate skin-to-skin contact with your baby, and keep mom and baby together throughout the hospital stay. Even better – consider home birth. Mom’s skin flora are better for baby than the unknown microorganisms found in a hospital room. Studies have shown that babies who are kept in contact with their mothers following birth are colonized with her microflora, while babies care for by the nursing staff are more likely to be colonized with harmful bacteria prevalent in hospitals, including c Difficile.
  • Breastfeed as soon as possible after birth, and supplement only if medically necessary.
  • Hold the solids, waiting for gut closure and infant readiness before starting to complement breastfeeding.
  • Avoid antibiotics unless medically necessary. Antibiotics unbalance the gut microflora. If the medications are necessary, consider using a probiotic in conjunction with the drug treatment to help maintain gut integrity.


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