Mothers make thousands of critical choices the moment they find out they’re pregnant, and once their baby is born, one of the first and most importance decisions they’ll make is how to feed their newborn. Breastfeeding researchers from the Henry Ford Hospital have discovered why some babies’ immune systems become susceptible to developing allergies and asthma while others grow up without worrying about a sniffle. The findings reinforce the ongoing medical theory that breastfeeding has the ability to protect the baby in ways hand sanitizer never could. Researchers presented their study at the American Academy of Allergy, Asthma & Immunology annual meeting in Houston.

"For years now, we've always thought that a sterile environment was not good for babies," said the study’s lead author Dr. Christine Cole Johnson, chair of Henry Ford's Department of Public Health Sciences, in a press release. “Our research shows why. Exposure to these microorganisms, or bacteria, in the first few months after birth actually help stimulate the immune system. The immune system is designed to be exposed to bacteria on a grand scale. If you minimize those exposures, the immune system won't develop optimally."

Researchers conducted six separate studies that evaluated whether breastfeeding had any effect on a baby’s gut microbiome and if they wound up with any allergies or asthma. Breastfeeding exposes a baby to his mother’s personal collection of microorganisms in the gastrointestinal (GI) tract, which eventually reflects itself in a baby’s diaper. Researchers analyzed stool samples from infants between one and six months after they were born, and tracked how their T-cells developed — these white blood cells are essential for immune system development. They work by circulating throughout the human body, scanning for abnormalities and infections that may threaten a person’s health.

When they examined 1-month-old breastfed babies, they found a distinct microbiome within their gut that put them at a lower risk for developing pet allergies. The research team at Henry Ford Hospital are building on a strong foundation of discoveries, but they also had to take other factors into consideration. They found a baby’s gut microbiome pattern varied depending on the mother’s race, how long the pregnancy lasted, pre- and post-pregnancy exposure to tobacco smoke, caesarean versus vaginal birth, and if the baby’s parents were pet owners when the baby was brought home. In 2002, they discovered a baby’s exposure to cats or dogs within their first year of life reduced their risk of developing allergies.

"The research is telling us that exposure to a higher and more diverse burden of environmental bacteria and specific patterns of gut bacteria appear to boost the immune system's protection against allergies and asthma," Johnson said.

A mother’s combination of cells, hormones, and antibodies fed to the baby through her breastmilk provides unique protection for the baby, according to the Office on Women’s Health, a division of the Department of Health and Human Services. Not only does it play a role in allergy development, but it also influences a baby’s risk for childhood leukemia, obesity, type 2 diabetes, ear infections, eczema, diarrhea and vomiting, lower respirator infections, and sudden infant death syndrome (SIDS).

Research has shown the benefits of breastfeeding have outweighed the consequences for decades. Mothers whose schedules are too busy to attend to their babies' nutritional development miss out on benefits synthetic formula could never fully mimic. In fact, the Office on Women’s Health also found that if 90 percent of families breastfed exclusively for six months, 1,000 infant deaths would be prevented.

Not only that, but the bond a mother makes with her child provides the baby with an irreplaceable feeling of safety and comfort that arises from a mother’s familiar, innate scent, which comes from pheromones. In a mother's arms, a baby’s cells will become programmed to flourish in that particular environment — reinforcing protection, safety, survival, and optimal development.

Source: Johnson CC, et al. At The American Academy of Allergy, Asthma & Immunology Annual Meeting. 2015.