The Ecology of Humans (2-1) Infant Exposure

Infant Exposure

Fetuses are first exposed to their mother’s microbiome through the placenta. These microbes provide nutrients, guide growth, and help keep the fetus healthy.

An infant’s body relies upon microbial signals to properly develop. Microbiota are in constant communication with human cells as well as other microbes.

Microbiota transfer from mother to child is important to future health prospects. Babies born naturally are coated with the microbes from their mother’s birth canal. But babies born by surgical Caesarean section are covered in microbes typically found on the adult skin. The difference can be telling. Babies delivered by C-section are more likely to have early health problems, particularly breathing and skin related. The risk is aggravated by early delivery.

Besides getting bathed in mom’s microbes during delivery, breast milk feeds commensal bacteria to infants. Bifidobacterium dominates the gut of healthy, breast-fed infants, and is important in a well-functioning immune system.

By contrast, the bacteria Staphylococcus aureus is more predominant in the digestive system of infants who become overweight children. Staph is famous for its resistance to antibiotics, and has been linked to chronic, low-grade inflammation, as well as being a factor in obesity.

Microbial exposure is important to immune development. ~ American pediatric immunologist Anthony Horner

The criticality of microbiotic transfer through breast milk is illustrated by the startling rise of autism in the United States from the late 20th century, as breastfeeding became less common. Recently, researchers have successfully ameliorated autism in young children through artificial microbiotic transfers.

Breast feeding is not just for baby. The microbiome must be fed.

Breast milk contains large amounts of oligosaccharides that the baby cannot metabolize, but the microbiota can. ~ English biologist Kevin Foster et al

Many animal moms deliberately transfer their microbiomes to their offspring. Infant elephants eat mom’s feces to acquire the microbes needed to digest food. Sand puppy pups plead for anal excretions from their parents, to get the healthy microbes they need. For many animals, motherly devotion involves slathering younglings with microbial cultures, giving new meaning to the tradition of passing culture down through the generations.