Our bacterial heritage: one of mom’s best gifts

Today’s journey begins with a rather amusing encounter: an ever-wiggling spermatozoid with a self-composed egg. What happens next is a succession of events dictated by our memory blockbusters (our genes) until the birth signal is given. Pregnancy is indeed an exciting adventure filled with daily discoveries for the parents-to-be. During gestation, in order to allow the fetus to grow in a safe and nurturing environment, future mothers commit to a healthy lifestyle. Yet, have you given thoughts to another less conventional subject that may have a profound influence on the health of the beloved newbie? If your answer involves microbes, then you seem to be already open to a frank discussion around the inspiring world of human microbiomes.

Put simply, a microbiome is a miniscule (or tiny) ecosystem composed mostly of two microbial teams: a friendly team and another less amicable one. The beauty of this match lies in the fact that both teams should be present in decent proportions in order to keep the game going in a healthy manner. In today’s chapter, the spotlight goes to the vaginal and breast milk microbiomes. Why? Because both of them are major actors in giving babies a head start in life. Additionally, more broadly speaking, they are crucial for the vigorous survival of humanity.

By now, the idea that we only transmit our genomic dataset to our descendants is long gone. As a matter of fact, a master responsibility given to women consists in passing on her microbial collection, too. The most efficient way known today to allow this transfer to take place straightforwardly is by natural birth. The bacterial inhabitants of the birth canal will seed the skin, nostrils, face and ears and will get eventually swallowed by the baby, thus colonizing his/her intestines. In order to allow the bacterial newcomers to thrive in such an environment, breast milk comes next. More than one thousand structures of sugars, along with antibodies, proteins and at least 200 personalized bacterial species make up this precious white liquid. As you can imagine, this extraordinary complexity cannot be reproduced in marketed formulas today, and therefore breast milk is the most complete food for a baby’s development. In the first three years of life, changes in the types of food that toddlers ingest along with their constant contact with microbes allow an astonishing gut microbial development to happen. This special period has a direct implication in shaping the child’s immune system. However, health disturbances from today’s modern society, such as the overuse of antibiotics or obsessive avoidance of all germs, may lead to long-lasting negative health consequences since not only bad but also good germs are wiped out altogether. C-section is another delicate issue that raises concerns. Unless medically prescribed for life-threatening reasons, this practice should not prevail. Babies born by C-section get colonized mostly by bacteria present in the air and the caregiver’s and mom’s skin. In such circumstances, the birth canal microbes will not be seeded, and therefore will be dearly missed. Research today puts babies delivered by C-section in a group of having higher chances to develop allergies, obesity and type 1 diabetes later in life.

As odd as it sounds, thank your mom for the microbes you inherited. They are a long-lasting gift and the result of unconditional love and labor. After reading this article, pass it on to people in your circle. Everyone can revel in the beauty of human microbiomes. Humanity thanks you!

For more engaging microbiome stories backed by science:

http://www.womenandtheirmicrobes.com, Twitter (@WomenMicrobes) and Facebook page (womenandtheirmicrobes).

And for the science lovers: Younes et al., Women and Their Microbes: The Unexpected Friendship, Trends in Microbiology, (26) 1:16-32, 2018.


Digital art

Text by Fernanda Haffner

Illustration by Laurene Gattuso