5 Interesting Facts About the Human Microbiome

January 21, 2016

The human microbiome is fascinating! There has been a HUGE paradigm switch over the past couple of years, as we are beginning to realize just how important our diverse colonies of microbes are for our body. We went from fearing ALL bacteria, to realizing how much we need it to thrive and survive.


Here are 5 interesting facts you may not have known about our collective “bugs” or bacteria known as the microbiome!

Our body holds more than 100 trillion bacteria all over our skin, all over our body, in our mouths, ears, nose, armpits, and throughout our intestines. They live in diverse bacterial communities collectively known as (or the new trendy term) “The Human Microbiome.”

What exactly does the microbiome do for us? These tiny buggars communicate with each other, and can synthesize vitamins and minerals, act as a “soldier” or “gatekeeper” in our gut to help keep pathogens out, boost our immune system, help us to digest our food, helps with our mood (some important brain chemicals like serotonin are actually synthesized mainly in the gut), helps prevent GI disorders like IBS and Crohn’s Disease…and science is constantly finding more roles these beneficial bacteria play. The health of the microbiome has been linked to obesity, type 2 diabetes, and even heart disease. Our bugs are pretty important, and we need to take care of them!

Here are 5 Facts you might not have known about the amazing microbiome:

1.  Our microbiome can weighs as much as an organ…approximately 3 pounds but can weigh up to as much as 5 pounds…5 pounds of microscopic bacteria that are working together in large communities to take care of YOU!


2.  Our microbes need to eat to survive too! This is where the concept of “prebiotics” comes into play. We take probiotics to replace beneficial bacteria, we take prebiotics to essentially feed that bacteria so it can survive, thrive, and colonize. Prebiotics are found in fiber rich foods-such as plantains and bananas, as well as asparagus, garlic, and onions. Prebiotic fiber is not digested, but rather works symbiotically with probiotics to increase the population of good bacteria. One form of prebiotics are resistant starches. Resistant starches are starches that we do not digest, but rather are utilized in the GI tract to feed bacteria, and have been shown to have many other health benefits. Resistant starch forms in foods after cooking and cooling. One example is using potatoes-cooking and cooling them forms resistant starch.


3.  The way your baby enters the world has a permanent affect on their microbiome! Scientists are finding that pregnant women pass significant microbes onto their infant while the infant passes through the birthing canal.  One study examined the changes in vaginal microbiome during pregnancy.  As early as the first trimester, the diversity of vaginal bacteria changes immensely. Species that were once quite abundant dissipate, and new species of bacteria arrive. One species that forms in the vagina, Lactobacillus johnsonii is usually found only in the gut, where it produces enzymes that digest milk. Changing conditions in the vagina during pregnancy encourage this strain of bacteria to grow.  During delivery, the baby will be covered by Lactobacillus johnsonii and even ingest some of it. This prepares the infant to be able to digest breastmilk. When passing through the birthing canal the baby swallows and is bathed in bacteria and even some feces. Babies are born down by the anus for a reason! There are colonies of beneficial bacteria down there. Babies born via cesarian are more likely to struggle with health problems like asthma, allergies, eczema, type 1 diabetes and celiac disease.

Some cesarian sections are necessary. What can a parent do to ensure baby gets bathed with this beneficial bacteria? One way to pass beneficial bacteria on to a cesarian delivered baby is via vaginal seeding, a way to bath the baby with bacteria from the vagina upon delivery. Skin to skin contact with a parent vs being swaddled continues to pass bacteria to baby. Breastfeeding is also extremely important to continue to inoculate baby with beneficial bacteria.


4.  Let your kiddos get their hands dirty and even taste a little! We are obsessed with hand washing, sanitizing, and cleanliness in our culture. This is not necessarily always a good thing. There are beneficial bacteria in soil. Babies put everything in their mouth for a reason, more than just exploration. Many cultures actually eat dirt and they perceive eating dirt as a normal thing. It helps strengthen the immune system and build up our resistance to pathogenic bacteria.

In fact, our cultural fear of dirt is having a negative impact on our microbiome!  According to Chris Kresser, author of Your Personal Paleo Code:

“Our culture’s obsessive attention to cleanliness, sanitation, and hygiene may actually be having unintended consequences on our immune system. While a sanitary environment may be crucial in areas such as hospitals or food production, our general avoidance of dirt, bacteria, and other infectious agents may be causing our under-stimulated immune system to become over-reactive to benign antigens.”

“Eating dirt” is associated with protection from chemicals, parasites, bad bacteria and toxins. So don’t fear dirt so much! Go ahead and let your kids dig, play, and get dirty.


5. Obese individuals tend to have a makeup of bacteria in their intestine that is different from that of people who are of normal weight. Recent evidence suggests that there is a link between metabolic diseases such as obesity and Type 2 diabetes and the bacterial populations in the gut. The proportion of two major groups of bacteria in the large intestine, Bacteroidetes and Firmicutes may play a large role. In this study comparing the distal gut microbiota of obese mice and their lean couterparts the researchers found that the obese microbiome has an increased capacity to harvest energy from the diet. Obesity was associated with changes in the abundance of bacteroidetes and firmicutes. They also found that the trait was transmissible:

“colonization of germ-free mice with an ‘obese microbiota’ results in a significantly greater increase in total body fat than colonization with a ‘lean microbiota’. These results identify the gut microbiota as an additional contributing factor to the pathophysiology of obesity.”

The human gut microbiota is an extremely complex and important system that affects human health. Up until recent times we have disregarded it’s existence and treated all bacteria as pathogenic. This has had a profound affect on our health, and the health of our offspring. We need to “water the flowers” and take care of our microbiome, so these trillions of bugs can in turn take care of us!

*Up next week: Ways you can nurture your microbes!


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