Like many of us, you may think of yourself as a single organism (“me, myself, and I”). But evidence to the contrary is now clear: there is you, and then there are your microbes. We now know that roughly one hundred trillion microorganisms (mostly bacteria) live all over our bodies, including on our skin, in our mouths, nasal passages, and most importantly, in our guts.  The digestive tract is the most diverse and complex ecosystem that we have.  These organisms are collectively known as our microbiota, or microbiome. They make up one to three percent of our body mass, or roughly two to three pounds. There are ten microbial cells in our bodies for every one human cell. Their sheer number is astounding. While the science is still young, these microorganisms seem to have a profound effect on our lives.  From modulating our immune systems to regulating our metabolisms, to affecting our risk of chronic disease and even affecting our moods, our microbiome plays a significant role in overall health.

Birth and Infancy — The microbiome begins to take shape from the moment we are born.  Vaginal deliveries bathe babies in a sea of the mother’s microbiota, a key contributor to the development of a baby’s microbiome. C-section babies are deprived of these bacteria in the mother’s birth canal. (This is by no means to negate their clear necessity in many situations.) This is so concerning to some that research is now looking into sponging the birth canal of mothers who have not delivered vaginally and inoculating their babies with it. Similarly, breast milk contains many microbes that an infant needs to develop its own microbiome. Usually by age three, with weaning and the introduction of solid foods, a child’s microbiome looks similar to that of an adult’s. 

Immune System — The microbiome plays an important role in the immune system. It teaches the immune system who is friend and who is foe. It moderates the immune system as well, revving it up or down depending on the situation. Many believe that a lack of proper microbial education during the early years of life leads to an over-reactive immune system that may be at the root of the alarming rise in food allergies, asthma, and autoimmune disease we see today.

Chronic Disease — Mounting evidence is revealing a link between a person’s microbial ecosystem and their risk for chronic disease such as diabetes, certain cancers, Inflammatory Bowel Disease, cardiovascular disease, autoimmune disease, and neurological diseases such as Alzheimer’s and Parkinson’s. Why are these conditions on the rise? Some believe it is due to the diminishing diversity of our microbiome. When compared to more rural populations in less developed nations, the microbiota of those on a Westernized diet is less diverse and contains different microorganisms. While it is not yet clear which types of microbes are ideal, this difference between the microbiomes may be key when we think about how much more susceptible we are in the Western world to the chronic diseases mentioned above.

Metabolic Syndrome — Research suggests a link between the microbiome and weight, obesity, and insulin resistance.  Studies on mice reveal that, when given fecal transplants from leaner ones, overweight mice improve their insulin resistance. Gut microbiota can affect our appetites, causing us to crave and eat certain foods that uniquely benefit certain strains. Other bacteria change our metabolisms, allowing us to extract more or fewer calories from the foods that we consume. This may be why two people eating the same foods can gain or lose weight very differently. 

Mood — There seems to be a link between the microbiome and both mood and temperament. One experiment gave fermented beverages to depressed people for four weeks.  Many saw improvements in their mood, and MRIs showed changes in their brain activity. Other animal studies have seen changes in anxiety and extroversion after fecal transplants.

While it is not exactly clear how to create the ideal microbiome, there are some factors within our control that would likely favor a healthy one.

Fiber — Nurture your microbes by adding fermentable prebiotic fiber.  These fibers feed the microbes in your gut, which in turn produce healthy fatty acids that nurture the epithelial lining of your colon as well as produce many health-promoting compounds. Ideally, eat fiber in the form of real foods. All plant foods contain fiber, such as vegetables, fruits, and whole grains. Good choices include Jerusalem artichoke, jicama, chicory, dandelion greens, oats, barley, anything in the allium (onion) family, yams, bananas, cooked carrots, among many others. Make at least half your plate vegetables, and be sure to include starchy ones as well.

Fermented Foods — Include fermented foods in your diet.  Fermented foods naturally contain health-promoting living microorganisms that will, at least temporarily, inhabit your gut. Examples include sauerkraut, fermented vegetables, kimchi, yoghurt, kefir, and fermented beverages such as kombucha, beet kvass, and water/milk kefirs.

Processed Foods — Limit processed foods. Processed foods often contain white flours, sugar, and other sweeteners.  These foods are nutrient poor, but they can also feed the unfavorable bacteria in the gut. Keep these foods to a minimum, or if you can, completely avoid them.  

Lastly, engage with the outside world. This goes for adults as well. While hygienic habits like staying clean and washing one’s hands clearly have their place, we would benefit by not taking this to the extreme. Many believe that our germ-phobic lifestyles have negatively impacted our health.  So get outside and play.

The information provided in this article is intended for general use only and is not to be used in place of medical advice from a licensed health professional.