The World Within Us

There is a vast network of microbes that call your body home. We acquire these microbes throughout our lifetime by breathing,  touching,  and eating. Such bacteria were the only inhabitants of earth for three billion years. Their chemical reactions supported the conditions that allowed for the development of multicellular organisms and, eventually, superorganisms like us. We evolved together, symbiotically supporting each other.

100 trillion microbes of 10,000 species reside in and on us. On our skin, in our intestines and on our teeth. This flora, the aggregate of  bacteria and other microorganisms, is responsible for multiple functions including proper absorption of nutrients, reduction of harmful substances and discouragement of “bad” bacteria as well as yeast and fungus. These helpful bacteria influence our immune system not only by creating specific antigens to fight the microbes that can harm us but also, likecops, direct the immune system to identify who the “bad” guys are and how to fight them.

We are made up of interconnected human and microbial parts that depend on each other for survival. This relationship is commensal as we benefit each other. We trade room, board and three squares a day for help with cleaning up, converting nutrients and keeping the place safe from unwanted invaders. In cell to cell ratio and in genes they have us beat. These marvelous microbes outnumber our own cells 10 to 1. Genetically we are outnumbered 360 to 1. Even more astounding is that our flora is as unique to us as our own fingerprints. Even identical twins, raised in the same environment will have different microbial genome types.

These fantastic flora do many essential jobs in the body, but only recently have scientists begun to see just how much they are actually responsible for. Studies with germ-free mice (mice raised in a sterile environment with no exposure to bacteria) have shown that the gut microbes may also play a role human behavior and emotions. The effects of stress on germ-free mice show that they are far less able to cope with stressful circumstances than their immunity-acquired counterparts. Additionally, those mice with minimized microbiomes are unable to solve problems the way their microbe-rich cousins can.   In other words, our gut microbes can influence how we think, act and feel. And, considering how many more bacteria there are in our body than our own cells, it’s no surprise than they can have such a profound affect on our well-being.

This phenomenon is due, in part, to the fact that the majority of our “happy” hormones, dopamine and serotonin, are synthesized in the gut with help from our microbe friends. These hormones help to regulate our emotions,  which impact our decision making. In a study in California,  two groups of women were presented with stressful imagery  via virtual reality and asked to perform tasks to solve the issues they were presented with. Those women with more diverse microbiomes showed a more active hippocampus. The hippocampus, thought to be the emotional center of the brain as well as the holder of both short and long term memory, is located under the cerebral cortex in the brain.  Those women with more microbes were able to problem solve more effectively and showed less stress markers (high blood pressure and increased heart rate) than those women who had less diversity in their gut flora. The diversity and density of the flora in the gut has a direct relationship with the activity of the hippocampus. In other words- the gut brain connection.

Our diets, as well as our choices of medications, cleaning products and beauty products have a dramatic impact on the health of our microbiome. The scorched earth policy that we have had when it comes to killing so-called “germs” has been that they are all bad and should be killed. Anti-bacterial soaps, body washes, and antibiotics that diminish our friendly microbes are having negative long-term affects on our health and mood. I am not saying that antibiotics or antibacterial sprays should never be used. Rather, they should be used more selectively and less universally to help preserve and protect the microbes that help us. When we do require an anti-microbial it is important that those microbes get replenished through probiotics and probiotic rich foods like sauerkraut and komucha so that the microbes can recolonize and continue doing their job. This will make us all happier and healthier.

By Tapp Francke