You’re not alone. In fact, right at this moment, your body is housing trillions of bacteria and other organisms that live on your skin, in your mouth, and even inside your digestive tract. But it’s hardly a cause for concern. In fact, your microbiome — the scientific term that researchers use to collectively refer to all the fungi, bacteria and viruses that live on and in your body — serves a very important purpose. Let’s take a peek inside your body and explore what your microbiome is, where it comes from, and what it does.

By the Numbers: How Many Bacteria, Fungi and Viruses Live in Your Body?

microbiomeIt’s long been said that each human body has 10 times the number of bacteria than it does actual human cells. However, this estimate is based on outdated data, although you’ll still hear this number thrown around in health-and-wellness pop culture.

That doesn’t mean the number of bacteria in your body isn’t impressive though. In a research report published in the peer-reviewed journal Nature, scientists came up with a more accurate (yet still massive) number.

“It’s often said that the bacteria and other microbes in our body outnumber our own cells by about ten to one,” points out the report. “That’s a myth that should be forgotten, say researchers in Israel and Canada. The ratio between resident microbes and human cells is more likely to be one-to-one, they calculate.”

That means the average 30-year-old person who weighs 70 kilograms and is 1.7 meters tall likely contains an average of 30 trillion human cells. Meanwhile the number of bacteria clock in at a jaw-dropping 39 trillion.

Where did all these bacteria come from? How did our bodies become such teeming beds of fungi and viruses? And should you be concerned?

The Evolution of Your Microbiome: Where Do the Bacteria Come From?

microbiomeIt all starts at birth, explains naturopathic doctor Gillian Flower, ND, in her column for Alive magazine. “The human microbiome is a vast community of more than 10,000 distinct species of bacteria, harmoniously colonizing our skin and mucous membranes,” she says. “In years past, childbirth was seen as the great initiator, colonizing the otherwise sterile environment of a baby’s gut. Bacterial fragments detected in both the placenta and amniotic fluid now suggest that this transfer begins during pregnancy.”

Bacteria begin to transfer from the woman to her baby before the baby is even born. This process then accelerates during the actual birthing process, where the infant is exposed to a barrage of bacteria in the birth canal. For example, studies have found that a child born via cesarean has a very different level of bacteria than a child born vaginally.

Even more bacteria get passed on to the baby during breastfeeding, and this process of bacterial, fungal and viral growth continues through childhood and even in adulthood.

The Purpose of Your 39 Trillion Bacteria

You may be worried to hear this news that your body is teeming with unseen guests. But for the most part, these bacteria serve very important purposes.

1. Bacteria Help You Digest Food

From day one, those bacteria get to work to help you digest food. For instance, the Bifidobacteria strain of bacteria in an infant’s intestines helps the baby to digest the sugars found in breast milk. Those same bacteria help you as an adult to digest and break down sugars, while other bacteria help you to metabolize fiber, protein and fat.

There are interesting side effects of all of this. For instance, since the bacteria help you to metabolize fats, studies have found that a healthy microbiome may help improve your cholesterol numbers and reduce your risks of heart disease. Other studies have noted a link between an unhealthy microbiome population and a higher risk of diabetes.

2. Bacteria Play a Role in Your Immune System

It’s not all about white blood cells and T-cells. Researchers have found that some bacteria assist with your immunity. Scientists say that the bacteria play a role in how the cells in your immune system communicate with each other, thus directly helping to speed up how quickly your immune system responds to an infection or injury.

3. Bacteria Help With Cognition and Mental Health

microbiomeSimilar to how bacteria improve cell communication within your immune system, bacteria also help your central nervous system to communicate efficiently. Thus, they may affect your brain, your behavior, and your mental health. Studies suggest that a healthy balance of bacteria in your body may:

  • Reduce the risks of depression, anxiety and other mental health concerns
  • Improve your resilience to stress
  • Improve your cognition, memory and focus
  • Lower your risks of cognitive disorders and diseases, including dementia

Of course, the exact mechanisms aren’t always understood. For instance, doctors have noted that patients with Alzheimer’s disease tend to have very different micriobiomes compared to patients without the disease. Does one cause the other? More research continues to be done to investigate this further.

In conclusion, the trillions of unseen residents in and on your body are a gift from mother nature. We provide these unseen residents with a place to live, and they in turn help our bodies to operate optimally. In the next few weeks, we’ll dive into how you can support this microbiome and ensure all the bacteria in your body are thriving.

The Microbiome Isn’t the Only Unusual Aspect of Your Body and Your Health:

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