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What Is My Microbiome and Why Should I Care?

Updated: Dec 6, 2021

Research on the gut microbiome has exploded in the past decade and it's time for everyone to bow to the royal microbes living in their digestive tract.

If you are a person who spends time on the internet, watches TV, or glances at magazine covers while standing in line at the grocery store, then you have likely heard the word “microbiome.” It sounds like it could be a small greenhouse…and it kind of is because it is made up of living things inside of our body. But what you may not know is how incredibly important this mini microbial universe is to your overall health!

The Microbiome is King

The microbiome has become the king of the body, and scientists are chomping at the bit to learn more about how this king rules the body and overall health. In the last decade, the research has exploded with more than 87,000 studies published on the microbiome alone! And we still have so much more to learn about these mighty microbes.

In a nutshell, the microbiome is made up of trillions of microorganisms, including bacteria, fungi, viruses, and parasites. There are 10 times more microbial cells than human cells in the body and 1,000 times more genes in the microbiome than in the human genome. It is estimated that these microbes collectively weigh 3 to 7 pounds! Most of these microbes hang out in the large intestine, but also exist on the skin and lesser amounts in other areas of the body.

What Are the Royal Duties of the Microbiome?

So what do these microbes do in our bodies? To make it simple, most of what happens in our body and our brain is affected by our gut microbiome. Here is a sample of how the microbiome rules our health:

  • It’s in charge of our immune system.

Scientists estimate that 75-80 percent of our immune system resides in our gut. This is due to the microbiome’s major regulation of immune system function. When the quantity and variety of our microbes are out of whack (scientifically called dysbiosis), we are at higher risk of getting infections, autoimmune disorders, chronic inflammatory conditions, and cancer. The good news is that when our microbial balance is corrected through dietary and lifestyle strategies, then immune system function improves!

  • It chooses our mood.

Have you ever had a “gut feeling” about something? That term is now backed by science. It is true that our gut is closely tied to our brain function and emotions via the gut-brain axis. There is a constant two-way communication between our brain and our gut via the vagus nerve. When our microbes are out of balance, it can lead to moodiness, brain fog, or more severe conditions such as anxiety and depression.

  • It controls our hormones.

Who would have thought that microbes in our gut could produce hormones? Thinking back to biology class, isn’t that the job of the endocrine system? Cells in the gut lining produce multiple hormones that impact blood sugar regulation, fat storage, and appetite. Gut microbes can influence the release of these hormones and therefore impact our own blood sugar control, fat storage capability, and appetite control. Have you ever felt like your appetite is out of control? There could be many contributing factors to this, but think about taking care of your gut microbiome as one part of the solution.

Estrogen is another hormone influenced by these little bugs. A collection of microbes in your gut called the estrobolome can impact the level of circulating estrogen in your body. If the estrobolome is out of balance, then this can affect your mood, libido, weight, and other estrogen-related symptoms and conditions.

  • It may affect whether we gain or lose weight.

Many studies have linked an imbalance in the gut microbiome to weight gain and obesity. Scientists have identified certain species of microbes that tend to be out of balance in obese individuals versus those of a healthy weight. A greater diversity of microbes in the gut has been shown to have a preventative effect on long-term weight gain. More research is needed in this area to determine exactly how microbes may affect weight gain, but the science is trending towards the microbes controlling the scale.

  • It produces some key vitamins in our body.

Our gut bacteria produce some B vitamins, such as thiamin, folate, riboflavin, pantothenic acid, and biotin as well as vitamin K. In fact, it is estimated that our microbes produce up to half of our daily vitamin K requirements. We still need to consume these nutrients in our food because our daily needs are higher than what the microbes can produce. However, their production of nutrients contributes to our overall health.

  • It dictates the health of our digestion and bowel regularity.

This point was saved for last because you probably knew about this one. But how many people reach for a Tums or Gas-X when they have digestive upset versus taking care of their microbiome? Those mighty microbes have a significant impact on the digestion, absorption, and storage of nutrients in our body.

An imbalance in the microbiome can lead to mild digestive symptoms, such as gas, bloating, occasional constipation, and diarrhea. If the gut microbes are significantly imbalanced, or out of whack for a long time, then more severe digestive problems may occur, such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), intestinal hyperpermeability (i.e., leaky gut), or other digestive disorders.

This is just a short overview of what we currently know about the role of the microbiome in our body. This area of research is incredibly young in the grand scheme of science, so we have much more to learn. In the meantime, it is evident that we all should pay close attention to how our diet and lifestyle may be impacting our gut microbial balance.

King microbiome is ruling our health! The good news is that we can direct the ruler towards healthy digestion, immunity, hormone balance, and improved weight management. Consult a registered dietitian nutritionist (RDN) who specializes in gut health to guide you in achieving a healthy and balanced microbiome.


Lazar V, Ditu L-M, Pircalabioru GG, Gheorghe I, Curutiu C, Holban AM, Picu A, Petcu L and Chifiriuc MC. Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer. Front. Immunol. 2018 9:1830.

Martin AM, Sun EW, Rogers GB, Keating DJ. The Influence of the Gut Microbiome on Host Metabolism Through the Regulation of Gut Hormone Release. Front Physiol. 2019;10:428.

Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev. 1997 Mar;6 Suppl 1:S43-5.

NIH Human Microbiome Project -

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