Of the 100 trillion bacteria and other microorganisms we have in the body, more than 90% of them are in the gut. If we were to weigh them, we’d find that they weigh almost 6 pounds. Each inch of the large intestine holds over 2.5 billion bacteria, which makes the microbiome in the large intestine the most complicated system in the human body.
Imagine the African Savannah in Africa. It is a made up of different varieties of grasses, shrubs, trees, herbivores, carnivores, birds, and insects that make up a whole ecosystem. In this way, the large intestine, different bacteria, the archaea, fungi, viruses, etc. are trying to get nutrients in the same living space to survive and grow.
Just like in Africa, the microbiome in the gut has a very diversified system. The bacterial population in the intestine changes every 24 to 72 hours. This happens when food passes through the intestines. Some bacteria are excreted in the stool and the rest continue to multiply.
We are living with many bacteria within us but what does it mean?
Today it is believed that every cell in our body has 1.3 cells of bacteria. This means our bodies are actually made up of more bacteria cells than human cells, with roughly 57% of our body's cells being bacteria cells!
When we examine the DNA, the hereditary material tells us something amazing. Every human cell in our body has about the same 20,000 genes, but the total DNA of the microbiome contains 2-20 million different genes. All are within us, most of them in the large intestine!
That means, only one percent of the genes in our body belongs to us and the other 99% belong to the microbiome. This means that our microbiome has a huge affect on our health. Scientists are learning more and more about our microbiome to help us better understand and harness the power of it!