Where is the human microbiome most densely populated?

The human colon is where the body’s densest microbial community is found. It is home to trillions of microorganisms, including bacteria, archaea, fungi, and viruses, with the microbial count far exceeding that of most other body sites. These microbes help break down complex carbohydrates, produce certain vitamins, and influence immune function. The gut microbiome varies from person to person and is shaped by diet, age, medication, and environment. Research on the microbiome has become a major field in medicine and biology over the past two decades.