The gut microbiome consists of a diverse ecosystem of bacteria, archaea, fungi, and viruses that significantly influences our health and metabolic responses.

A healthy microbiome supports the immune system, metabolism, and gut-brain axis, but defining what constitutes a healthy versus unhealthy microbiome is complex and varies between individuals and populations.

The Human Microbiome Project aimed to define healthy versus diseased microbiomes by studying diverse populations, revealing significant individuality in gut microbiomes and the challenges in establishing universal health standards. Additionally, the microbiomes of traditional populations represent the closest approximation to how our ancestors lived, suggesting that our current industrialized microbiome may be deteriorating due to factors like antibiotic use and a Western diet.

The gut microbiome is incredibly dense, with estimates suggesting that 30% to 50% of fecal matter is made up of microbes, comprising hundreds to thousands of species, primarily bacteria, but also archaea, eukaryotes, and viruses.

A high diversity of the microbiome is associated with a healthy host, suggesting that exposure to various environments, like letting children eat dirt or having pets, can contribute to a healthy microbiome.

The gut microbiome consists of trillions of microorganisms throughout the entire digestive tract, not just the stomach, and includes communities in the nose and on the skin, which are beneficial for our hormonal health, brain health, and immune system function.

The Human Microbiome Project documented the microbiome of healthy Americans, but it may have actually recorded a perturbed microbiota that predisposes individuals to inflammatory and metabolic diseases.

The human microbiome plays a crucial role in how individuals respond to nutrition, and it can be altered, unlike genetics, which opens up possibilities for improving health through dietary changes.

We observed significant changes in participants' microbiomes in response to good and bad diets, aligning with existing literature on beneficial and harmful bacteria.