Key Species - Faecalibacterium

Faecalibacterium prausnitzii is one of the most abundant and beneficial bacteria in the adult human gut. It acts as the main "fuel factory" for your colon, producing large amounts of butyrate. Its presence at high levels is a very reliable indicator of a healthy, inflammation-free gut, while its disappearance is the characteristic signature of inflammatory diseases such as Crohn's disease.

This bacterium feeds on the plant fiber that you cannot digest (like that from legumes or fruits) and transforms it into butyrate.

Butyrate is the preferred energy source for the cells lining your colon (colonocytes). Without F. prausnitzii, these cells "starve", weaken, and stop repairing the intestinal wall, allowing cracks to form (permeability). Furthermore, this bacterium is extremely shy of oxygen (strict anaerobe); if there is inflammation and oxygen in the intestine, it dies quickly, so its mere presence confirms if your intestinal environment is stable and healthy.

It is the most potent natural anti-inflammatory agent in your ecosystem:

• Colon Nutrition: It provides up to 70% of the energy your colon cells need to regenerate and stay healthy.
• Anti-inflammatory Shield: It secretes specific proteins (like MAM) that block cellular inflammation pathways (NF-kB) and stimulate the production of IL-10, a molecule that calms the immune system.
• Disease Prevention: Low levels are consistently associated with Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), colorectal cancer, and depression.
• Allergy Protection: It also helps maintain immune tolerance, preventing exaggerated reactions to food or environmental allergens.

F. prausnitzii belongs to the phylum Firmicutes. It is an obligate anaerobe and extremely sensitive to oxygen, which makes its detection through traditional cultures very difficult and makes metagenomics the tool of choice for its quantification.

The analysis evaluates the relative abundance of this species by Shotgun sequencing. Unlike other bacteria that can fluctuate rapidly, F. prausnitzii is usually very stable in healthy adults, representing a significant fraction of the total biomass. Its optimal range is 5% - 15% relative abundance and it is normal for it to be the dominant species.