B. longum BB536 — The Microbiome Stabiliser

Bifidobacterium longum BB536 is a human-residential probiotic strain that modulates the gut microbiome and intestinal environment. It ferments carbohydrates to produce short-chain fatty acids (SCFAs), primarily acetate, which lower luminal pH and inhibit the growth of pathogenic bacteria. Acetate also stimulates the growth of butyrate-producing bacteria, further supporting colonocyte health and intestinal barrier integrity. BB536 produces postbiotics such as indole-3-lactic acid (ILA), which activates the aryl hydrocarbon receptor (AhR) to reduce inflammation and enhance barrier function. Systemically, these metabolites can influence lipid metabolism and immune homeostasis, potentially mitigating age-related dysbiosis and chronic low-grade inflammation (inflammaging).

Multiple human trials demonstrate B. longum BB536 improves gut environment, immune function, and metabolic parameters. In elderly populations, supplementation (up to 50 billion CFU/day) has been shown to improve chronic constipation and modulate the gut microbiota. A 2024 randomised controlled trial found that 10 billion CFU of BB536 combined with B. breve MCC1274 significantly reduced abdominal visceral fat area and serum triglycerides over 16 weeks in healthy overweight adults. No published human longevity trials exist.

10 to 50 billion colony-forming units (CFU) per day is the most studied range in humans. Often administered as a daily capsule or powder, or incorporated into fermented milk products. Best taken with or shortly before meals to improve survival through gastric acid. Unestablished for direct longevity extension, but used continuously in trials for metabolic and immune support.

Generally recognised as safe (GRAS) with a long history of human use. Clinical trials report no serious adverse effects, with excellent tolerability even at high doses (up to 50 billion CFU/day). As with all live biotherapeutics, caution is advised in severely immunocompromised individuals, those with central venous catheters, or patients at risk of bacterial translocation, though BB536 has not been associated with such events in healthy or elderly populations.

Key Papers