Postbiotics

Postbiotics relate to dead bacteria and their by-products, which can also have beneficial affects on the gut in addition to their live counterparts.

Parts of dead bacteria cell walls called bacterial polysaccharides are complex carbohydrates abundant in fermented foods such as kimchi and sauerkraut that communicate with gut immune cells, regulating immune responses and supporting the integrity of the gut barrier. Emerging research suggests that this can strengthen intestinal lining, reduce low-grade inflammation and promote immune balance.

By products of bacteria called bacterial metabolites include nutrients for example, B vitamins (like B12, B6, and folate), which help with the conversion of food into energy, support healthy nerve function, brain function including balancing mood, overall metabolic health and aid communication between the gut and the brain.

Fibre rich and fermented foods such as fermented vegetables and dairy can support growth of these bacteria along with their by-products which can continue to support health even when the bacteria are no longer alive.

(1)

Further Reading And References

(1) Louise Pyne: Why dead bacteria are the secret to a happier gut, The Standard, 3 February 2026