What are postbiotics?

In Japan, postbiotics have been available for more than 100 years(1). Pioneered and developed by Professor Tomotari Mitsuoka in Japan,(2) postbiotics in japan are also referred as Lactic Acid Bacteria (LAB) Metabolites or Lactobacillus Fermented Extracts.

Probiotics are "good" bacteria, mostly are LABs, that reside in the human gut and are vital to our health.

Researchers and biologists over the years have been trying to answer a seemingly "naive" question: why do probiotics have health effects given the fact that probiotics itself just living microbes and NOT nutrients?

The studies and researches on postbiotics recently has been booming(3), and postbiotics have already been found as the major source of health effects of probiotics.(3) Postbiotics, mainly are inactive microbial cells and functional metabolites secreted by native good bacteria, contains key nutrients such as short-chain fatty acids (SCFAs), small molecule peptides and functional protein. They are suggested (3) effectively to slow down the growth of "bad" bacteria, promote native "good" bacteria for restoring gut flora balance and improving absorption disorders, thus induces various diseases including obesity, constipation, diarrhea, irritable bowel syndrome (IBS), and immune disorders.

「乳酸菌の菌体成分や代謝物質が腸を刺激し、腸内フローラを改善することで「腸替免疫」を活性化させるのですから、代謝産物も重要な成分です。」The microbial components and metabolites of lactic acid bacteria stimulate the intestines and improve the intestinal flora, which activates the "intestinal immunity", so metabolites are also key factor for health and with important health effect.

Professor Tomotari Mitsuoka

Bacterial taxonomy, microbial biology Professor Emeritus, University of Tokyo Honorary Scientist, RIKEN

IBS | Chronic Diarrhea Relief
"Moreover, most studies found positive effects for the use of postbiotics on diverse primary outcomes, especially for gastrointestinal functioning and in the treatment of chronic diarrhea or diarrhea predominant IBS" (3)
Constipation Relief
"Subjective and objective Bristol stool scale scores, output and color tone were improved in the postbiotic group, especially in the subgroup of people with a tendency towards constipation"(3)
Skin Severity Relief
"One study investigated the effect of postbiotic L. paracasei K71 versus a placebo in adults, aged 20–65, on atopic dermatitis. Skin severity scores were significantly improved after 8 and 12 weeks in the intervention group, but not in the placebo group" (3)
Immunity boost
"The molecular mechanisms underlying the effects of postbiotics seem to be mediated through an interaction between the host and microbial products. This in turn can trigger the host immune system, and thereby trigger e.g., anti-inflammatory responses" (3)
(1)The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Gastroenterology & Hepatology Vol. 18 Sep 2021
(2)Mitsuoka, T. Intestinal Flora and Probiotics (Gakkai Shuppan Center, 1998)
(3)Postbiotics and their applications in early life nutrition and beyond. Int J Mol Sci. 2019; 20(19):4673