Postbiotics are bioactive compounds produced by probiotic bacteria during fermentation. They play a crucial role in supporting gut health and overall well-being, even after the living bacteria are no longer active. Key postbiotics, such as butyric acid, acetic acid, lactic acid, and propionic acid, offer various health benefits, including:
Key Highlights:
- Energy Provision: Postbiotics like butyric acid provide energy to intestinal cells and support efficient gut function.
- Anti-Inflammatory Effects: They help reduce inflammation and contribute to a healthy immune response.
- Gut Barrier Strengthening: Postbiotics enhance the integrity of the intestinal barrier, which is essential for keeping harmful substances out.
- Production of Neurotransmitters: Certain postbiotics support the production of compounds like serotonin and GABA, contributing to emotional well-being and stress reduction.
These combined functions make postbiotics essential for resilient gut health, optimizing digestion, and supporting energy, immunity, and mental balance.
Why choose postbiotics?
In this document postbiotics are listed that, in principle, could be generated by bacterial strains in YIXIY. The following bacterial strains have been considered:
Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium lactis, Lactobacillus casei, Lactobacillus salivarius, Lactococcus lactis and Streptococcus thermophilus.
For each postbiotic, the bacterial strains are listed which could potentially generate this postbiotic and are present in YIXIY (i.e. the bacterial strains are present in YIXIY, the amount of postbiotic would need to be quantified at e.g. a lab to determine its presence/quantity. Both the presence and quantity are required to determine whether there could potentially be any health effects).
NB I: The involvement of the bacterial strains has not been verified in all cases by scientific articles. The reference has been mentioned in case a specific scientific article was consulted.
NB: In general in this research, it is relevant to be careful with in-vivo (in a living organism) versus in vitro (e.g. in a petri-dish or medium) applications. E.g. if a bacterium shows to lower cholesterol in a petri-dish, it does not automatically mean that this will also happen inside the human body. The petri-dish is a very isolated environment, in the complex human body there may be other processes that inhibit this process e.g. hampering this decrease of cholesterol.
Short-Chain Fatty Acids (SCFAs)
Short-Chain Fatty acids (SCFAs) are produced by gut microbiota from indigestible food components (such as fibers and certain sugar derivations) (Teame et al., 2020).
- Lactic Acid
Function: pH regulation (low pH), inhibition of pathogens, mucosal barrier support, nutrient absorption & modulation of immune response)- Bifidobacterium longum
- Lactobacillus acidophilus
- Lactobacillus rhamnosus
- Bifidobacterium lactis
- Lactobacillus casei
- Lactobacillus salivarius
- Lactococcus lactis
Streptococcus thermophilus
- Acetate
Function: Energy source for colonocytes (cells lining the colon), pH regulation (low pH), gut motility, anti-inflammatory- Bifidobacterium longum
- Lactobacillus acidophilus
- Lactobacillus rhamnosus
- Bifidobacterium lactis
- Lactobacillus casei
- Lactobacillus salivarius
- Lactococcus lactis
Streptococcus thermophilus
- Propionate
Regulation of blood sugar levels, cholesterol metabolism, anti-inflammatory effects, appetite regulation, gut barrier function- Lactobacillus rhamnosus (LeBlanc et al., 2017) (article shows propionate production by this strain)
NB: Butyrate may also be an available postbiotic, but in principle one would expect to find this compound at (even) lower quantities.
Conjugated linoleic acid (CLA)
Function: Described for anticarcinogenic effects (anti-cancer) in animal studies (Belury, 2002; Kim & Park, 2003)
- Lactobacillus acidophilus
- Lactobacillus rhamnosus
Neurotransmitters
Gut bacteria can mediate the availability of various neurotransmitters, either by directly producing these or modulating their availability (Barandouzi et al., 2022; Dicks, 2022; Oleskin et al., 2016; Strandwitz, 2018).
- GABA
Function: GABA is the primary inhibitory neurotransmitter in the brain. It can reduce anxiety and promote relaxation- Lactobacillus acidophilus
- Lactobacillus rhamnosus
- Histamine
Function: Histamine is involved in local immune responses and mediates allergic reactions- Lactobacillus acidophilus
- Lactobacillus casei
- Lactobacillus rhamnosus
- Lactococcus lactis (Özoğul et al., 2012) – in vitro
- Streptococcus thermophilus (Özoğul et al., 2012) – in vitro
- Serotonin
Function: Serotonin aids regulation of mood, anxiety and overall emotional well-being. Additionally, it is involved in controlling gastrointestinal motility- Lactococcus lactis (Özoğul et al., 2012) – in vitro
- Streptococcus thermophilus (Özoğul et al., 2012) – in vitro
- Dopamine
Function: Essential for reward, motivation and motor control- Lactococcus lactis (Özoğul et al., 2012) – in vitro
- Streptococcus thermophilus (Özoğul et al., 2012) – in vitro
NB: Potentially, there are microbacteria that are involved in the generation of neurotransmitters. This would require some follow-up literature search.
Bacteriocins
Function: Bacteriocins are proteins produced by bacteria that kill or inhibit the growth of other bacteria. They act like a defense mechanism, allowing the producing bacteria to compete with or eliminate other (pathogenic) microbes in their environment (Riley & Wertz, 2002).
- Acidocin
- Lactobacillus acidophilus
- Bifidocin B
- Bifidobacterium longum
- Caseicins
- Lactobacillus casei
- Salivaricin
- Lactobacillus salivarius
- Nisin
- Lactococcus lactis
- Lacticin 3147
- Lactococcus lactis
- Thermophilin
- Streptococcus thermophilus
Vitamins
- Folate (Vitamin B9)
Function: A.o. involved in red blood cell formation- Bifidobacterium longum
- Lactobacillus casei
- Lactobacillus rhamnosus (LeBlanc et al., 2017)
- Lactococcus lactis (Gu & Li, 2016)
Menaquinone (Vitamin K2)
Function: Contributes to strong bones and adequate blood clotting- Lactococcus lactis (Gu & Li, 2016)
- Lactobacillus salivarius
- Lactobacillus casei
- Riboflavin (Vitamin B2)
- Lactobacillus rhamnosus (LeBlanc et al., 2017)
- NB: Potentially, there are more B vitamins that lactobacilli can generate. This would require some follow-up literature search.
Cell wall components
- Studies confirmed that cell surface components of Lactobacilli are considered as important communicators (effector molecules), as this part of the microbial cell is the first to interact with host cells. Even after bacterial cells are dead, their cell wall components and surface-associated proteins can retain some health functions, particularly related to immune modulation and gut health.
- Peptidoglycan (Teame et al., 2020)
- Teichoic acid (Teame et al., 2020)
- Cell-wall polysaccharides (exopolysaccharides (EPS)) (Teame et al., 2020)
- Cell surface-associated proteins (LPXTG proteins,S-layer proteins, pili proteins, moonlight proteins) (Teame et al., 2020)
NB: In the article of Teame et al., these cell wall components are categorized as para-biotics. However, according to the Nature commission’s definition these may also fall under the postbiotics. “The panel defined a postbiotic as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host. Effective postbiotics must contain inactivated microbial cells or cell components, with or without metabolites, that contribute to observed health benefits.” (Salminen et al., 2021).