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Cited by 535Probiotics and Fermented FoodsGut microbiota and healthAnimal Nutrition and Physiology

Probiotics Regulate Gut Microbiota: An Effective Method to Improve Immunity

Open access
Wang, Xinzhou, Zhang, Peng, Zhang, Xin·2021·Molecules
DOI 10.3390/molecules26196076PMC PMC8512487
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Abstract

Probiotics are beneficial active microorganisms that colonize the human intestines and change the composition of the flora in particular parts of the host. Recently, the use of probiotics to regulate intestinal flora to improve host immunity has received widespread attention. Recent evidence has shown that probiotics play significant roles in gut microbiota composition, which can inhibit the colonization of pathogenic bacteria in the intestine, help the host build a healthy intestinal mucosa protective layer, and enhance the host immune system. Based on the close relationship between the gut microbiota and human immunity, it has become an extremely effective way to improve human immunity by regulating the gut microbiome with probiotics. In this review, we discussed the influence of probiotics on the gut microbiota and human immunity, and the relationship between immunity, probiotics, gut microbiota, and life quality. We further emphasized the regulation of gut microflora through probiotics, thereby enhancing human immunity and improving people’s lives.

AI snapshot

Written from the paper’s full text.

TL;DR

This narrative review argues that probiotics regulate gut microbiota composition and thereby improve host immunity through barrier maintenance, pathogen inhibition, and immune modulation. It also links gut microbiota and probiotics to obesity, sleep, and skin conditions as examples of immunity-related quality-of-life outcomes.

Key findings

  • Probiotics can shift gut microbiota composition: in obese animals, probiotic treatment decreased Firmicutes and increased Actinobacteria, and probiotic-treated mice showed increased beneficial bacteria such as Oscillibacter and Prevotella and increased short-chain fatty acid concentrations.
  • Probiotics support the epithelial barrier and inhibit pathogens: examples include *L. plantarum* BMCM12 extracellular proteins weakening pathogen adhesion, VSL#3 or *L. rhamnosus* GG maintaining epithelial barrier integrity, probiotic *E. coli* Nissle 1917 secreting DegP to inhibit enterohemorrhagic *E. coli*, and *Bacillus* isolates inhibiting *S. aureus* colonization via Agr signaling interference.
  • Gut microbiota is required for normal immune development: germ-free mice had significantly lower ovalbumin-specific antibody titers than untreated controls, absent mucous layer, altered IgA secretion, and defective gut-associated lymphoid tissue development.
  • The review reports links between immunity, sleep, and microbiota: after influenza vaccination, subjects sleeping 8 h/day had twice the influenza virus-specific antibody concentration measured 10 days after vaccination compared with subjects sleeping 4 h/day; sleep fragmentation decreased gut microbiota diversity, while *Lactobacillus casei* strain Shirota improved sleep duration and quality.

Methods

  • Narrative review of existing literature on probiotics, gut microbiota, and immunity; no primary experiments or systematic review protocol are described.
  • Synthesizes animal and human studies, including germ-free mouse models, probiotic supplementation trials, vaccination studies, and disease examples such as allergy, colorectal cancer, depression, obesity, sleep, and skin disorders.
  • Main analysis is qualitative: mechanisms and disease associations are discussed without meta-analysis or quantitative pooling.

Limitations

  • The paper does not state limitations.
  • Evident from the text: as a narrative review, it lacks systematic search and inclusion criteria, risk-of-bias assessment, and meta-analysis.
  • Many cited findings come from animal models or associative human studies, and the review does not report primary sample sizes or effect estimates for most claims.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/molecules26196076

Cites

106 of 106 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 75 cited sources checked · 0 supported · 0 flagged

  • Premisenone given

    Probiotics can inhibit the colonization of pathogenic bacteria in the intestine.

    “which can inhibit the colonization of pathogenic bacteria in the intestine”
    Quote in the paperNot a substantial claim
  • Premisereasoning

    Probiotics enhance the host immune system.

    “and enhance the host immune system”
    Quote in the paperSubstantial claim
  • Interpretationreasoning

    Regulating the gut microbiome with probiotics is an extremely effective way to improve human immunity.

    “Based on the close relationship between the gut microbiota and human immunity, it has become an extremely effective way to improve human immunity by regulating the gut microbiome with probiotics.”
    • Also stated in: § 1. Introduction · plain
      “using probiotics to regulate intestinal bacteria has become an effective way to improve immunity”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Findings from animal models and in vitro studies about probiotics, gut microbiota, and immunity can be extrapolated to humans.
    • Rests on an assumption: Effects of specific probiotic strains studied can be generalized to probiotics as a class.
  • Premisenone given

    Probiotics play significant roles in gut microbiota composition.

    “Recent evidence has shown that probiotics play significant roles in gut microbiota composition”
    Quote in the paperSubstantial claim
  • Premisecitation

    Probiotics play an essential role in maintaining human health.

    “a large number of studies have proven that probiotics play an essential role in maintaining human health.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [3] Patra, 2018, Benefaction of probiotics for human health: A review, J. Food Drug Anal. source

      Not checked in the free run.

  • May combine two claims. 17
  • Classified as probably not a substantial claim. 4

  • May combine two claims.

    Premisecitation

    Probiotics mainly exist in the human intestines and can play a beneficial role in the host by maintaining the balance of intestinal microbes.

    “Probiotics mainly exist in the human intestines and can play a beneficial role in the host by maintaining the balance of intestinal microbes [2].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [2] Stavrou, 2017, Gut microbiome, surgical complications and probiotics, Ann. Gastroenterol.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Probiotics can have an anti-obesity effect.

    “probiotics can also have an anti-cancer, anti-obesity, and anti-diabetes effect [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Patra, 2018, Benefaction of probiotics for human health: A review, J. Food Drug Anal. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Probiotics can have an anti-cancer effect.

    “probiotics can also have an anti-cancer, anti-obesity, and anti-diabetes effect [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Patra, 2018, Benefaction of probiotics for human health: A review, J. Food Drug Anal. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    SCFAs produced by intestinal microorganisms can reach other organs, act on antigen-presenting cells, and reduce inflammation in related diseases.

    “and reach other organs, acting on antigen-presenting cells, and reducing inflammation in related diseases [5].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5] Rooks, 2016, Gut microbiota, metabolites and host immunity, Nat. Rev. Immunol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Probiotics can strengthen the intestinal barrier, regulate mucosal immune function, and produce metabolites beneficial to the host to maintain health.

    “There is substantial evidence that probiotics can strengthen the intestinal barrier, regulate mucosal immune function, and produce metabolites beneficial to the host to maintain health, as illustrated in Figure 1 [22,23].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [22] Bron, 2017, Can probiotics modulate human disease by impacting intestinal barrier function?, Brit. J. Nutr. source

      Not checked in the free run.

    • cites [23] Cazorla, 2019, Beneficial effects of probiotic consumption on the immune system, Ann. Nutr. Metab. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Probiotics can have an anti-diabetes effect.

    “probiotics can also have an anti-cancer, anti-obesity, and anti-diabetes effect [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] Patra, 2018, Benefaction of probiotics for human health: A review, J. Food Drug Anal. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Treatment with probiotics can reverse intestinal flora dysbiosis and treat inflammatory responses in mice.

    “Treatment with probiotics can reverse intestinal flora dysbiosis and treat inflammatory responses in mice.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [16] Bagarolli, 2017, Probiotics modulate gut microbiota and improve insulin sensitivity in DIO mice, J. Nutr. Biochem. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Probiotics can increase the number of macrophages and dendritic cells in lamina propria and enhance their function in the intestine for a period of time.

    “Probiotics can increase the number of macrophages and dendritic cells (DCs) in lamina propria and enhance their function in the intestine for a period of time.”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [23] Cazorla, 2019, Beneficial effects of probiotic consumption on the immune system, Ann. Nutr. Metab. source

      Not checked in the free run.

    • cites [40] Rinaldi, 2018, Gut microbiota and probiotics: Novel immune system modulators in myasthenia gravis?, Ann. N. Y. Acad. Sci. source

      Not checked in the free run.

    • cites [41] Frei, 2015, Prebiotics, probiotics, synbiotics, and the immune system: Experimental data and clinical evidence, Curr. Opin. Gastroenterol. source

      Not checked in the free run.

    • cites [42] Shi, 2017, Interaction between the gut microbiome and mucosal immune system, Mil. Med. Res.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The intestinal microbiome is closely related to host immunity and plays an important role in the immune system.

    “In general, the intestinal microbiome is closely related to host immunity and plays an important role in the immune system [47].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [47] Wu, 2012, The role of gut microbiota in immune homeostasis and autoimmunity, Gut Microbes source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Specific species of bacteria may affect both the risk of colorectal cancer and the growth of existing tumors.

    “The study found that specific species of bacteria may affect both the risk of colorectal cancer and the growth of existing tumors [66].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [66] Wieczorska, 2020, The role of the gut microbiome in colorectal cancer: Where are we? Where are we going?, Clin. Colorectal. Cancer source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Probiotics can affect the CNS by regulating the intestinal flora and preventing mental diseases through the gut-brain axis.

    “several research findings have shown that probiotics can affect the CNS by regulating the intestinal flora and preventing mental diseases through the gut–brain axis [71,72,73].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [71] Osadchiy, 2019, The gut-brain axis and the microbiome: Mechanisms and clinical implications, Clin. Gastroenterol. Hepatol. source

      Not checked in the free run.

    • cites [72] Morkl, 2020, Probiotics and the microbiota-gut-brain axis: Focus on psychiatry, Curr. Nutr. Rep. source

      Not checked in the free run.

    • cites [73] Kim, 2018, Mind-altering with the gut: Modulation of the gut-brain axis with probiotics, J. Microbiol. source

      Not checked in the free run.

    • Rests on an assumption: Findings from animal models and in vitro studies about probiotics, gut microbiota, and immunity can be extrapolated to humans.

  • May combine two claims.

    Interpretationreasoning

    Intestinal flora can prevent local inflammation of adipose tissue by preventing obesity and enhancing immunity.

    “Intestinal flora can prevent local inflammation of adipose tissue by preventing obesity and enhancing immunity.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Findings from animal models and in vitro studies about probiotics, gut microbiota, and immunity can be extrapolated to humans.

  • May combine two claims.

    Premisenone given

    Beneficial microorganisms in the intestine can enhance immunity, and the improvement of immunity helps prevent the occurrence of depression.

    “Recently, it has been proven that these beneficial microorganisms in the intestine can enhance immunity, and the improvement of immunity helps prevent the occurrence of depression.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Findings from animal models and in vitro studies about probiotics, gut microbiota, and immunity can be extrapolated to humans.

  • May combine two claims.

    Premisecitation

    Gut microbiota diversity decreases because of sleep fragmentation, but increases due to good sleep quality and enough sleep time.

    “Smith et al. [90] demonstrated that the diversity of the gut microbiota would decrease because of sleep fragmentation, but increase due to good sleep quality and enough sleep time.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [90] Smith, R.P., Easson, C., Lyle, S.M., Kapoor, R., Donnelly, C.P., Davidson, E.J., Parikh, E., Lopez, J.V., and Tartar, J.L. (2019). Gut microbiome diversity is associated with sleep physiology in humans. PLoS ONE, 14. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Regulating intestinal microorganisms by measures such as adjusting daily diet or taking probiotics can enhance immunity and improve sleep quality.

    “We can take some measures, such as adjusting our daily diet or taking probiotics to purposefully regulate the composition of our intestinal microorganisms, to enhance immunity and, ultimately, improve the quality of our sleep.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Short-term sleep control has little effect on intestinal microbial diversity, but intestinal microbial diversity can have a long-term impact on sleep quality.

    “short-term sleep control has little effect on intestinal microbial diversity, but intestinal microbial diversity can have a long-term impact on sleep quality.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [90] Smith, R.P., Easson, C., Lyle, S.M., Kapoor, R., Donnelly, C.P., Davidson, E.J., Parikh, E., Lopez, J.V., and Tartar, J.L. (2019). Gut microbiome diversity is associated with sleep physiology in humans. PLoS ONE, 14. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The gut flora of patients with psoriasis was severely dysregulated, the diversity of certain bacterial taxa reduced, and the abundance altered.

    “the gut flora of patients with psoriasis was severely dysregulated, the diversity of certain bacterial taxa reduced, and the abundance altered.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [100] Gomez, 2019, Gut microbiota dysbiosis in a cohort of patients with psoriasis, Br. J. Dermatol. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The number of Firmicutes and Actinobacteria in the gut microbiota of patients with psoriasis increased significantly, but Proteobacteria and Bacteroides decreased.

    “The number of Firmicutes and Actinobacteria in the gut microbiota of patients with psoriasis increased significantly, but Proteobacteria and Bacteroides decreased.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [100] Gomez, 2019, Gut microbiota dysbiosis in a cohort of patients with psoriasis, Br. J. Dermatol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Probiotics can improve host immunity by maintaining the epithelial barrier, inhibiting pathogens from adhering to the intestinal surface, and modulating and properly maturing the immune system.

    “Probiotics can improve host immunity by maintaining the epithelial barrier, inhibiting pathogens from adhering to the intestinal surface, and modulating and properly maturing the immune system.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Probiotics can regulate the composition of intestinal flora and enhance immunity.

    “probiotics can regulate the composition of intestinal flora and enhance immunity.”
    Quote in the paperNot a substantial claim
20 of 20

  • The paper relies on this without support.

    Findings from animal models and in vitro studies about probiotics, gut microbiota, and immunity can be extrapolated to humans.

    “Based on the close relationship between the gut microbiota and human immunity, it has become an extremely effective way to improve human immunity by regulating the gut microbiome with probiotics.”

  • The paper relies on this without support.

    Effects of specific probiotic strains studied can be generalized to probiotics as a class.

    “In general, probiotics are considered to be dietary factors that can influence the human gut microbiota and also have a regulatory effect on the composition and structure of the intestinal flora.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Successful gut microbiota modulation relies on colonizing viable probiotic bacteria in the intestine.

    “Successful gut microbiota modulation relies on colonizing viable probiotic bacteria in the intestine.6”

    From Gut microbiota drives structural variation of exogenous probiotics to enhance colonization (2025) · cites this paper as [6]

    The Introduction defines probiotics as live microorganisms and says they maintain the balance of intestinal microbes. Section 2.1 reports that probiotics regulate intestinal flora, but the paper does not say that successful modulation requires viable probiotic bacteria to colonize the intestine. The claim turns a described effect into a requirement. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

  • The gut flora mediates three pathways connected to the pathogenesis of obesity and diabetes: low-grade inflammation, raised blood levels of lipopolysaccharides (endotoxemia), and increased energy harvest.

    “The gut flora mediates three pathways connected to the pathogenesis of obesity and diabetes: low-grade inflammation, raised blood levels of lipopolysaccharides (endotoxemia), and increased energy harvest.”

    From A critical review on diabetes mellitus type 1 and type 2 management approaches: from lifestyle modification to current and novel targets and therapeutic agents. (2024) · cites this paper as [112]

    Section 4.1 (page unavailable) links gut microbiota to obesity and describes local adipose-tissue inflammation that can become systemic. It does not identify the claimed three pathways: it does not address raised blood lipopolysaccharides or increased energy harvest, or establish those pathways for diabetes. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Citation [101] is attributed to Scher et al.

    Minor

    The text names Scher et al. as the authors of reference 101, which instead lists Myers et al.

  • Citation [102] is attributed to Masallat et al.

    Minor

    The text attributes reference 102 to Masallat et al., but the listed reference is by Yan et al.

  • Opposite Actinobacteria findings are described as the same result

    Minor

    The text first says Actinobacteria increased significantly in patients with psoriasis, then calls a finding that Actinobacteria were less abundant in patients than in healthy controls "the same results."

  • Citation [26] is attributed to a different author

    Minor

    The text attributes citation [26] to Caballero-Franco et al., but reference 26 lists Monteagudo-Mera et al.

4 of 4

Cites

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Related

Authors
Wang, X., Zhang, P., & Zhang, X.
Affiliations
  • Department of Food Science and Engineering, Ningbo University, Ningbo 315211, China
  • Xinyang Normal University (CN)
  • Ningbo University (CN)
Corresponding author
  • Zhang, Peng
  • Zhang, Xin
ORCID
Venue
Molecules
Publisher
MDPI AG
Published
2021-10-08
Volume
26
Issue
19
Pages
6076
ISSN
1420-3049 (ISSN-L)
DOI
10.3390/molecules26196076
PMC
PMC8512487
OpenAlex
W3204396902
Semantic Scholar
2528d2ab806835eaa8f011b3a7fea6704fc9ab8e
Cited by
529
References
106
Citations by year
2026: 87 · 2025: 170 · 2024: 162 · 2023: 75 · 2022: 35
FWCI
6.36
Type
journal article
Language
en
Open access
Licence
Locations
  • Molecules (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
the Key Research and development program of Zhejiang Province (2018C02023)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Probiotics and Fermented Foods
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Gut microbiota and health
  • Life Sciences › Agricultural and Biological Sciences › Animal Science and Zoology › Animal Nutrition and Physiology
Keywords
probiotics, gut microbiota, host immunity, quality of life
MeSH terms
Gastrointestinal Microbiome, Bacteria, Humans, Immune System, Probiotics

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

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