Probiotics - Benefits, Safety, Risks, Mechanisms
Intro/guide for probiotic supplementation:
https://humanmicrobiome.info/probiotic-guide - additional links here, and on the Maternity page.
General:
Review, 2019: Probiotics in Extraintestinal Diseases: Current Trends and New Directions https://www.mdpi.com/2072-6643/11/4/788/htm
"As stated before, the ability to adhere and colonize the intestine highly depends on the specific bacterial strain tested, and this is the reason for many conflicting data about fecal recovery of probiotic bacteria." -A Consumer’s Guide for Probiotics: 10 Golden Rules for a Correct Use
The vast majority of probiotics do not colonize (2001): http://ajcn.nutrition.org/content/73/2/399s.full | Some do in some people: https://doi.org/10.1016/j.chom.2016.09.001 - https://archive.is/BLZzv
Recent (7-22-2016) study that refutes the claim that probiotics have no affect on the intestinal microbial ecosystem of healthy adults: http://aem.asm.org/content/early/2016/07/18/AEM.01753-16.abstract || Same result with b.infantis 35624 (Align): http://www.tandfonline.com/doi/abs/10.4161/gmic.24196 || Related study: No differences to bowel movements, stool consistency or microbiota composition. But they did affect the fecal molecular profile (2018): http://www.mdpi.com/2072-6643/10/2/195/htm | Another 2018 one: http://www.jnmjournal.org/journal/view.html?uid=1404&vmd=Full& Effects of the Administration of Probiotics on Fecal Microbiota Diversity and Composition in Healthy Individuals. The proportion of fecal microbiota at the genus level is significantly altered by the administration of probiotics.
"The probiotic treatment significantly altered the fecal microbiota, but taxonomic analyses showed no direct association between ingestion of probiotic bacteria and their abundance in fecal microbiota. These results suggest that probiotics indirectly alter the intestinal microenvironment" (2018): https://www.biorxiv.org/content/biorxiv/early/2018/04/20/304956.full.pdf
Even heat-killed bacteria can have an impact [1][2][3][4][5][6][7].
2017 update to the 2015 Yale probiotic workshop: https://doi.org/10.1016/j.gtc.2017.09.011
Site run by a nutritionist that seems quite good: http://www.powerofprobiotics.com/Probiotic-supplements.html
Consume probiotics with meal or prior to meal [1][2][3][4]. Calcium phosphate absorbs bile acids and increases probiotic survivability. Calcium carbonate does not: http://www.wageningenacademic.com/doi/pdf/10.3920/BM2014.0168
The underexposed role of food matrices in probiotic products: Reviewing the relationship between carrier matrices and product parameters. (2017): https://www.ncbi.nlm.nih.gov/pubmed/28609116
CFU counts in supplements vs fermented foods: https://archive.is/bUJFR
Mixtures more effective than its component strains separately: http://www.ncbi.nlm.nih.gov/pubmed/21229254 – http://www.ncbi.nlm.nih.gov/pubmed/22677262
Most probiotics are labeled inaccurately: https://archive.is/wmEN6
Mechanisms:
Review, 2019: Mechanisms and immunomodulatory properties of pre- and probiotics https://www.wageningenacademic.com/doi/abs/10.3920/BM2018.0066
Treatment With Multi-Species Probiotics Changes the Functions, Not the Composition of Gut Microbiota in Postmenopausal Women With Obesity: A Randomized, Double-Blind, Placebo-Controlled Study (Mar 2022, n=56 obese, postmenopausal women) https://www.frontiersin.org/articles/10.3389/fcimb.2022.815798/full
Probiotics can alleviate depression induced by constipation through protecting neuronal health via activation of the AKT signaling pathway (2018): https://link.springer.com/article/10.1007%2Fs11011-018-0269-4
"increased Bacteroidetes to Firmicutes ratio and elevated abundance of the bacterial family S24-7 (Bacteroidetes), which is known to be associated with butyrate and propanoate production. Altered the intestinal metabolic pathways associated with propanoate and butanoate in the mice. Gene ontology analysis also revealed influencing of many physiological functions related to the defense response. The profiles of various genes associated with antimicrobial peptides-, tight junctions-, adherens junctions- and mucus-associated intestinal barrier functions were also drastically altered" (2018, mice): https://academic.oup.com/intimm/advance-article/doi/10.1093/intimm/dxy035/4996080
Distinct effects of GG and C59 on gene expression in the intact small intestine provide clues to understand how the health beneficial effects of specific strains of probiotic bacteria are mediated by interactions with intestinal cells http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0188985
Four common probiotics related products obviously inhibited human colonic smooth muscles strips contraction in a dose-dependent manner. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0189257
"redox changes in over 450 proteins, many of which are implicated to function in cellular processes such as endosomal trafficking, epithelial cell junctions, barrier integrity, and cytoskeleton maintenance and formation" (2018): https://www.sciencedirect.com/science/article/pii/S221323171830805X
Lactobacillus reuteri HCM2 protects mice against Enterotoxigenic Escherichia coli through modulation of gut microbiota (2018): https://www.nature.com/articles/s41598-018-35702-y
Multiple mechanisms whereby Bifidobacterium bifidum G9-1 (BBG9-1) improves constipation symptoms (Mar 2021, rats): https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0248584
Eczema-protective probiotic alters infant gut microbiome functional capacity but not composition: sub-sample analysis from a RCT (2018): https://www.wageningenacademic.com/doi/abs/10.3920/BM2017.0191
Pathogen (Staphylococcus aureus) elimination by probiotic Bacillus via signalling interference (2018): https://www.nature.com/articles/s41586-018-0616-y
New lactic acid bacteria for skin health via oral intake of heat‐killed or live cells (2018): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6001785/ "The deduced mechanisms associated with the beneficial effects of strain H61 are also discussed"
Antidepressant-like activities of live and heat-killed Lactobacillus paracasei PS23 in chronic corticosterone-treated mice and possible mechanisms (2019): https://doi.org/10.1016/j.brainres.2019.01.025
Ingestion of Bifidobacterium longum changes miRNA levels in the brains of mice (Apr 2021) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249817
Interplay with immune system:
Beneficial Effects of Probiotic Consumption on the Immune System (2019): https://doi.org/10.1159/000496426
Probiotics importance and their immunomodulatory properties (2018): https://doi.org/10.1002/jcp.27559
Bacteria in fermented food signal the human immune system https://www.eurekalert.org/pub_releases/2019-05/p-bif051519.php. Metabolites of lactic acid bacteria present in fermented foods are highly potent agonists of human hydroxycarboxylic acid receptor 3 (May 2019) https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1008145
We found that VSL#3 administration did not lead to any changes in gut flora, but led to a reduction in the frequency of Th17 cells and in the production of pro-inflammatory cytokine on lipopolysaccharide stimulation. These findings suggest that the beneficial anti-inflammatory effect of this preparation in patients with autoimmune and allergic disorders may be related to reduced production of monocyte-derived cytokines rather than to changes in the composition of gut microbiota. (2018): https://bmcgastroenterol.biomedcentral.com/articles/10.1186/s12876-018-0819-6
Oral Administration of Probiotics Increases Paneth Cells and Intestinal Antimicrobial Activity (2018): https://www.frontiersin.org/articles/10.3389/fmicb.2018.00736/full
The analysis of a wide range of immune factors in faecal samples suggests a modulatory effect by these three probiotic strains during the intervention period (2018): https://www.wageningenacademic.com/doi/10.3920/BM2017.0132
Influence of monostrain and multistrain probiotics on immunity, intestinal ultrastructure and microbiota in experimental dysbiosis (2018, rats): https://www.wageningenacademic.com/doi/abs/10.3920/BM2017.0117
Oral supplementation of B. longum strain BR-108 alters cecal microbiota by stimulating gut immune system in mice. Study demonstrated that the effect of heat-killed BR-108 on the mouse cecal microbiota is similar to that of viable BR-108, most likely due to stimulation of the gut immune system https://archive.fo/QKS0V
Importance of probiotic strains:
Answers to Your Questions about Probiotics. Which Strains of Probiotics Should I Look For? https://www.webmd.com/diet/features/answers-to-your-questions-about-probiotics
Strain specific stress-modulating effects of candidate probiotics: A systematic screening in a mouse model of chronic restraint stress (2020) https://www.sciencedirect.com/science/article/pii/S0166432819312604
2017 NIH-wide workshop report on “The Human Microbiome: Emerging Themes at the Horizon of the 21st Century” (2019) https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-019-0627-4 "the clearest next steps called out by the workshop—drilling down to the strain-specific molecular underpinnings"
Genotypic and phenotypic diversity of Lactobacillus rhamnosus clinical isolates, their comparison with strain GG and their recognition by complement system (2017) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0176739
Human milk oligosaccharide consumption by probiotic and human-associated bifidobacteria and lactobacilli (2017) https://www.sciencedirect.com/science/article/pii/S0022030217307300
Probiotic Lactobacillus reuteri has antifungal effects on oral Candida species in vitro (2017) https://www.tandfonline.com/doi/full/10.1080/20002297.2016.1274582 "the results reconfirms that the probiotic capacity of L. reuteri is strain specific"
The Bacteroides fragilis pathogenicity island links virulence and strain competition (2017) https://www.tandfonline.com/doi/full/10.1080/19490976.2017.1290758
Genomic Microdiversity of Bifidobacterium pseudocatenulatum Underlying Differential Strain-Level Responses to Dietary Carbohydrate Intervention (2017) https://journals.asm.org/doi/10.1128/mbio.02348-16
Gut metagenomes of type 2 diabetic patients have characteristic single-nucleotide polymorphism distribution in Bacteroides coprocola (2017) https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0232-3 "results suggest that different strains of B. coprocola may have different roles in human gut and a specific set of B. coprocola strains are correlated with T2D"
Bifidobacteria—Insight into clinical outcomes and mechanisms of its probiotic action (2016, review) https://www.sciencedirect.com/science/article/pii/S0944501316304323
The Impact of Lactobacillus casei on the Composition of the Cecal Microbiota and Innate Immune System Is Strain Specific (2016) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0156374
Time- and strain-specific downregulation of intestinal EPAS1 via miR-148a by Bifidobacterium bifidum (2016) https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201600596
Superantigens and adhesins of infant gut commensal Staphylococcus aureus strains and association with subsequent development of atopic eczema (2016) https://onlinelibrary.wiley.com/doi/abs/10.1111/bjd.15138
Importance of human-sourced probiotics:
Selection criteria for probiotics: A review (Jan 2014) https://www.researchgate.net/publication/288067379_Selection_criteria_for_probiotics_A_review
Each animal species hosts a unique microbial community: https://news.vanderbilt.edu/2016/11/28/each-animal-species-hosts-a-unique-microbial-community-and-benefits-from-it/
Each animal host seems to have a host-specific strain of L. reuteri, e.g. a rat strain for rats, a pig strain for pigs, etc.: https://en.wikipedia.org/wiki/Lactobacillus_reuteri#Prevalence - https://link.springer.com/article/10.1007/BF00584224
A human origin strain Lactobacillus acidophilus DDS-1 exhibits superior in vitro probiotic efficacy in comparison to plant or dairy origin probiotics (2018) https://www.medsci.org/v15p0840.htm
Via rectal enema:
Randomised clinical trial: the effectiveness of Lactobacillus reuteri ATCC 55730 rectal enema in children with active distal ulcerative colitis (2011, n=31) https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2036.2011.04939.x "effective in improving mucosal inflammation and changing mucosal expression levels of some cytokines involved in the mechanisms of inflammatory bowel disease" - note they did not compare with oral administration.
Harms/safety:
Review, 2023: Emerging issues in probiotic safety: 2023 perspectives https://www.tandfonline.com/doi/full/10.1080/19490976.2023.2185034
Review, 2018: Harms Reporting in Probiotics, Prebiotics, and Synbiotics Trials "Harms reporting is often lacking or inadequate. We cannot broadly conclude that these interventions are safe without reporting safety data." http://annals.org/aim/article-abstract/2687953/harms-reporting-randomized-controlled-trials-interventions-aimed-modifying-microbiota-systematic
Probiotic Safety—No Guarantees (viewpoint, Dec 2018): https://sci-hub.tw/https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2702973
Review, 2019: Probiotics: If It Does Not Help It Does Not Do Any Harm. Really? https://www.mdpi.com/2076-2607/7/4/104 "review describes the dark side of the probiotics, in terms of problematic research design, incomplete reporting, lack of transparency, and under-reported safety. Highlighted are the potential virulent factors and the mode of action in the intestinal lumen, risking the physiological microbiome equilibrium. Finally, regulatory topics are discussed"
Dutch trial of probiotics in acute pancreatitis is to be investigated after deaths (2008) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2234554/
Pathogenic relevance of Lactobacillus: a retrospective review of over 200 cases (2004) https://link.springer.com/article/10.1007%2Fs10096-004-1253-y - Lactobacillus was found to be frequently associated with endocarditis and bacteremia. Lactobacillus was also associated with a variety of other infections including, but not limited to, peritonitis, abscesses, and meningitis. The species casei and rhamnosus were the most common. The overall mortality rate was nearly 30%.
Researchers from the University of Vermont (UVM) have found that a species of gut microbiome bacteria called Lactobacillus reuteri—which is commonly used in probiotics— can increase disease severity in a mouse model of multiple sclerosis (MS), but only in genetically susceptible animals (2020) https://www.genengnews.com/news/role-of-gut-microbiome-in-multiple-sclerosis-depends-on-genetic-makeup-study-in-mice-suggests/
Lactobacillus reuteri tryptophan metabolism promotes host susceptibility to CNS autoimmunity (Nov 2022, mice) https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-022-01408-7 "In summary, we find that metabolism of dietary tryptophan by specific gut commensal microbes such as L. reuteri can unexpectedly promote experimental autoimmune disease."
L. reuteri exacerbates TLR7-dependent lupus in conventional and germ-free mice (2018): https://doi.org/10.1016/j.chom.2018.11.009
Probiotics associated with a higher rate of c.diff recurrence (Oct 2017): https://academic.oup.com/ofid/article/4/suppl_1/S384/4295046
Predictors of Clostridium difficile Infection and Predictive Impact of Probiotic Use in a Diverse Hospital-Wide Cohort (Sep 2018, n=5209) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6321775/ "probiotics were independently predictive of CDI"
"The amount of Bifidobacterium genus in colorectal tissue is associated with an increased risk of anastomotic leakage after resection for colorectal cancer" (Nov 2019, n=256 humans) https://www.sciencedirect.com/science/article/pii/S0960740419300465 Mucosal cancer-associated microbes and anastomotic leakage after resection of colorectal carcinoma.
Probiotics (multi strain) enhance susceptibility of mice to cryptosporidiosis (2018): https://doi.org/10.1128/AEM.01408-18
Mothers self-administering probiotics during breastfeeding, as well as directly to their infants, with either random/general probiotics, or BioGaia, resulted in poorer health outcomes and suggests that probiotic exposure during infancy has limited effects on gut microbial composition yet is associated with increased infection later in life. (2018): https://www.nature.com/articles/s41598-018-26423-3
As density of L. reuteri DSM 17938 (BioGaia) was associated with increased crying time, L. reuteri supplementation may not be an appropriate treatment for all infants with colic. https://www.nature.com/articles/s41598-017-15404-7
Consuming probiotics as a counterbalance to any antibiotics being taken could delay normal gut bacteria returning to their original state (2018): https://newatlas.com/gut-microbiota-probiotics-effects/56231/
Saccharomyces cerevisiae exacerbated intestinal disease in a mouse model of colitis and increased gut barrier permeability: https://www.ncbi.nlm.nih.gov/pubmed/28275154
Multi-species, Lactobacillus & Bifidobacteria probiotic causes more deaths than placebo in acute pancreatitis study: https://archive.is/A0088
Some common genera & species used in probiotics are already elevated in some disease states: (2017) https://academic.oup.com/femsec/article-abstract/doi/10.1093/femsec/fix153/4604777 || (2014) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3911339/
Probiotic supplementation (VSL#3) increases obesity with no detectable effects on liver fat or gut microbiota in obese Hispanic adolescents: a 16-week, randomized, placebo-controlled trial (2018): https://www.ncbi.nlm.nih.gov/pubmed/29493105
Case report of fungemia in a patient with Clostridium difficile-associated diarrhoea (CDAD) treated orally with S. boulardii (Codex (Zambon Farmaceutici, Vicenza, Italy)) in association with vancomycin (2014): http://journals.sagepub.com/doi/10.1177/039463201402700120
Seven cases of Saccharomyces fungaemia related to use of probiotics, India (2017): https://onlinelibrary.wiley.com/doi/full/10.1111/myc.12604
Man develops fatal bacterial infection after taking ‘widely used’ probiotic (Aug 2024, C. butyricum MIYAIRI 588) https://forum.humanmicrobiome.info/threads/man-develops-fatal-bacterial-infection-after-taking-widely-used-probio.541/ Probiotics-related Clostridium butyricum bacteraemia after COVID-19, confirmed by whole-genome sequencing.
Eating a lot of fiber could improve some cancer treatments. The same can’t be said for taking probiotics. Probiotic and antibiotic use associated with lower diversity https://www.sciencenews.org/article/eating-lot-fiber-could-improve-some-cancer-treatments. The gut microbiome (GM) and immunotherapy response are influenced by host lifestyle factors (Mar 2019).
Ingestion of Lactobacillus intestinalis and Lactobacillus reuteri causes depression- and anhedonia-like phenotypes in antibiotic-treated mice via the vagus nerve (Aug 2020) https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-020-01916-z
Prescript-assist soil based, spore-forming probiotics: http://www.thecandidadiet.com/soil-based-organisms/ - https://www.amazon.com/review/R1UA8D182MJAIJ (WARNING)
More bad experiences: https://archive.fo/L0R2J
More warnings about soil bacteria:
http://www.powerofprobiotics.com/MegaSporeBiotic.html
D-Lactate:
D-Lactate/D-lactic acid producing bacteria/probiotics can cause problems for some people: https://archive.is/YwnNz | Like CFS patients: http://iv.iiarjournals.org/content/23/4/621.long
D-Lactic acidosis: Popular probiotic (L. acidophilus) may induce neurotoxicity: http://www.mommypotamus.com/popular-probiotic-strain-may-induce-neurotoxicity/
D-Lactate free probiotics:
http://fixyourgut.com/why-supplementing-with-probiotics-may-make-you-ill-part-4-d-lactate
GutPro and Custom probiotics: https://archive.is/d6LB0
D-lactic acidosis PDF with list of D & L lactic acid producers: https://web.archive.org/web/20200922055256/https://www.pdf-archive.com/2016/12/16/d-lactate-values-dr-lord/d-lactate-values-dr-lord.pdf
Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis (2018): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6006167/ A strong rebuttal: ‘Brain Fogginess’ and D-Lactic Acidosis: Probiotics Are Not the Cause (2018): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155354/
But the right probiotics can also eliminate D-Lactic acidosis, even when antibiotics cannot: D-lactic Acidosis: Successful Suppression of D-lactate–Producing Lactobacillus by Probiotics (2018): https://sci-hub.tw/https://doi.org/10.1542/peds.2018-0337 The strains used were L. GG, B. Lactis BS01, B. Breve BR03, B. Longum BL03. Found in this product: https://web.archive.org/web/20180902124727/https://www.spectrumceuticals.net/product/pro4-50-d-lactate-free-multistrain-probiotic-30-capsules/
Why Supplementing With Probiotics May Make You Ill – Part 5: Th1 / Th2 Immune Reactions: http://fixyourgut.com/why-supplementing-with-probiotics-may-make-you-ill-part-5-th1-th2-immune-reactions/
Lactobacillus casei, Histamine Producer or Probiotic? http://www.powerofprobiotics.com/Lactobacillus-casei.html
List of histamine-producing bacteria (p 9/13): http://www.allergynutrition.com/wp-content/uploads/2014/05/Histamine-DAO-and-Probiotics-Revised.pdf
Probiotics that lower histamine: https://web.archive.org/web/20150311195251/http://thelowhistaminechef.com/these-probiotic-strains-lower-histamine-rather-than-raising-it
Screening selected strains of probiotic lactic acid bacteria for their ability to produce biogenic amines (histamine and tyramine) (2011) https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2011.02717.x "This study confirmed that BA formation is strain dependent and not related to the species"
Fermented foods:
New publication clarifies the concept of fermented foods and specifies how they differ from probiotics (Jan 2021) https://www.eurekalert.org/pub_releases/2021-01/isaf-eao010521.php The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods.
Review, 2019: Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease https://www.mdpi.com/2072-6643/11/8/1806/htm "there is very limited clinical evidence for the effectiveness of most fermented foods in gastrointestinal health and disease"
Kefir:
Commercially available kefir ineffective for antibiotic-associated diarrhea (2009): https://jamanetwork.com/journals/jamapediatrics/fullarticle/382013
Probiotic potential and biochemical and technological properties of Lactococcus lactis ssp. lactis strains isolated from raw milk and kefir grains (2019): https://www.ncbi.nlm.nih.gov/pubmed/30391179 "these strains did not possess all of the properties required to meet the definition of a probiotic"
Ability of Lactobacillus kefiri LKF01 (DSM32079) to colonize the intestinal environment and modify the gut microbiota composition of healthy individuals (2017, 1 month) https://www.sciencedirect.com/science/article/pii/S1590865816308155
Benefits:
Mental health: See mental health section.
Vaginal health: See vagina section.
Allergies: See allergies section.
Effects of Heat-Treated Lactobacillus helveticus CP790-Fermented Milk on Gastrointestinal Health in Healthy Adults: A Randomized Double-Blind Placebo-Controlled Trial (Jul 2024, n=120) https://www.mdpi.com/2072-6643/16/14/2191 "significantly improved constipation symptoms and mood"
Consumption of a Fermented Milk Product Containing Bifidobacterium lactis CNCM I-2494 in Women Complaining of Minor Digestive Symptoms: Rapid Response Which Is Independent of Dietary Fibre Intake or Physical Activity (Jan 2019): https://www.mdpi.com/2072-6643/11/1/92/htm - https://www.gutmicrobiotaforhealth.com/how-to-take-care-of-your-digestive-health-a-new-study-shows-that-regular-fermented-milk-consumption-can-improve-mild-digestive-symptoms/
Yogurt improves insulin resistance and liver fat in obese women with nonalcoholic fatty liver disease and metabolic syndrome: a randomized controlled trial (May 2019, n=100) https://academic.oup.com/ajcn/article-abstract/109/6/1611/5499357
Fermented-food diet increases microbiome diversity and decreases markers of inflammation (2021) https://www.cell.com/cell/fulltext/S0092-8674(21)00754-6 Gut-microbiota-targeted diets modulate human immune status.
Kefir:
Review, 2013: Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3833126/
Review, 2016: The Microbiota and Health Promoting Characteristics of the Fermented Beverage Kefir: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4854945/
Review, 2017: Milk kefir: nutritional, microbiological and health benefits: https://doi.org/10.1017/S0954422416000275 "A large proportion of the studies that support these findings were conducted in vitro or in animal models"
Review, 2018: Modern perspectives on the health benefits of kefir in next generation sequencing era: Improvement of the host gut microbiota: https://www.tandfonline.com/doi/abs/10.1080/10408398.2018.1428168 "significant and wide-spectrum modulatory effects on the host gut microbiota"
Detriments:
Administration of probiotic kefir to mice with Clostridium difficile infection exacerbates disease http://www.sciencedirect.com/science/article/pii/S1075996416300610
Lacto-Fermented Foods Linked to Esophageal & Stomach Cancer: https://www.drcarney.com/blog/entry/lacto-fermented-foods-linked-to-esophageal-cancer - https://www.swisshillsferments.com/does-kimchi-cause-stomach-cancer-a-look-at-the-dark-side-of-ferments-part-1/
Epidemiological evidence that kimchi consumption may significantly increase cancer risk: https://web.archive.org/web/20230402113545/https://nutritionfacts.org/video/is-kimchi-good-for-you/
Kimchi and sauerkraut contain carcinogenic putrescine: https://nutritionfacts.org/video/carcinogenic-putrescine/
A Case of Kombucha Tea Toxicity (2009): https://journals.sagepub.com/doi/10.1177/0885066609332963 "Several case reports exist of serious, and sometimes fatal, hepatic dysfunction and lactic acidosis within close proximity to ingestion"
Bacterial and fungal microbiota of spontaneously fermented Chinese products, Rubing milk cake and Yan-cai vegetable pickles https://www.sciencedirect.com/science/article/pii/S0740002017306810 "results suggest that some of these traditional foods are undesirable as ready-to-eat (RTE) foods, even when these are typical lactic acid fermented foods"
Conditions:
Allergies:
Probiotic gives long-standing protection against childhood eczema, study finds. https://medicalxpress.com/news/2018-12-probiotic-long-standing-childhood-eczema.html - Effects of Lactobacillus rhamnosus HN001 in early life on the cumulative prevalence of allergic disease to 11 years (2018): https://doi.org/10.1111/pai.12982
Probiotic B. longum KACC 91563 has ability to reduce effects of food allergies: http://www.news-medical.net/news/20160316/Research-shows-probiotic-B-longum-KACC-91563-has-ability-to-reduce-effects-of-food-allergies.aspx
Bifidobacterium Infantis showed significant protective effect on food allergic mice: http://www.ajtr.org/files/ajtr0035123.pdf
2015 Australian study shows "Lactobacillus rhamnosus CGMCC 1.3724" cures peanut allergy in 80% of children: https://archive.fo/zsQG7
Lactobacillus gasseri KS-13, Bifidobacterium bifidum G9-1, and Bifidobacterium longum MM-2 improve rhinoconjunctivitis-specific quality of life in individuals with seasonal allergies: https://examine.com/nutrition/do-probiotics-improve-quality-of-life-in-seasonal-allergies/
Experimental and clinical evidence has shown that probiotics significantly modulate immune responses and thus suppress allergic reactions http://www.tandfonline.com/doi/abs/10.1080/10408398.2016.1269719
Allergic diseases and probiotics, Jun Kim Ph.D. https://medium.com/@thryve/allergic-diseases-and-probiotics-d258ae5206b6
Fermented foods:
The Antiallergic Effect of [heat-killed] Kefir Lactobacilli (Lactobacillus kefiranofaciens M1) (2010, mice): https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2010.01787.x
C. difficile
Studies offer conflicting evidence on probiotics for CDI prevention (July 2019) https://www.healio.com/pediatrics/gastrointestinal-conditions/news/print/infectious-diseases-in-children/%7B3ee0068e-5691-4bb0-985c-de1f91a751b5%7D/studies-offer-conflicting-evidence-on-probiotics-for-cdi-prevention
Probiotics associated with a higher rate of c.diff recurrence (Oct 2017): http://www.mdmag.com/medical-news/secondary-prophylaxis-did-not-significantly-reduce-cdi-rates
Administration of probiotic kefir to mice with Clostridium difficile infection exacerbates disease http://www.sciencedirect.com/science/article/pii/S1075996416300610
Consortium of Probiotics Attenuates Colonization of Clostridioides difficile (Dec 2019) https://www.frontiersin.org/articles/10.3389/fmicb.2019.02871/full "five Lactobacilli strains, isolated from the feces of healthy breast-feeding infants and Tibet wild marmots. Bifidobacterium adolescentis (ATCC15703) and B. infantis (ATCC 15697), purchased from the American Type Culture Collection (ATCC, United States)"
IBS:
Review, Nov 2019: Gut microbiota and the use of probiotics in constipation in children and adolescents: systematic review http://dx.doi.org/10.1590/1984-0462/2020/38/2018123 "8 clinical trials with heterogeneous methodologies were found. 15 strains of probiotics were evaluated and only 1 was analyzed in more than one article. Irregular beneficial effects of probiotics have been demonstrated in some manifestations of constipation. In one clinical trial, a complete control of constipation without the use of laxatives was obtained." - maybe L. casei rhamnosus Lcr35.
Review, 2010: The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review http://gut.bmj.com/content/59/3/325.short "Probiotics appear to be efficacious in IBS, but the magnitude of benefit and the most effective species and strain are uncertain"
Consumption of a probiotic drink containing L casei, L bulgaricus, and S thermophilus can reduce the incidence of antibiotic associated diarrhoea and C difficile associated diarrhoea (2007) http://www.bmj.com/content/335/7610/80
Multi-species trial shows effective for IBS. A Randomized, Double-blind, Placebo-controlled Trial (2013): http://www.medscape.com/viewarticle/818812_3 - https://onlinelibrary.wiley.com/doi/abs/10.1111/jgh.12322
Lactose tolerance:
The prebiotic GOS improved lactose tolerance (2017): http://www.pnas.org/content/114/3/E367.full
Lactobacillus rhamnosus GG helps increase tolerance to cow's milk in some children (2015): http://www.medicalnewstoday.com/articles/299817.php - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817673/
Lacto-Freedom's Proprietary L. acidophilus strain claims to end lactose intolerance: https://www.lactofreedom.com/about-lacto-freedom - https://www.amazon.com/Manzo-Pharmaceuticals-LLC-Lacto-Freedom-Probiotic/dp/B01HU4YOHS
Mental health:
Review, 2019: Effect of probiotics on depressive symptoms: A meta-analysis of human studies https://www.sciencedirect.com/science/article/abs/pii/S0165178119312156 "Probiotics are effective in reducing depressive symptoms in human studies. It is essential to verify the efficacy of specific combinations or strains of probiotics for depressive symptoms by conducting studies with a larger sample size in the future"
Review, 2018: Fermented foods, the gut and mental health: a mechanistic overview with implications for depression and anxiety https://doi.org/10.1080/1028415X.2018.1544332 "in humans, the literature relating to the relevance of fermented food for treating or preventing depression and anxiety is sparse, heterogeneous and has significant limitations"
Review, 2016: Probiotic supplementation can positively affect anxiety and depressive symptoms: a systematic review of randomized controlled trials: http://www.sciencedirect.com/science/article/pii/S0271531716301154
Multi-Probiotics ameliorate Major depressive disorder and accompanying gastrointestinal syndromes via serotonergic system regulation (May 2022, n=28) https://www.sciencedirect.com/science/article/pii/S2090123222001151 (Bifidobacterium breve CCFM1025, Bifidobacterium longum CCFM687, and Pediococcus acidilactici CCFM6432)
Bifidobacterium breve CCFM1025 attenuates major depression disorder via regulating gut microbiome and tryptophan metabolism: A randomized clinical trial (Dec 2021, n=45) https://www.sciencedirect.com/science/article/abs/pii/S0889159121006267
Effects of Lactobacillus plantarum PS128 on Children with Autism Spectrum Disorder in Taiwan: A Randomized, Double-Blind, Placebo-Controlled Trial (April 2019): https://www.mdpi.com/2072-6643/11/4/820 "ameliorated opposition/defiance behaviors, and that the total score of SNAP-IV for younger children (aged 712) improved significantly compared with the placebo group. Additionally, several elements were also notably improved"
Decreased social anxiety among young adults who eat fermented foods (2015): https://www.sciencedaily.com/releases/2015/06/150609092803.htm
Consumption of Fermented Milk Product With Probiotic Modulates Brain Activity (2013): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839572/
Lactobacillus casei strain Shirota decreases anxiety symptoms but not depression symptoms in people with CFS: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664325/ A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome (2009).
The anxiolytic effect of Bifidobacterium longum NCC3001 involves vagal pathways for gut-brain communication: http://www.ncbi.nlm.nih.gov/pubmed/21988661
Noninvasive parasite Trichuris muris caused mild to moderate colonic inflammation and anxiety-like behavior. Bifidobacterium longum normalized behavior and BDNF mRNA but did not affect cytokine or kynurenine levels: http://www.ncbi.nlm.nih.gov/pubmed/20600016
Amelioration of gastrointestinal inflammation by treatment with probiotics including L. johnsonii can alleviate anxiety (mice, 2018): https://www.nature.com/articles/s41598-018-31764-0 Immobilization stress-induced Escherichia coli causes anxiety by inducing NF-?B activation through gut microbiota disturbance
Systematic Review and Meta-Analysis: "supplementation with probiotics resulted in a statistically significant improvement in psychological symptoms compared with placebo" http://online.liebertpub.com/doi/abs/10.1089/acm.2016.0023
Bifidobacteria exert strain-specific effects on stress-related behavior and physiology in BALB/c mice: http://www.ncbi.nlm.nih.gov/pubmed/25251188
Effects of the probiotic Bifidobacterium infantis in the maternal separation model of depression: http://www.ncbi.nlm.nih.gov/pubmed/20696216
Probiotic Bifidobacterium longum NCC3001 (BB536) Reduces Depression Scores and Alters Brain Activity: http://www.sciencedirect.com/science/article/pii/S0016508517355579 - https://www.ncbi.nlm.nih.gov/pubmed/28483500
Bifidobacterium longum 1714 as a translational psychobiotic: modulation of stress, electrophysiology and neurocognition in healthy volunteers: http://www.nature.com/tp/journal/v6/n11/full/tp2016191a.html
Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve: http://www.pnas.org/content/108/38/16050.long
Oral treatment with Lactobacillus rhamnosus (JB-1) attenuates behavioural deficits and immune changes in chronic social stress: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-016-0771-7
Lactobacillus reuteri MM4-1A (ATCC-PTA-6475) Reverses Maternal Diet-Induced Social and Synaptic Deficits in Offspring: http://www.cell.com/cell/fulltext/S0092-8674(16)30730-9
Daily intake of Lactobacillus gasseri CP2305 improves mental, physical, and sleep quality among Japanese medical students enrolled in a cadaver dissection course: http://www.sciencedirect.com/science/article/pii/S1756464617300543
People focus less on bad feelings and experiences from the past (i.e. rumination) after four weeks of probiotics administration: https://www.sciencedaily.com/releases/2015/04/150414083718.htm
Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteers: http://www.ncbi.nlm.nih.gov/pubmed/25449699
Prebiotic administration normalizes lipopolysaccharide (LPS)-induced anxiety and cortical 5-HT2A receptor and IL1-ß levels in male mice: http://www.ncbi.nlm.nih.gov/pubmed/26476141
Prebiotic feeding elevates central brain derived neurotrophic factor, N-methyl-d-aspartate receptor subunits and d-serine: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3858812/
A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood: http://www.ncbi.nlm.nih.gov/pubmed/25862297
Effect of Probiotic Supplementation on Cognitive Function and Metabolic Status in Alzheimer's Disease: A Randomized, Double-Blind and Controlled Trial http://journal.frontiersin.org/article/10.3389/fnagi.2016.00256/full
Adjunctive probiotic microorganisms (L. GG and Bb12) to prevent rehospitalization in patients with acute mania: A randomized controlled trial. (2018): https://doi.org/10.1111/bdi.12652 "During the 24-week observation period there were a total of 24 rehospitalizations in the 33 individuals who received placebo and eight rehospitalizations in the 33 individuals who received the probiotics"
Early-life stress, microbiota, and brain development: Probiotics (Lactobacillus rhamnosus R0011 and Lactobacillus helveticus R0052) reverse the effects of maternal separation on neural circuits underpinning fear expression and extinction in infant rats (2019): https://www.sciencedirect.com/science/article/pii/S1878929318303037
Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 combo:
Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects (2010): https://doi.org/10.1017/S0007114510004319
Beneficial psychological effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in healthy human volunteers (2011): http://www.tandfonline.com/doi/abs/10.4161/gmic.2.4.16108
Combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces post-myocardial infarction depression symptoms and restores intestinal permeability in a rat model (2011): https://doi.org/10.1017/S0007114511005137
Probiotic mixture of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 attenuates hippocampal apoptosis induced by lipopolysaccharide in rats (2018): https://link.springer.com/article/10.1007%2Fs10123-018-00051-3 "suggest that this probiotic could play a beneficial role in some neurodegenerative conditions"
Effect of probiotic and prebiotic vs placebo on psychological outcomes in patients with major depressive disorder: A randomized clinical trial (2018): https://www.clinicalnutritionjournal.com/article/S0261-5614(18)30161-4/fulltext - significant improvements with L. helveticus R0052 and B. longum R0175 (CNCM strain I-3470), but not GOS.
Where to buy: https://naturalfactors.com/products/calmbiotic-probiotic? (NO potato starch) -http://www.lifeextension.com/Vitamins-Supplements/item02000/FLORASSIST-Mood (contains potato starch) - https://www.xymogen.com/formulas/products/102 (contains potato starch) - https://innovixlabs.com/products/mood-probiotic/ (contains potato starch). I'd recommend trying the product without potato starch first.
Vagina:
Evidence-based mixture containing Lactobacillus strains (acidophilus GLA-14 and rhamnosus HN001) and lactoferrin to prevent recurrent bacterial vaginosis: a double blind, placebo controlled, randomised clinical trial (Dec 2018) https://www.wageningenacademic.com/doi/abs/10.3920/BM2018.0075 "symptoms were significantly improved"
Efficacy of Lactobacillus Rhamnosus GR-1 and of Lactobacillus Reuteri RC-14 in the treatment and prevention of vaginoses and bacterial vaginitis relapses (2008): https://www.ncbi.nlm.nih.gov/pubmed/18854803 "results showed that 92% of the enrolled patients benefited from the treatment". 46 patients, taken orally.
Lactobacillus rhamnosus GR-1 and L. reuteri RC-14 to prevent or cure bacterial vaginosis among women with HIV. (2010): https://www.ncbi.nlm.nih.gov/pubmed/20801446 "Supplementation of probiotic L. rhamnosus GR-1 and L. reuteri RC-14 did not enhance the cure of BV among women living with HIV, but may prevent the condition among this population." 65 women.
Ingestion of yogurt containing Lactobacillus acidophilus as prophylaxis for candidal vaginitis (1992): https://www.ncbi.nlm.nih.gov/pubmed/1736766 "Daily ingestion of 8 ounces of yogurt containing Lactobacillus acidophilus decreased both candidal colonization and infection"
Ingestion of yogurt containing Lactobacillus acidophilus compared with pasteurized yogurt as prophylaxis for recurrent candidal vaginitis and bacterial vaginosis (1996): https://www.ncbi.nlm.nih.gov/pubmed/8930233 "We concluded that daily ingestion of 150 mL of yogurt, enriched with live L acidophilus, was associated with an increased prevalence of colonization of the rectum and vagina by the bacteria, and this ingestion of yogurt may have reduced episodes of BV"
Oral administration of Lactobacillus crispatus M247 to papillomavirus-infected women: results of a preliminary, uncontrolled, open trial (Apr 2021, n=35) https://archive.ph/sgkLx "After 90 days of oral treatment with a probiotic (L. crispatus M247) we observed a reduction of approximately 70% in HPV positivity"
Intravaginal:
The Comparison of vaginal cream of mixing yogurt, honey and clotrimazole on symptoms of vaginal candidiasis. (2015): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4803919 "Inside the vagina for 7 nights. This study indicated that the therapeutic effects of vaginal cream, yogurt and honey is not only similar with clotrimazole vaginal cream but is more effective in relieving some symptoms of vaginal candidiasis"
Bacterial vaginosis in pregnancy treated with yoghurt (1993): https://www.ncbi.nlm.nih.gov/pubmed/8382424 "Intravaginal application of commercial yoghurt. 7 days. Result was favorable; may be preferable to any other treatment. (A) yoghurt (n = 32) and (B) acetic acid tampon (n = 32), controls (n = 20)"
Weight:
Probiotic With or Without Fiber Controls Body Fat Mass, Associated With Serum Zonulin, in Overweight and Obese Adults—Randomized Controlled Trial: http://www.sciencedirect.com/science/article/pii/S2352396416304972
The administration of Lactobacillus gasseri was shown to decrease fat mass (visceral and subcutaneous) and body mass index in obese and type 2 diabetic patients[71]. In a double blind randomized study, the administration of Lactobacillus spp. was shown to preserve insulin sensitivity, whereas it decreased in the placebo group[72]. Amar et al. conducted a 1-month probiotic treatment with Bifidobacterium animalis (strain B420), which resulted in decreased bacterial translocation and improved insulin sensitivity, suggesting that certain probiotic interventions can reverse the adverse metabolic phenotype induced by a high-fat diet[30]. http://www.besjournal.com/Articles/Archive/2015/No11/201512/t20151218_123660.html
Probiotic supplementation (VSL#3) increases obesity with no detectable effects on liver fat or gut microbiota in obese Hispanic adolescents: a 16-week, randomized, placebo-controlled trial (2018): https://www.ncbi.nlm.nih.gov/pubmed/29493105
Bifidobacteria attenuate the development of metabolic disorders, with inter- and intra-species differences (2018) "B. adolescentis Z25 displayed an outstanding ability to alleviate metabolic syndrome, including glucose and lipid metabolism disorders, tissue damage and gut microbiota dysbiosis" http://pubs.rsc.org/en/content/articlelanding/2018/fo/c8fo00100f/unauth#!divAbstract
Other:
Review, Mar 2019: Importance of probiotics in the prevention and treatment of colorectal cancer https://onlinelibrary.wiley.com/doi/full/10.1002/jcp.28473 "Research in clinical trials encouraging findings that support a role of probiotics in CRC prevention and improve the safety and effectiveness of cancer therapy even though additional clinical research is still necessary"
Review, May 2019: Changing our microbiome: Probiotics in dermatology https://onlinelibrary.wiley.com/doi/abs/10.1111/bjd.18088
Candida: https://humanmicrobiome.info/candida
Probiotics affecting cancer & inflammation in mice: http://medicalxpress.com/news/2016-02-probiotics-modulate-liver-cancer-growth.html - http://www.pnas.org/content/113/9/E1306.abstract
Lactobacillus salivarius Isolated from Patients with Rheumatoid Arthritis Suppresses Collagen-Induced Arthritis and Increases Treg Frequency in Mice http://online.liebertpub.com/doi/10.1089/jir.2016.0057
Probiotics restore bowel flora and improve liver enzymes in human alcohol-induced liver injury: a pilot study http://www.alcoholjournal.org/article/S0741-8329(08)00301-7/abstract
Acne vulgaris, probiotics and the gut-brain-skin axis - back to the future? http://gutpathogens.biomedcentral.com/articles/10.1186/1757-4749-3-1
Lactobacillus plantarum ATCC strain 202195 + FOS synbiotic reduces sepsis risk by 40%, reduced the risk of infections by both the major groups of bacteria: the Gram-positives, by 82 percent; and the Gram-negatives, which are harder to treat with antibiotics, by 75 percent. It even reduced the risk of pneumonia and other infections of the airways by 34 percent. https://archive.fo/oJvvP
Lactobacillus reuteri 6475 (BioGaia) can protect the skeletons of older women. The women who received the powder with active bacteria had lost only half as much bone in the skeleton compared with those who received inactive powders (2018): https://www.sciencedaily.com/releases/2018/06/180621101329.htm
Probiotic Bifidobacterium lactis V9 Regulates the Secretion of Sex Hormones in Polycystic Ovary Syndrome Patients through the Gut-Brain Axis (April 2019) https://msystems.asm.org/content/4/2/e00017-19
Strain-specific:
Note: I stopped adding to this section as there would simply be way too many listings (thousands). The probiotic guide has more info on strains, and here are a few websites with strain databases:
- Probiotics Database | Discover characteristics, functionalities and scientific support of commercial probiotics, including medical informations for each strain. https://microbiome-hub.com/probiotic-strains/
- PROBIOTICS DATABASE | Exploring the World's Most Researched Probiotic Strains https://www.optibacprobiotics.com/uk/professionals/probiotics-database
Over 800 studies done on Lactobacillus GG; summary of studies:
- https://en.wikipedia.org/wiki/Lactobacillus_rhamnosus#Lactobacillus_rhamnosus_GG_.28ATCC_53103.29
- https://microbewiki.kenyon.edu/index.php/Lactobacillus_rhamnosus_GG_(ATCC_53103)_and_its_Probiotic_Use
L. plantarum 299v reduced the prevalence of iron deficiency (78% versus 59%) and iron deficiency anemia (21% versus 7.4%) towards the end of pregnancy (Apr 2021) https://medicalxpress.com/news/2021-04-probiotic-strain-pregnant-women-healthy.html
L. Reuteri ATCC 6475 Sustains Youthful Serum Testosterone Levels and Testicular Size in Aging Mice http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0084877 and much more: https://archive.is/O6Fee
L. reuteri NCIMB 30242 increases mean circulating 25-hydroxyvitamin D: http://www.ncbi.nlm.nih.gov/pubmed/23609838
Lactobacillus plantarum TWK10 Supplementation Improves Exercise Performance and Increases Muscle Mass in Mice http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848674/
Lactobacillus plantarum ATCC strain 202195 + FOS synbiotic reduces sepsis risk by 40%, reduced the risk of infections by both the major groups of bacteria: the Gram-positives, by 82 percent; and the Gram-negatives, which are harder to treat with antibiotics, by 75 percent. It even reduced the risk of pneumonia and other infections of the airways by 34 percent. https://archive.fo/oJvvP
B. thermophilum RBL67 inhibits rotavirus infection: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0164512
Bacillus coagulans GBI-30, 6086 Increases Protein and Amino Acid Absorption http://www.prweb.com/releases/2012/5/prweb9517807.htm - http://www.nutritionaloutlook.com/digestive-health/ganeden%E2%80%99s-bc30-probiotic-aids-plant-protein-digestion-study-suggests