B. longum is an amazing probiotic that boosts immunity. This bacterium can improve allergies, Celiac disease, and IBS and has many other health benefits.

What is Bifidobacterium longum?

Bifidobacterium longum is a Gram-positive, rod-shaped bacterium present in the human GI tract. It’s subspecies B. longum subsp. infantis is one of the earliest bacteria to colonize the infant gut. B. longum is often added to food products as a probiotic with various health benefits.

Previously considered separate species, B. infantis and B. suis were shown to be subspecies of B. longum [1].

Health Benefits of B. longum

1) Boosts Immunity

B. longum ssp. infantis triggers the anti-poliovirus response in infants [2].

B. longum ssp. infantis promotes immune responses in human volunteers [3].

B. longum ssp. infantis has strong immunomodulatory effect in the elderly, compared with other well-known commercial strains [4].

B. longum stimulates the immune functions in the elderly [5].

B. longum Combats Infections

B. longum reduces the incidence of influenza and fever in subjects with influenza vaccination [6].

B. longum fed infants showed a trend toward fewer respiratory tract infections [7].

B. longum protects mice against pneumonia-induced death by finely tuning the inflammatory response and speeding up lung recovery [8].

B. longum improves symptoms, reduces mortality and suppresses inflammation in the lower respiratory tract in mice infected with influenza [9, 10].

B. longum ssp. infantis inhibits rotavirus infection in mice [11].

Oral administration of B. longum protects mice against gut-derived sepsis caused by P. aeruginosa [12].

B. longum improves survival in mice infected with Salmonella Typhimurium [13].

B. longum ssp. infantis protects against Salmonella associated injury in mice via a Treg-dependent mechanism [14, 15].

B. longum May be Beneficial Against Candida

B. longum inhibits the growth of C. albicans and other pathogenic bacteria [16].

2) Relieves Inflammation

B. longum ssp. infantis reduced proinflammatory markers in patients with ulcerative colitis, chronic fatigue syndrome, and psoriasis [17].

B. longum reduces inflammation and improves symptoms in patients with ulcerative colitis [18].

B. longum significantly alleviates inflammation in mice with gout [19].

B. longum ssp. infantis suppresses proinflammatory IL-17 cytokine production and may be useful in the treatment of Th17-mediated diseases [20].

3) Ameliorates Allergies

Intake of yogurt or powder supplemented with B. longum alleviated subjective symptoms and affected blood markers of allergy in individuals with Japanese cedar pollinosis [21, 22, 23]. Nasal symptoms such as itching, rhinorrhea, and blockage as well as throat symptoms tended to be relieved with this probiotic [24].

B. longum attenuates allergic airway inflammation [25], and food allergy symptoms in mice [26].

Oral administration of B. longum suppresses IgE levels and improves the IgG2a/IgG1 ratio. It also increases Th1 cytokine and decreases Th2 cytokine production in mice [27].

B. longum balances the Th1/Th2 response and alleviates β-lactoglobulin allergic inflammation in mice [28].

Neonatal mother-to-offspring colonization with B. longum reduces allergic responses in mice [29].

4) Beneficial in Celiac Disease

B. longum ssp. infantis reduces gastrointestinal symptoms in untreated Celiac disease (CD) patients [30].

B. longum improved gut microbiota composition and immune parameters in children with newly diagnosed CD [31].

Oral administration of B. longum ameliorates gliadin (gluten)-mediated perturbations in liver iron deposition and mobilization in rats with CD [32].

B. longum attenuates the production of inflammatory cytokines and the CD4+ T-cell mediated immune response and protects newborn rats against gliadin (gluten)-induced enteropathy [33].

5) Lowers Cholesterol

B. longum reduced total cholesterol, particularly among subjects with moderate hypercholesterolemia [34].

B. longum supplementation significantly reduced total cholesterol, liver lipid deposition, and adipocyte size and positively affected liver and kidney function in hypercholesterolemic rats [35].

Rats fed a cholesterol-enriched diet supplemented with B. longum had significantly lower triglycerides, LDL-C, very-low-density lipoprotein (VLDL) cholesterol, and MDA [36, 37].

6) May be Beneficial in Metabolic Syndrome

B. longum improves metabolic parameters in rats on a high-fat diet. This probiotic also reduced metabolic endotoxin concentrations and intestinal inflammation [38].

7) Beneficial for the GI Tract

B. longum Improves Gut Microbiota

Enterotoxigenic Bacteroides fragilis (ETBF) strains have been suggested to be associated with acute and persistent diarrhea, inflammatory bowel disease and colorectal cancer. B. longum significantly decreased ETBF in humans [39].

B. longum modulates the intestinal environment and may improve the health care of elderly patients receiving enteral feeding [40].

B. longum supplementation elevated biotin levels produced by Bacteroides caccae, and increased Eubacterium rectale, a butyrate producer, in mice [41].

B. longum maintains high Lactobacilli levels in mice [42].

B. longum ssp. infantis modulates the gut microbiota and reduces endotoxins in rats [43].

B. longum ssp. infantis increases propionic, succinic acid and butyric acid in rats [44].

B. longum Improves Intestinal Inflammation

Administration of B. longum ssp. infantis significantly reduces the incidence of necrotizing enterocolitis (NEC) and associated inflammation in rats [45].

B. longum improves colitis in mice [46].

B. longum ssp. infantis ameliorates colitis in rats [44] and mice by decreasing Th1 and Th17 responses [47].

B. longum Ameliorates IBS

B. longum ssp. infantis reduces intestinal inflammation and was shown to efficiently treat individual and global IBS symptoms without adverse events [48].

B. longum ssp. infantis improved abdominal pain/discomfort, bloating/distention, and bowel movement difficulty in patients with IBS [49].

B. longum ssp. infantis was shown to relieves many of the symptoms of IBS in a clinical trial involving women [50].

B. longum ameliorated ulcerative colitis symptoms in Japanese patients [51].

B. longum and B. longum subsp. infantis ameliorate ulcerative colitis in mice [42, 52].

B. longum reduces visceral hypersensitivity in mice with IBS [53].

B. longum ssp. infantis significantly reduced visceral pain, threshold pressure of the first pain behavior and total number pain behaviors in rats [54, 55].

8) May Boost Cognitive Function

B. longum fed mice exhibit improved learning and memory [56].

9) May Alleviate Anxiety

B. longum normalizes anxiety-like behavior and hippocampal brain-derived neurotrophic factor (BDNF) in mice with infectious colitis [57].

10) May Combat Depression

Depression can be reversed in rats by administering B. infantis [49].

Chronic administration of B. infantis protects rats from depressive symptoms caused by stress induced through maternal separation [58].

11) May be Beneficial in Schizophrenia

Daily administration of B. longum reduced schizophrenic rearing behavior in mice, decreased the resting level of plasma corticosterone and the ratio of kynurenine to tryptophan [59].

12) May be Beneficial for the Lungs

B. longum treatment significantly improved lung injury following infection and sepsis in mice. This probiotic also decreased lung inflammatory responses [60].

13) Great for the Skin

B. longum extract, when applied to the skin, was able to improve inflammation parameters, decrease skin sensitivity, increase skin resistance against physical and chemical aggression, and decrease skin dryness in volunteers with sensitive skin [61].

B. longum exerts photoprotective effects on the skin in mice [62].

14) Beneficial for Liver Health

B. longum and fructooligosaccharides (FOS) significantly reduced AST, CRP, HOMA-IR, blood endotoxin and steatosis in patients with non-alcoholic steatohepatitis (NASH) [63].

B. longum and FOS improved biochemical parameters and neuropsychological tests in cirrhotic patients with minimal hepatic encephalopathy (MHE) [64].

15) Beneficial in Patients Receiving Hemodialysis

Oral administration of B. longum decreases serum phosphate levels in patients receiving hemodialysis (HD) [65].

The administration of B. longum can decrease the serum concentrations of indoxyl sulfate and P-cresol in HD patients [66, 67].

In addition, Bifidobacteria produce vitamin B12 and folate, which can normalize serum homocysteine levels in HD patients [65].

16) May be Beneficial for Bone Health

B. longum supplementation alleviated bone loss and increased bone formation parameters and bone mass density in ovariectomized rats [68].

17) Combats Cancer

Dietary B. longum significantly inhibited colon and liver and small intestinal tumors in male rats. In female rats, dietary supplementation also suppressed mammary carcinogenesis [69].

B. longum inhibits colorectal tumors in mice [70] and rats [71].

Freeze-dried cultures of B. longum significantly suppressed colon tumor incidence and tumor multiplicity and also reduced tumor volume in rats [72].


In Inflammation B. longum:

  • Decreases Th1-related cytokines (T-bet, IL-2, and IFN-γ) and Th17-related cytokines (IL-12p40, RORγt, IL-17A, IL-21, and IL-23), and increases Treg-related molecules (Foxp3, IL-10, and TGF-β) [47, 73, 19, 20, 3, 45].
  • Decreases IL-1α [18], IL-1β [46, 53, 19], IL-6 [74, 17, 45] and IL-18 [53].
  • Decreases TNF-α expression [46, 18, 17, 45].
  • Increases IL-27 [20].
  • Decreases CD80 and CD40 [73], CXCL1 [19, 45], CRP [17], iNOS and antimicrobial peptides Reg3b and Reg3g [45].

In Infection B. longum:

  • Increases Natural killer (NK) cell activity [5, 6, 9].
  • Increases serum IgA [5] and decreases IgG2a productions [13].
  • Increases IL-2, IL-12, and IL-18 [9].
  • Decreases IL-6 [9, 10] and IL-8 [15].
  • Decreases TNF-α [9].
  • Both increases [8] and decreases IL-10 [15], and decreases [10, 13] and increases IFN-γ [9].

In Allergy B. longum:

  • Decreases IgE and improves the IgG2a/IgG1 ratio [27, 29, 75, 75, 76].
  • Increases IgA [77].
  • Increases Th1 cytokine and decreases Th2 cytokine production [27].
  • Decreases IL-4 [75, 25] and IL-5 [75] [a case where IL-5 was increased: 25].
  • Increases IL-10 [29], IL-12 [76, 76] and TGF-β [29].
  • Increases [24, 76] or decreases IFN-γ [25].
  • Suppresses MDC and TARC [22].
  • Increases CD4+CD25+Foxp3+ Treg cells [28].

In Coeliac Disease B. longum:

  • Decreases TNF-α [31, 33].
  • Increases NFκB [33].
  • Increases IL-10 [33].
  • Reduces CD3⁺ T [31], CD4+ and CD4+/Foxp3+ cells [33] and increased CD8+ T [33].
  • Increases MIP-1β [30].


B. longum is considered safe, but should be avoided in immunocompromised individuals, people with organ failure, and dysfunctional gut barrier, where probiotics may lead to infection.

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About the Author

Biljana Novkovic - PHD (ECOLOGICAL GENETICS) - Writer at Selfhacked

Dr. Biljana Novkovic, PhD

PhD (Ecological Genetics)

Biljana received her PhD from Hokkaido University.

Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science & health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

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