Bifidobacterium longum: What It Is, Benefits, Dosage, and Sources

Nutrienting Team

April 17, 202614 min read

Bifidobacterium longum is a common and extensively studied probiotic bacterium residing in the human gut. As a member of the Bifidobacterium genus, it's one of the earliest colonizers of the infant gut and remains a significant component of the adult microbiome. Its presence is generally associated with a healthy digestive system and has been linked to various physiological benefits beyond digestion. Understanding what Bifidobacterium longum is involves recognizing its role as a beneficial microbe that contributes to the intricate balance of the gut ecosystem.

Bifidobacterium longum for Gut Health

The primary function of Bifidobacterium longum in the gut revolves around fermentation and competition. It ferments complex carbohydrates that the human body cannot digest, producing short-chain fatty acids (SCFAs) like acetate, propionate, and butyrate. These SCFAs serve as a vital energy source for colon cells, help maintain gut barrier integrity, and possess anti-inflammatory properties.

Beyond fermentation, B. longum competes with potentially harmful bacteria for nutrients and adhesion sites on the gut lining. This competitive exclusion helps prevent the overgrowth of pathogens, contributing to a stable and healthy microbial community. The presence of B. longum also influences the gut's pH, creating a slightly acidic environment that discourages the growth of many undesirable bacteria while favoring other beneficial microbes.

Practical implications of a robust B. longum population include improved digestion, particularly of certain fibers, and a more resilient gut lining. For individuals experiencing occasional digestive discomfort or those looking to support overall gut health, fostering a healthy B. longum presence can be a consideration. However, the effectiveness can vary between individuals due to unique gut microbiomes and dietary habits.

The Gut Core Microbial Species Bifidobacterium longum

Among the diverse array of microorganisms inhabiting the human gut, Bifidobacterium longum stands out as a "core" species. This designation reflects its consistent presence and significant abundance in healthy individuals across various populations. Its early establishment in infancy, often through maternal transmission, underscores its fundamental role in shaping the developing microbiome.

The term "core species" implies a foundational contribution to gut function and host well-being. B. longum contributes to the maturation of the immune system, particularly in early life, and continues to interact with immune cells throughout adulthood. It aids in the synthesis of certain B vitamins and vitamin K, showcasing its metabolic versatility beyond carbohydrate fermentation.

Trade-offs or edge cases regarding its "core" status are minimal, as its benefits are largely recognized. However, the specific strains of B. longum can exhibit different properties and efficacies. For instance, while one strain might be particularly effective at alleviating certain digestive symptoms, another might be more adept at immune modulation. This strain-specificity is a crucial nuance often overlooked when discussing probiotics broadly. A good example is the documented ability of certain B. longum strains to degrade specific prebiotics, which may not be a universal trait of all B. longum varieties.

Bifidobacterium longum - An Overview

Bifidobacterium longum is a Gram-positive, anaerobic, rod-shaped bacterium. It is one of the most common Bifidobacterium species found in the human gastrointestinal tract. Unlike many other bacteria, B. longum thrives in an environment with little to no oxygen, which is characteristic of the lower digestive tract.

Key characteristics that define B. longum and its role include:

Fermentation of complex carbohydrates: It breaks down indigestible fibers into beneficial SCFAs.
Acid production: Lactic acid and acetic acid produced by B. longum lower gut pH, inhibiting pathogen growth.
Immune modulation: It interacts with immune cells in the gut-associated lymphoid tissue (GALT), influencing immune responses.
Vitamin synthesis: Contributes to the production of certain B vitamins and vitamin K.
Adherence to gut lining: Its ability to adhere to intestinal cells is important for colonization and competitive exclusion.

The practical implications of these characteristics are broad. For instance, its acid production not only inhibits pathogens but also enhances mineral absorption, such as calcium and magnesium. Its immune-modulating properties suggest a role in managing inflammatory conditions or boosting immune defenses. However, the extent of these benefits can depend on the individual's existing gut microbiome, diet, and overall health status. A person with a severely compromised gut may experience more noticeable effects from supplementation than someone with an already robust microbiome.

Bifidobacterium Longum - Uses, Side Effects, and More

Bifidobacterium longum has been studied for a range of potential health benefits, both for general wellness and in more specific therapeutic contexts. Its uses are primarily centered around digestive health, immune support, and mental well-being, given the established gut-brain axis.

Potential Uses and Benefits (Bifidobacterium longum benefits)

Digestive Health:

Irritable Bowel Syndrome (IBS): Certain strains of B. longum* have shown promise in alleviating symptoms like abdominal pain, bloating, and irregular bowel movements in some individuals with IBS.

* Constipation: It can help improve bowel regularity by influencing gut motility and stool consistency.

* Diarrhea: May reduce the duration and severity of antibiotic-associated diarrhea and other forms of acute diarrhea.

Inflammatory Bowel Disease (IBD): While not a cure, some research suggests B. longum* could play a supportive role in managing inflammation and maintaining remission in conditions like ulcerative colitis.

Immune System Support:

B. longum* interacts with immune cells in the gut, potentially enhancing the body's immune response to pathogens and reducing the incidence of respiratory infections.

* It may help regulate inflammatory responses, which is beneficial for overall immune balance.

Mental Well-being (Gut-Brain Axis):

Emerging research indicates a link between B. longum* and improvements in mood and stress response. Some studies suggest it may help reduce symptoms of anxiety and depression by influencing neurotransmitter pathways and reducing systemic inflammation.

Allergy Management:

In some cases, B. longum* has been explored for its potential to modulate immune responses associated with allergies, particularly in infants.

Dosage and Administration (Bifidobacterium longum dosage)

The effective dosage of Bifidobacterium longum can vary significantly depending on the specific strain, the product formulation, and the intended health benefit. Probiotic dosages are typically measured in Colony Forming Units (CFUs).

General Digestive Support: Doses often range from 1 billion to 10 billion CFUs per day.
Specific Conditions (e.g., IBS, mood support): Research studies have used higher doses, sometimes up to 100 billion CFUs or more, often with specific, clinically studied strains.
Consistency is Key: For most benefits, regular, daily intake is more important than sporadic high doses.

It's crucial to follow the dosage instructions provided by the manufacturer of a Bifidobacterium longum supplement or consult with a healthcare professional for personalized guidance. The "best" dosage is highly individualized.

Side Effects (Bifidobacterium longum side effects)

For most healthy individuals, Bifidobacterium longum is well-tolerated, and side effects are generally mild and temporary.

Common Side Effects:

* Digestive Discomfort: Bloating, gas, or mild abdominal discomfort, especially when first starting a supplement. These symptoms usually subside as the body adjusts.

* Changes in Bowel Habits: Temporary changes in stool consistency or frequency.

Less Common/Serious Side Effects:

* Allergic Reactions: Rare, but possible, especially if the supplement contains other ingredients.

* Systemic Infection: Extremely rare, primarily a concern for individuals who are severely immunocompromised (e.g., critically ill, those with central venous catheters, or those with severely damaged gut barriers). In these cases, bacteria could potentially enter the bloodstream.

* Interactions: Probiotics can theoretically interact with immunosuppressants or antibiotics. If taking antibiotics, it's often advised to take probiotics a few hours apart from the antibiotic dose to maximize probiotic survival.

Who Should Exercise Caution or Avoid Bifidobacterium longum?

Severely Immunocompromised Individuals: People with compromised immune systems (e.g., undergoing chemotherapy, HIV/AIDS, organ transplant recipients) should consult a doctor before taking any probiotic.
Individuals with Central Venous Catheters: Increased risk of infection.
Those with Pancreatitis: Some studies have shown adverse outcomes with probiotics in severe acute pancreatitis.
Infants with Short Bowel Syndrome: Caution is advised.
Individuals with a History of Allergic Reactions to Probiotics: Or to other ingredients in the supplement.

Always discuss with a healthcare provider before starting any new supplement, especially if you have underlying health conditions or are taking other medications.

What is Bifidobacterium longum 35624 in Align Probiotics?

The discussion of Bifidobacterium longum often leads to specific strains, and one of the most widely recognized is Bifidobacterium longum 35624 (often abbreviated as B. longum 35624 or B. longum subsp. longum 35624). This particular strain is the active ingredient in Align Probiotics, a popular over-the-counter probiotic supplement.

The inclusion of the number "35624" after Bifidobacterium longum signifies that it is a specific, unique strain. Just as different breeds of dogs (e.g., golden retriever vs. poodle) are all Canis familiaris but have distinct characteristics, different strains of B. longum can have varying effects on the human body. This concept of "strain specificity" is paramount in probiotic science.

Characteristics and Focus of B. longum 35624:

Clinical Research: B. longum 35624 is one of the most thoroughly researched probiotic strains. It has been the subject of numerous clinical trials, primarily focusing on its efficacy in managing symptoms of Irritable Bowel Syndrome (IBS) and general digestive discomfort.
IBS Symptom Relief: Studies have indicated that B. longum 35624 can help alleviate common IBS symptoms such as abdominal pain, bloating, and gas. It is thought to achieve this by modulating gut inflammation, improving gut barrier function, and potentially influencing the gut-brain axis.
Gut Health Maintenance: Beyond IBS, it is marketed for maintaining digestive balance and supporting a healthy gut microbiome in healthy adults.
Mechanism of Action: While the exact mechanisms are still being fully elucidated, B. longum 35624 is believed to exert its effects through several pathways, including:

* Producing beneficial short-chain fatty acids.

* Competing with undesirable bacteria.

* Interacting with the gut's immune system to reduce inflammation.

* Strengthening the gut barrier.

Why Strain Specificity Matters

The case of B. longum 35624 highlights why consumers and healthcare professionals should look beyond just the genus and species name (e.g., Bifidobacterium longum) and pay attention to the specific strain designation. The benefits demonstrated for B. longum 35624 cannot be automatically attributed to all other Bifidobacterium longum strains. Each strain has its own unique genetic makeup and functional properties.

For example, if a clinical study shows that B. longum 35624 helps with IBS, it doesn't mean that any supplement containing "Bifidobacterium longum" will have the same effect. The specific strain, often indicated by a string of numbers and/or letters after the species name, is key to understanding its researched benefits.

Practical Implications for Consumers:

Read Labels Carefully: When choosing a probiotic, look for products that clearly list the full strain designation (e.g., Bifidobacterium longum 35624, Lactobacillus rhamnosus GG).
Research Specific Strains: If you are seeking a probiotic for a particular health concern, research which strains have been clinically studied for that specific purpose.
Don't Assume Universal Benefits: Understand that the benefits of one strain do not necessarily apply to others, even within the same species.

Understanding the role of specific strains like B. longum 35624 moves beyond the general understanding of Bifidobacterium longum to a more nuanced, evidence-based approach to probiotic supplementation.

Sources of Bifidobacterium longum

Bifidobacterium longum can be introduced into the body through several avenues: natural colonization, fermented foods, and dietary supplements.

Natural Colonization

As mentioned, B. longum is one of the earliest colonizers of the human gut, typically established during infancy. Breastfeeding is a significant factor in promoting the growth of Bifidobacterium species, including B. longum, in the infant gut, due to the presence of human milk oligosaccharides (HMOs) which act as prebiotics.

Fermented Foods

While some fermented foods contain various beneficial bacteria, identifying specific Bifidobacterium longum strains in these products can be challenging without laboratory testing. However, some fermented foods are known to contain Bifidobacterium species generally.

Food Source	Likelihood of Containing Bifidobacterium spp. (including B. longum)	Notes
Yogurt	High (especially if labeled "probiotic" or "live and active cultures")	Many yogurts are fortified with specific probiotic strains, including Bifidobacterium species. Check labels for specific strains.
Kefir	High	A fermented milk drink with a diverse microbial community, often including Bifidobacterium species.
Kimchi	Moderate to High	Fermented cabbage dish. Primarily contains Lactobacillus species, but Bifidobacterium can also be present, especially in later stages of fermentation.
Sauerkraut	Moderate	Fermented cabbage. Similar to kimchi, Lactobacillus species are dominant, but Bifidobacterium may be present depending on the starter cultures and fermentation conditions.
Tempeh	Low to Moderate	Fermented soybean product. Primarily uses Rhizopus fungi for fermentation, though some bacterial activity occurs. Not a primary source of Bifidobacterium unless specifically inoculated.
Miso	Low to Moderate	Fermented soybean paste. Contains Aspergillus oryzae (koji mold) and various bacteria, but Bifidobacterium is not a primary component.
Some Cheeses	Low to Moderate	Certain aged or probiotic-fortified cheeses may contain Bifidobacterium species.
Sourdough Bread	Low	Fermented with Lactobacillus and wild yeast. Not a significant source of Bifidobacterium.
Kombucha	Low	Fermented tea. Dominated by acetic acid bacteria and specific yeasts. Not a primary source of Bifidobacterium.

The presence and viability of B. longum in fermented foods can depend on:

Starter Cultures: Whether B. longum was specifically added during fermentation.
Processing: Heat treatment (pasteurization) will kill beneficial bacteria.
Storage Conditions: Temperature and time can affect bacterial survival.
Food Matrix: The specific food environment can influence bacterial growth and survival.

Dietary Supplements (Bifidobacterium longum supplement)

Probiotic supplements are the most reliable way to obtain specific, high-dose strains of Bifidobacterium longum. These supplements typically come in capsule, powder, or liquid forms.

When choosing a Bifidobacterium longum supplement:

Strain Specificity: Look for supplements that clearly list the full strain designation (e.g., Bifidobacterium longum 35624, Bifidobacterium longum BB536). This ensures you are getting a strain with documented benefits.
CFU Count: Check the Colony Forming Units (CFUs) guaranteed at the time of consumption, not just at manufacture. Higher CFUs often correlate with greater efficacy, though this is strain-dependent.
Storage Requirements: Some B. longum strains are sensitive to heat and moisture and may require refrigeration. Others are formulated to be shelf-stable. Follow storage instructions carefully.
Third-Party Testing: Look for supplements that have undergone third-party testing for purity, potency, and label accuracy.
Allergens and Inactives: Be aware of any additional ingredients, fillers, or potential allergens (e.g., dairy, soy, gluten) if you have sensitivities.

While supplements offer a targeted approach, a balanced diet rich in fermentable fibers (prebiotics) can help nourish and support the Bifidobacterium longum already present in your gut, regardless of supplement use.

FAQ

What is Bifidobacterium longum used for?

Bifidobacterium longum is primarily used to support digestive health, including managing symptoms of Irritable Bowel Syndrome (IBS), reducing constipation, and alleviating antibiotic-associated diarrhea. It's also studied for its role in immune system modulation, potentially enhancing immune responses and reducing inflammation. Emerging research suggests it may also contribute to mental well-being by influencing the gut-brain axis and reducing stress and anxiety symptoms.

Who should not take Bifidobacterium longum?

Most healthy individuals tolerate Bifidobacterium longum well. However, individuals who are severely immunocompromised (e.g., those undergoing chemotherapy, HIV/AIDS patients, organ transplant recipients), those with central venous catheters, or those with severe acute pancreatitis should consult a healthcare professional before taking Bifidobacterium longum or any probiotic. People with a history of allergic reactions to probiotics or other supplement ingredients should also exercise caution.

What foods are high in Bifidobacterium longum?

While Bifidobacterium longum naturally colonizes the human gut, it is not typically found in high concentrations in many common foods. Fermented foods like yogurt and kefir often contain various Bifidobacterium species, and sometimes specific B. longum strains if they are added as starter cultures or probiotics. However, identifying specific B. longum strains in these foods can be difficult. Probiotic supplements are the most reliable source for obtaining specific, clinically studied strains of Bifidobacterium longum in targeted dosages.

Conclusion

Bifidobacterium longum is a crucial and well-researched probiotic bacterium that plays a significant role in maintaining a healthy gut microbiome. Its contributions to digestion, immune function, and even mental well-being underscore its importance as a "core" species in the human gut. While natural colonization and some fermented foods can provide Bifidobacterium species, specific B. longum strains, such as B. longum 35624, are most reliably obtained through targeted probiotic supplements. When considering B. longum for health support, paying close attention to strain specificity and consulting with a healthcare professional can help individuals make informed decisions about its potential benefits and appropriate use.