Lactobacilli Bulgaricus
Also known as: Lactobacillus bulgaricus, L. bulgaricus, Bulgarian bacillus, Lactobacillus delbrueckii subsp. bulgaricus
Overview
Lactobacillus delbrueckii subsp. bulgaricus, commonly known as L. bulgaricus, is a Gram-positive, rod-shaped bacterium renowned for its role in the fermentation of dairy products like yogurt and kefir. It is widely utilized as a probiotic supplement to support gastrointestinal health, modulate immune function, and potentially improve certain metabolic markers. This bacterium is characterized by its ability to produce lactic acid, which lowers gut pH and inhibits the growth of pathogenic bacteria. While it survives transit through the upper gastrointestinal tract and can temporarily colonize the gut, it does not establish permanent residence, requiring consistent supplementation for sustained benefits. Research on L. bulgaricus is moderately mature, with several randomized controlled trials (RCTs) and systematic reviews supporting its efficacy, particularly for gastrointestinal and metabolic outcomes. The evidence quality is generally robust, though study designs and sample sizes can vary.
Benefits
Lactobacillus bulgaricus offers several evidence-based benefits, primarily in gastrointestinal health and metabolic regulation. For gastrointestinal health, meta-analyses indicate that L. bulgaricus, often in combination with other probiotics, can reduce the incidence of diarrhea. Studies show a relative risk reduction of 10–20% in some populations, making it clinically relevant for at-risk individuals, with benefits typically observed within 2–8 weeks. In terms of metabolic markers, a recent randomized controlled trial demonstrated that L. bulgaricus supplementation led to a significant decrease in triglyceride (TG) levels (−21.00 ± 11.61 mg/dL, p = 0.0447) and a significant decrease in AST levels (p = 0.0147) compared to placebo. While these metabolic effects are modest, they suggest a potential role in improving specific markers. Most evidence supports its use in adults; data for children or the elderly are limited. No significant effects on blood glucose, HbA1c, insulin, cholesterol, or HDL have been consistently observed.
How it works
Lactobacillus bulgaricus primarily exerts its effects by modulating the gut microbiota composition and activity. It produces lactic acid, which lowers the pH within the gut, creating an unfavorable environment for many pathogenic bacteria and inhibiting their growth. This action contributes to a healthier microbial balance. Additionally, L. bulgaricus is believed to enhance gut barrier function, strengthening the intestinal lining and reducing permeability. It also plays a role in immune modulation, interacting with the host's immune system, although the exact molecular targets are not fully elucidated. While it transiently colonizes the gut, it does not establish permanent residence, meaning continuous supplementation is necessary to maintain its beneficial effects. Its primary interaction is with the gastrointestinal tract, with secondary effects observed on metabolic and immune systems.
Side effects
Lactobacillus bulgaricus is generally recognized as safe (GRAS) for most populations. Side effects are rare and typically mild, primarily involving gastrointestinal symptoms such as bloating and gas, which may occur in sensitive individuals. These common side effects are reported in less than 5% of users. Uncommon side effects (1–5%) are very rare, with no significant adverse events reported in recent randomized controlled trials. Serious adverse events are extremely rare, with no reports in large-scale studies. There are no significant drug interactions reported with L. bulgaricus. However, caution is advised for individuals who are severely immunocompromised due to a theoretical, albeit extremely low, risk of bacteremia. For special populations, L. bulgaricus is considered safe for most adults, but data for children, pregnant, or lactating women are limited, and its use in these groups should be discussed with a healthcare professional.
Dosage
The minimum effective dose for Lactobacillus bulgaricus is not definitively established, but most studies utilize a range of 1–10 billion CFU (colony-forming units) per day. The optimal dosage range is generally considered to be 5–10 billion CFU per day, often taken in combination with other probiotic strains for synergistic effects. Doses up to 20 billion CFU per day have been used in studies without reported adverse effects, indicating a high safety margin, though a maximum safe dose has not been formally established. L. bulgaricus can be taken with or without food, as the timing of administration does not significantly impact its efficacy. For stability and improved gastric transit survival, encapsulated forms or those delivered within fermented foods are preferred. No specific cofactors are required for its absorption or activity.
FAQs
Is L. bulgaricus safe for daily use?
Yes, L. bulgaricus is generally recognized as safe for most healthy adults, with rare and mild gastrointestinal side effects. Consistent daily use is often recommended for sustained benefits.
When is the best time to take L. bulgaricus?
L. bulgaricus can be taken at any time of day, with or without food. Consistency in daily intake is more important than the specific timing for achieving its benefits.
What kind of results can I expect from L. bulgaricus?
You can expect modest improvements in gut health, such as reduced diarrhea incidence, and potentially minor improvements in certain metabolic markers like triglycerides, typically within a few weeks of consistent supplementation.
Does L. bulgaricus permanently colonize the gut?
No, L. bulgaricus does not permanently colonize the gut. Its benefits are transient, meaning continuous and regular supplementation is required to maintain its positive effects on gut microbiota and overall health.
Research Sources
- https://www.frontiersin.org/journals/gastroenterology/articles/10.3389/fgstr.2022.983075/full – This systematic review and meta-analysis by Carona et al. (2022) examined the efficacy of L. acidophilus and L. bulgaricus, often in combination, in reducing diarrhea incidence. The study found that these probiotics significantly reduced diarrhea compared to placebo, highlighting their role in gastrointestinal health despite some heterogeneity in study designs.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10890272/ – Chu et al. (2024) conducted a randomized controlled trial investigating L. bulgaricus supplementation. Their findings indicated a significant reduction in triglyceride and AST levels compared to placebo, suggesting a potential benefit for specific metabolic markers, although the study had a moderate sample size.
- https://jamanetwork.com/journals/jama/fullarticle/1151505 – This systematic review and meta-analysis by Hempel et al. (2012) focused on the role of probiotics, including Lactobacillus species, in reducing the risk of antibiotic-associated diarrhea. The study concluded that probiotics modestly but significantly reduce this risk, providing robust evidence for their preventative use.
