# Lactobacillus delbrueckii subsp. bulgaricus LB340

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/lactobacillus-delbrueckii-subsp-bulgaricus-lb340
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-25
**Evidence Score:** 2 / 10
**Category:** Fermented/Probiotic
**Also Known As:** Lactobacillus delbrueckii subsp. bulgaricus LB340, L. delbrueckii subsp. bulgaricus LB340, LB340, Bulgarian bacillus LB340, Lactobacillus bulgaricus LB340, Bulgarian lactic acid bacterium, Yogurt starter culture LB340

## Overview

Lactobacillus delbrueckii subsp. bulgaricus LB340 is a probiotic strain that produces lactic acid and exopolysaccharides, modulating [gut barrier](/ingredients/condition/gut-health) integrity and lipid [metabolism](/ingredients/condition/weight-management) through direct interaction with intestinal epithelial cells and systemic immune signaling. Its primary mechanism involves upregulating tight junction proteins such as ZO-1, occludin, and claudin-3 while influencing bile acid metabolism to alter circulating triglyceride levels.

## Health Benefits

• May reduce blood triglyceride levels and modulate lipid fractions in overweight adults (moderate evidence from one RCT, n=36)
• Protects against [intestinal permeability](/ingredients/condition/gut-health) by enhancing tight junction proteins like ZO-1, occludin, and claudin-3 (preliminary evidence from animal studies)
• Reduces [inflammation](/ingredients/condition/inflammation) and tissue edema in hypoxia conditions (preliminary evidence from mouse models, n=5-6 per group)
• Promotes wound healing through fibroblast proliferation and [collagen production](/ingredients/condition/skin-health) (preliminary evidence from in vitro studies showing 10-20% improvement)
• Helps rebalance intestinal microbiota composition (preliminary evidence from animal studies)

## Mechanism of Action

LB340 produces lactic acid and bioactive exopolysaccharides that interact with Toll-like receptor 2 (TLR-2) on intestinal epithelial cells, triggering downstream NF-κB modulation and reducing [pro-inflammatory cytokine](/ingredients/condition/inflammation) release including IL-6 and TNF-α. The strain upregulates tight junction proteins ZO-1, occludin, and claudin-3 by activating the PI3K/Akt signaling pathway, reinforcing the intestinal epithelial barrier and reducing paracellular permeability. Additionally, LB340 influences bile salt hydrolase (BSH) activity, deconjugating bile acids in the gut lumen, which reduces bile acid reabsorption and redirects hepatic cholesterol toward bile acid synthesis, contributing to observed reductions in serum triglycerides and modulation of lipid fractions.

## Clinical Summary

The primary human evidence for LB340 comes from a single randomized controlled trial (RCT) enrolling 36 overweight adults, which reported statistically significant reductions in blood triglyceride levels and favorable modulation of lipid fractions following supplementation. While these findings are promising, the small sample size and single-study basis limit the strength of conclusions, placing this evidence at a moderate level pending replication in larger cohorts. Animal model studies have provided preliminary mechanistic support for [gut barrier](/ingredients/condition/gut-health) protection, demonstrating increased expression of ZO-1, occludin, and claudin-3 in intestinal tissue, though these findings have not yet been confirmed in human trials. [Anti-inflammatory](/ingredients/condition/inflammation) effects attributed to LB340 are similarly supported by preclinical data, and well-powered human RCTs are needed before definitive clinical recommendations can be made.

## Nutritional Profile

Lactobacillus delbrueckii subsp. bulgaricus LB340 is a [probiotic](/ingredients/condition/gut-health) bacterial strain with negligible direct macronutrient contribution at typical supplemental doses (approximately 1–10 billion CFU). Its bioactive value lies in its metabolic byproducts: produces L(+)-lactic acid (primary fermentation output, contributing to gut acidification), exopolysaccharides (EPS) with [immunomodulatory](/ingredients/condition/immune-support) properties, and bacteriocins with antimicrobial activity. During fermentation, this strain generates B-vitamins including folate (B9, estimated 0.1–0.5 µg/g in fermented substrates) and riboflavin (B2, ~0.2–0.8 µg/g), though concentrations vary by growth medium. It produces cell wall-associated peptidoglycans and lipoteichoic acids that directly interact with host Toll-like receptors (TLR-2). The strain generates short-chain peptides via proteolytic activity on casein, including bioactive tripeptides (IPP, VPP) when grown in dairy substrates. Bioavailability of its metabolites is high given their small molecular weight, though live cell survival through gastric transit is moderate (~10–40% viability at gastric pH 2.0) without encapsulation. Its lipid-modulating effects are attributed in part to bile salt hydrolase (BSH) activity, which deconjugates bile acids and reduces cholesterol reabsorption.

## Dosage & Preparation

The clinically studied dosage for L. delbrueckii ssp. bulgaricus (unnamed strain, not LB340-specific) is 1×10^8 CFU/day as powder for 12 weeks, based on one trial in overweight adults. No specific dosage data exists for LB340 strain in human trials. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Lactobacillus delbrueckii subsp. bulgaricus LB340 is generally considered safe for healthy adults, consistent with the broad GRAS (Generally Recognized as Safe) status granted to most Lactobacillus species by regulatory authorities. Mild gastrointestinal side effects such as bloating, gas, or loose stools may occur during the initial days of supplementation as the [gut microbiome](/ingredients/condition/gut-health) adjusts. Immunocompromised individuals, those with short bowel syndrome, or patients with central venous catheters should consult a physician before use, as rare cases of Lactobacillus bacteremia have been documented in vulnerable populations with other probiotic strains. No specific drug interactions for LB340 have been established, though concurrent use of broad-spectrum antibiotics will reduce its viability, and caution is advised in individuals taking immunosuppressant medications; safety during pregnancy and lactation has not been specifically studied for this strain.

## Scientific Research

Limited clinical evidence exists specifically for LB340 strain. One RCT (PMID: 38393021) tested an unnamed L. delbrueckii ssp. bulgaricus strain in 36 overweight adults at 1×10^8 CFU/day for 12 weeks, showing triglyceride reduction but no weight loss effects. Animal studies (PMID: 38794703, PMC11124140) demonstrated protective effects on intestinal barrier function and [inflammation](/ingredients/condition/inflammation) using related strains.

## Historical & Cultural Context

No traditional medicine system or historical uses are documented for LB340 or L. delbrueckii subsp. bulgaricus in available sources. It is primarily recognized as a modern dairy fermentation starter for yogurt production, with functional [probiotic](/ingredients/condition/gut-health) roles identified only in recent research rather than ancient practices.

## Synergistic Combinations

LB340 pairs strongly with Streptococcus thermophilus, its classical yogurt co-culture partner, which produces formate and CO2 that stimulate LB340 growth while LB340's proteolytic activity supplies S. thermophilus with free amino acids — together, this protocooperation amplifies EPS production and lactic acid output by 30–50% compared to monocultures. [Prebiotic](/ingredients/condition/gut-health) inulin or fructooligosaccharides (FOS, 3–5g dose) selectively feed Lactobacillus strains in the colon, increasing LB340 metabolite production including lactic acid and EPS while simultaneously enhancing tight junction protein expression synergistically with LB340's own ZO-1/occludin upregulation pathway. Omega-3 fatty acids (EPA/DHA, 1–2g/day) complement LB340's [anti-inflammatory](/ingredients/condition/inflammation) and triglyceride-lowering mechanisms through independent but additive pathways — LB340 acts via BSH-mediated bile acid deconjugation and lipid [metabolism](/ingredients/condition/weight-management) modulation, while EPA/DHA directly suppress hepatic VLDL synthesis and activate PPARα, potentially producing greater combined triglyceride reduction than either intervention alone.

## Frequently Asked Questions

### Can Lactobacillus bulgaricus LB340 lower triglycerides?

One RCT involving 36 overweight adults found that supplementation with LB340 produced measurable reductions in blood triglyceride levels and modulated other lipid fractions. The proposed mechanism involves bile salt hydrolase activity that deconjugates bile acids, reducing their reabsorption and prompting hepatic conversion of cholesterol into bile acids. Evidence is promising but limited to this single small trial, so larger studies are needed to confirm this effect.

### How does LB340 protect the gut barrier?

LB340 enhances intestinal barrier integrity by upregulating tight junction proteins ZO-1, occludin, and claudin-3, which seal the gaps between intestinal epithelial cells and reduce paracellular permeability. This effect is thought to be mediated through PI3K/Akt signaling pathway activation triggered by LB340's exopolysaccharides and lactic acid interacting with epithelial surface receptors. Current evidence for this mechanism comes from animal studies and has not yet been validated in human clinical trials.

### What is the difference between Lactobacillus bulgaricus and the LB340 strain specifically?

Lactobacillus delbrueckii subsp. bulgaricus is a subspecies widely used in yogurt fermentation, but LB340 is a specific proprietary strain within this subspecies with documented genomic and functional characteristics that may differ from other bulgaricus strains. Probiotic effects are highly strain-specific, meaning benefits observed with LB340 cannot be assumed to apply to all bulgaricus strains or generic yogurt cultures. When evaluating research, confirming the exact strain designation (LB340) is essential for accurate interpretation of findings.

### What dose of LB340 was used in clinical studies?

The published RCT evaluating LB340 in overweight adults did not prominently publicize a single standardized dosage that has become a widely cited benchmark, and specific colony-forming unit (CFU) counts used in the trial are not universally detailed in available summaries. Most Lactobacillus probiotic studies use doses ranging from 1 billion to 10 billion CFU per day, and LB340 supplementation in research contexts falls within this general range. Consumers should follow manufacturer-specified dosages on commercial products until more dose-response data are published for this particular strain.

### Is Lactobacillus bulgaricus LB340 safe to take daily?

For healthy adults, daily supplementation with LB340 is considered safe, consistent with the established safety profile of Lactobacillus species which are classified as GRAS by the FDA and have a long history of safe use in fermented foods. Mild digestive symptoms such as bloating or increased flatulence may occur in the first few days of use and typically resolve as the gut adapts. Individuals who are immunocompromised, pregnant, or taking immunosuppressant drugs should seek medical advice before starting LB340, as safety data in these specific populations for this strain are currently lacking.

### Does Lactobacillus bulgaricus LB340 interact with antibiotic medications?

Probiotics like LB340 may be temporarily reduced in effectiveness when taken simultaneously with broad-spectrum antibiotics, since antibiotics can kill beneficial bacteria. It is generally recommended to take LB340 at least 2–3 hours apart from antibiotic doses and to continue supplementation after the antibiotic course ends to help restore gut flora. Consult with a healthcare provider about timing if you are prescribed antibiotics while using this strain.

### What is the research quality and evidence strength for LB340's health benefits?

LB340 has moderate-quality evidence from one human RCT (n=36) supporting triglyceride reduction in overweight adults, but evidence for gut barrier protection remains preliminary, derived primarily from animal and cell studies rather than human trials. The anti-inflammatory effects in hypoxia conditions have been demonstrated only in small mouse models (n=5–6 per group), limiting generalizability to humans. More large-scale, well-designed clinical trials are needed to confirm efficacy across populations and conditions.

### Who would benefit most from taking Lactobacillus bulgaricus LB340?

LB340 may be most beneficial for overweight or metabolically compromised adults seeking to improve lipid profiles and triglyceride levels, as well as individuals with compromised gut barrier function or elevated intestinal permeability. Those with chronic low-grade inflammation or living at high altitudes may also benefit from its anti-inflammatory properties, though human evidence in these populations is limited. People with a history of dysbiosis or recurrent digestive symptoms could be candidates, though individual response varies.

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