Research Spotlight: L. plantarum for H. Pylori

Animal Study Finds that Lactobacillus plantarum B7 Inhibits H. pylori Growth and Attenuates Gastric Inflammation

What They Tested

The researchers asked two questions: Does Lactobacillus plantarum B7 supernatant kill H. pylori in a dish, and does feeding it to infected rats reduce stomach damage?

They measured four outcomes in rats:

• Serum TNF-α (an inflammatory cytokine)
• Gastric MDA (malondialdehyde — a marker of oxidative stress)
• Epithelial cell apoptosis (programmed cell death in the stomach lining)
• Histopathology (tissue damage and bacterial colonization under the microscope)

 In Vitro Results (the dish)

L. plantarum B7 supernatant was tested at three concentrations (1×, 5×, 10×) and two pH levels.

Key takeaways:

• Dose-dependent — more supernatant, bigger kill zone.
• pH-dependent — worked better under acidic conditions (pH 4), which matters because that's the actual stomach environment.
• The 1× concentration produced no meaningful inhibition zone — so you need a concentrated product.

In Vivo Results (the rats)

Male Sprague-Dawley rats were split into four groups:

1. Control (uninfected)
2. H. pylori infected (no treatment)
3. H. pylori + B7 at 10⁶ CFUs/mL
4. H. pylori + B7 at 10¹⁰ CFUs/mL

Gastric MDA (oxidative stress marker)

Both B7 doses knocked MDA down to near-control levels ($P = 0.000$P=0.000). That's a dramatic reduction in oxidative damage.

Other outcomes

• TNF-α dropped significantly in group 3 versus group 2 ($P < 0.05$P<0.05)
• Apoptosis of gastric epithelial cells decreased with B7 treatment
• Histology showed reduced H. pylori colonization and improved stomach inflammation in both treatment groups

Bottom Line

L. plantarum B7 does two things:

1. Directly inhibits H. pylori growth — best at low pH (stomach-like conditions) and higher concentrations
2. Dampens the inflammatory cascade — reduces TNF-α, oxidative stress (MDA), and cell death in the gastric lining

Interestingly, the lower dose (10⁶) was just as effective as the higher dose (10¹⁰) for most markers, suggesting you don't need massive CFU counts to get the anti-inflammatory benefit — though the in vitro data shows the antimicrobial effect is concentration-dependent.

Practical Angles

This is a 2012 rat study from a single Thai lab, so extrapolate cautiously — but it's part of a larger body of work showing that certain Lactobacillus strains compete with H. pylori and modulate the gastric immune response. The mechanism isn't just acid production; the fact that the supernatant still worked at neutral pH (6.5–11 mm zones at pH 7) points to secreted antimicrobial compounds (likely organic acids, hydrogen peroxide, and bacteriocins), not just the bacteria themselves acidifying the environment.

For humans dealing with chronic gastritis where H. pylori is confirmed, probiotics are worth considering as an adjunct — but they're not a replacement for proper eradication therapy when indicated. The standard triple therapy exists for a reason, and H. pylori is one of the few cases where the mainstream approach (antibiotics) is genuinely the right call for confirmed infection, because untreated H. pylori is a known driver of peptic ulcers and gastric cancer.

Source

Sunanliganon C, Thong-Ngam D, Tumwasorn S, Klaikeaw N. World J Gastroenterol 2012; 18(20): 2472–2480. From the Faculty of Medicine, Chulalongkorn University, Bangkok