Effect of whey-based culture supernatant of Lactobacillus acidophilus (johnsonii) La1 on Helicobacter pylori infection in humans

Background: Specific strains of Lactobacillus acidophilus are known to inhi bit intestinal cell adhesion and invasion by enterovirulent bacteria. As L. acidophilus can survive transiently in the human stomach, it may downregul ate Helicobacter pylori infection. Methods: The ability of L. acidophilus ( johnsonii) La1 supernatant to interfere with H. pylori bacterial growth, ur ease activity, and adhesion to epithelial cells was tested in vitro. Its ef fect on H. pylori infection in volunteers was monitored in a randomized, do uble-blind, controlled clinical trial, using a drinkable, whey-based, La1 c ulture supernatant. H. pylori infected volunteers were treated 14 days with 50 mi of La1 supernatant four times a day combined with either omeprazole 20 mg four times a day or with placebo. Infection was assessed by breath te st, endoscopy, and biopsy sampling, performed at inclusion, immediately at the end of the treatment (breath test only), and 4 weeks after the end of t he treatment. Results: La1 supernatant inhibited H. pylori growth in vitro, regardless of previous binding of H. pylori to epithelial cells. In 20 sub jects (8 females, 12 males, mean age 33.1 years) a marked decrease in breat h test values was observed immediately after treatment with La1 supernatant , both in the omeprazole and in the placebo group (median 12.3 vs. 28.8 and 9.4 vs. 20.4, respectively; p < 0.03). In both treatment groups, breath te st values remained low 6 weeks after treatment (omeprazole treated 19.2, pl acebo treated 8.3; p < 0.03 vs. pretreatment), but the persistence of H. py lori infection was confirmed in gastric biopsies. Conclusion: La1 culture s upernatant shown to be effective in vitro has a partial, acid-independent l ong-term suppressive effect on H. pylori in hu mane.