Lactobacillus gasseri, L. gasseri, is one of the most important gastrointestinal (GI) microbes of the thousand or so species in the human intestinal microbiome. It is likely a “keystone” species, i.e., a species that is important for the proliferation and metabolism of numerous other microbes, perhaps even the composition of the entire GI microbiome. And, like Lactobacillus reuteri, it is a microbe that many of us have lost due to antibiotics and other factors.

The key features that make L. gasseri a standout among microbes includes its ability to 1) colonize the upper GI tract, and 2) produce bacteriocins, natural antibiotics effective against species such as E. coli, Klebsiella, and Staphylococcus, the species of small intestinal bacterial overgrowth, SIBO. It is my suspicion that widespread exposure to antibiotics and other factors that have reduced or eliminated important species like L. gasseri and L. reuteri that colonize the upper GI tract and produce bacteriocins are major factors responsible for the epidemic of SIBO that, by my calculations, afflict 1 in 3 Americans or >100 million people. Restoration of these two microbes can therefore be part of the solution as we do in my recipe for SIBO Yogurt (recipe in Super Gut: commercial sources, fermenting temperature, selection of prebiotic fiber).

But L. gasseri shines for other reasons, also. Among the observations made with this microbe (various strains):

  •  L. gasseri reduces perceived effects of stress
  • L. gasseri reduces visceral fat and reduces waist circumference. Two human studies with two different strains of L. gasseri have reported this effect. While some speculate that this is accomplished through increased fat oxidation (fat “burning”), I propose that it is due to the reduction in LPS endotoxemia from its upper-GI colonizing and bacteriocin-producing effects.
  • L. gasseri reduces bothersome “hot flashes,” i.e., the vasomotor symptoms of menopause. It also improves a woman’s menopausal psychological status.
  • L. gasseri reduces the symptoms of irritable bowel syndrome (IBS). Once again, I believe that L. gasseri’s unique abilities reduce the upper GI infestation of SIBO microbes responsible for many cases of IBS.
  • L. gasseri reduces symptoms of functional dyspepsia, i.e., “heartburn” after a meal.
  • Preliminary evidence suggests that L. gasseri may reduce uric acid and oxalate levels.
  • Preliminary evidence suggests that L. gasseri can reduce cognitive impairment.
  • Preliminary evidence suggests that L. gasseri suppresses Candida albicans overgrowth.

These are the effects of just one microbe.

Are you gaining an appreciation for the extraordinary power we have in reconstructing a healthy microbiome? For those of you interested in replacing this lost microbe, the evidence is best for the BNR17 strain available commercially that we then use to ferment foods such as organic half-and-half for 36 hours to generate hundreds of billions of microbial counts for larger biological effects.