L. gasseri is a probiotic that recently gained in popularity due to reports of weight loss and decreased blood sugar. Which of its potential benefits are backed up by science? Read on to find out.
Lactobacillus gasseri is a lactic acid bacteria that is being investigated for various potential health benefits because of its antimicrobial activity, bacteriocin production, and purported modulation of the innate and adaptive immune systems .
L. gasseri probiotic supplements have not been approved by the FDA for medical use. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
L. gasseri significantly decreased BMI, abdominal visceral fat, waist and hip circumferences, and body fat mass in 210 healthy Japanese adults, with an 8.5% decline in abdominal fat area over twelve weeks. However, the authors warned that constant consumption of this probiotic may be required to maintain this effect .
L. gasseri significantly decreased body weight and visceral and subcutaneous fat areas in adults with obese tendencies .
L. gasseri prevented weight gain in obese mice .
L. gasseri inhibited dietary fat absorption in rats .
Heat-killed L. gasseri stimulated respiratory immune responses of obese host animals to enhance their natural defense against respiratory infection .
Researchers are currently investigating whether L. gasseri has other health benefits. The potential benefits in this section have produced positive results in at least one clinical trial, but these studies are small, contradictory, or otherwise limited. Talk to your doctor before supplementing with L. gasseri for any reason.
L. gasseri exhibited anti-herpes virus (HSV-2) activity .
Heat-killed L. gasseri accelerated the resolution of symptoms and reduced mortality of enteropathogenic E. coli -infected mice .
L. gasseri increased IgA levels in breast milk and reduces the incidence of diarrhea in mouse pups with rotavirus infection .
L. gasseri suppressed H. pylori and reduced gastric mucosal inflammation in infected patients .
A 4-week treatment with L. gasseri -containing yogurt improved the efficacy of triple therapy in patients with H. pylori infection .
L. gasseri yogurt suppressed dyspeptic symptoms in H. pylori-infected patients .
Heat-killed L. gasseri improved nasal symptoms and pollen-specific IgE levels in subjects with Japanese cedar pollinosis .
L. gasseri and αLA alleviated minor resting fatigue in university-student athletes after strenuous exercise .
L. gasseri inhibited the growth of endometrial tissue in the abdominal cavity in mice and rats .
No clinical evidence supports the use of L. gasseri probiotics for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
L. gasseri increased energy expenditure, reduced blood glucose, improved glucose tolerance, and attenuated inflammation in rats .
L, gasseri decreased blood glucose and improves glucose sensitivity in type 2 diabetic mice .
L. gasseri prevented high-fat-diet-induced inflammation and lowered the ratio of inflammatory-type macrophages to anti-inflammatory ones in fat tissue of mice .
L. gasseri yogurt prevented proliferative and inflammatory changes in the stomach caused by C. albicans in mucosal candidiasis in rats .
L. gasseri degrades oxalate in laboratory experiments and may be beneficial in managing oxalate kidney stone disease .
Researchers have conducted a number of cell and animal studies to investigate the effect of L. gasseri on a biochemical level. Here are some of their findings:
- Increased IgA in infections , increased the IgG2a/IgG1 ratio , and decreased IgE in allergies .
- Increased TLR2  and BAFF .
- Increased TGF-β , and TNF-α [49, 22, 25, 44] [a study where TNF-α is decreased: 46].
- Increased IL-1β  and IL-2 [22, 20] in infections, but decreased the rate of proliferation and IL-2 production by CD4+ T in allergy .
- Mostly increased IL-6 [48, 25, 44] [a study where it is decreased: 46].
- Decreased IL-8  and IL-17A .
- Increased IL-10 [48, 49, 37, 25], IL-12 [49, 22, 25, 38], IL-15 and IL-21 .
- Increased IFN-γ , and IFNAR .
- Increased perforin 1 .
- Increased intracellular glutathione , and GLUT4 .
- Decreased CCL2, CCR2, Lep, Nos2 , sICAM-1 , ACC1, FAS, and SREBP1 [5, 15].
- Increased high-molecular-weight adiponectin .
- Increased ACO, CPT1, PPARα, PPARδ .
- Increased Mx1 and Oas1a genes, critical for viral clearance .
- Decreased CSF2 .
- Decreased serum amyloid P component .
- Increased PGE2 .
- Increased Th1 cells in allergies .
- Increased CD8(+) T cells, maintained CD8(+)CD28(+) T cells and lymphocyte transformation .
- Inhibited the proliferation of CD4+ T cells and associated inflammatory responses .
Probiotics are generally considered safe. However, the use of probiotics should be avoided in patients with organ failure, immunocompromised status, and dysfunctional gut barrier mechanisms. To prevent adverse side effects, talk to your doctor before starting a new probiotic supplement.